Citation
Polymerization studies of 4-substituted-1, 2, 4-triazoline-3, 5- diones and synthesis of model compounds related to triple strand polymers

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Title:
Polymerization studies of 4-substituted-1, 2, 4-triazoline-3, 5- diones and synthesis of model compounds related to triple strand polymers
Added title page title:
Synthesis of model compounds related to triple strand polymers
Creator:
Turner, S. Richard, 1942-
Publication Date:
Copyright Date:
1971
Language:
English
Physical Description:
ix, 157 leaves. ; 28 cm.

Subjects

Subjects / Keywords:
Absorption spectra ( jstor )
Adducts ( jstor )
Chlorides ( jstor )
Copolymerization ( jstor )
Copolymers ( jstor )
Ethers ( jstor )
Flasks ( jstor )
Hydrogen ( jstor )
Infrared spectrum ( jstor )
Polymers ( jstor )
Chemistry thesis Ph. D ( lcsh )
Dissertations, Academic -- Chemistry -- UF ( lcsh )
Polymers and polymerization ( lcsh )
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bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis - University of Florida.
Bibliography:
Bibliography: leaves 153-156.
General Note:
Manuscript copy.
General Note:
Vita.

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University of Florida
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University of Florida
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Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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Full Text














POLYMERIZATION STUDIES OF

4-SUBSTITUTED -1 24-TRIAZOLINE-3, 5-DIONES

AND

SYNTHESIS OF MODEL COMPOUNDS

RELATED TO TRIPLE STRAND POLYMERS








By

SAM RICHARD TULNm'R








A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF

THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE

REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY









UNIVERSITY OF FLORIDA

1971
















This dissertation is dedicated to my parents.















ACKNOWLEDGEMENTS

My stay at the University of Florida has been a pleasant and

rewarding experience and I would like to offer my gratitude to the

many people who have made this experience possible.

I will be forever indebted to my advisor, Dr. George B. Butler,

for his patience, understanding, encouragement and guidance during

the course of this work.

I wish to thank Dr. W. R. Dolbier, Dr. J. A. Deyrup, Dr. M. T.

Vala and Dr. R. B. Bennett for giving of their valuable time to serve

on my supervisory committee. Also I wish to thank Dr. T. Hogen Esch

for his informing discussions with me on portions of this work.

The successful completion of this work would not have been

possible without the assistance of Dr. Lawrence J. Guilbault. His

enthusiastic and tireless research efforts have been and will always

be a great example for me.

Grateful thanks are extended to my fellow laboratory colleagues.

They have generated a pleasant and stimulating environment in which

to work.

I also wish to acknowledge the Air Force Office of Scientific

Research, the Petroleum Research Fund and the Tennessee Eastman

Company for providing financial support in the form of research

assistantships.

Finally, I wish to thank my wife, Pamela, for her love and under-

standing which have made the completion of this work an easier task.















TABLE OF CONTENTS


Page

ACKNOWLEDGEMENTS . . . . . . . . . . iii

LIST OF TABLES . . . . . . . .... . . . . v

LIST OF FIGURES . . . . . ... .... . . vi

ABSTRACT . . . . . . . . . . . . vi

CHAPTER

I. INTRODUCTION . . . . . . . . . . 1

A. Polymerization Studies of Azo Dienophiles .. 1
B. Triple Strand Polymer Model Compound Studies 9

II. POLYMERIZATION STUDIES OF 4-SUBSTITUTED-1,2,4-
TRIAZOLINE-3,5-DIONES . . . . . . . . 14

A. Copolymerization of Ethyl Vinyl Ether and Divinyl
Ether with 4-Phenyl-1,2,4-triazoline-3,5-dione 14
B. Copolymerization of 4-Phenyl-1,2,4-Triazoline-
3,5-dione with Other Monomers . . . . .. 46
C. Reactions and Attempted llomopolymierizations of
4-Phcnyl-1,2,4-triazoline-3,5-dione . . .. 53
D. Diels Alder Polymers . . . . . . . 58

III. TRIPLE STRAND POLYMER MODEL COMPOUND STUDIES . . 66

A. Attempted Synthesis of Tetracyclo[4.4.0.13'9.1 ]
Dodecane and Related Systems . . . ... 66
B. Attempted Synthesis of 5,5,6,6-Tetrasubstituted
Cyclohexadiene Structures . . . . . .. 82

IV. EXPERIMENTAL . . . . . . . . .. 86

A. General . . . . . . . . . . 86
B. Copolymerizations and Related Reactions of 4-
Substituted-l,2,4-triazoline-3,5-diones . .. 87
C. Syntheses Related to Triple Strand Model Compound
Studies . . . . . . . . . . 121

REFERENCES CITED . . . . . . . . . . . 153

BIOGRAPHICAL SKETCH . . . . . . . 157














LIST OF TABLES


Table


Copolymerizations of EVE and PhTD . . . . . .

Copolymerizations of DVE and PhTD . . . . .

First Order Rate Constants in PhTD at 25C . . . .

Summary of Interception Reaction Results . . . .

Copolymerizations and Reactions of PhTD and Other
Monomers . . . . . . . . . . . ....

Summary of Catalyzed PhTD Reactions . . .

Catalytic Hydrogenation of Diazoquinone Adducts . ..

Reactions of Tetracyanoethylene with a-Pyrone . .


Page

29

31

37

43


47

57

81

83















LIST OF FIGURES


Figure Page

1 Nmr spectrum of the copolymer of ethyl vinyl ether and
4-phenyl-1,2,4-triazoline-3,5-dione. . . . .. 16

2 Nmr spectrum of 3-phenyl-6-vinyloxy-l,3,5-triaza-
bicyclo[3.2.0]hepta-2,4-dione . . . . . .... 18

3 Nmr spectrum of the copolymer of divinyl ether and
4-phenyl-l,2,4-triazoline-3,5-dione . . . . .. 21

4 Nmr spectrum of the copolymer of divinyl ether and
4-methyl-l,2,4-triazoline-3,5-dione . . . . .. 22

5 Plot of M versus reaction time for EVE-PhTD in CH2,C
at 25C . . . . . . . . . . . 34

6 Nmr spectrum of 3-oxa-2,2-dimethyl-4-ethoxy-8-phenyl-
1,6,8-triazabicyclo[4.3.0]nona-7,9-dione . . . ... 38

7 Nmr spectrum of l-(formy]nethyl)-2-acetyl-4-phenyl-
1,2,4-triazoline-3,5-dione . . . . . . ... 49

8 Nmr spectrum of the Diels Alder, ene adduct of 4-phenyl-
1,2,4-triazoline-3,5-dione and styrene . . . ... 63

9 Nmr spectrum of the Diels Alder, ene polymer from styrene
and bis triazoline dione . . . . . . . .. 64

10 Plot of consumption of PhTD versus time for EVE-PhTD
in dioxane at 250C . . . . . . . .... ... 110

11 Logarithmic plot of [PhTD] /[PhTD or A /A versus time for
EVE-PhTD in dioxane at 25 .... . . . . 111









Abstract of Dissertation Presented to the
Graduate Council of the University of Florida in Partial Fulfillment
of the Requirements for the Degree of Doctor of Philosophy

POLYMERIZATION STUDIES OF
4-SUBSTITUTED-1,2,4-TRIAZOLINE-3,5-DIONES
AND
SYNTHESIS OF MODEL COMPOUNDS
RELATED TO TRIPLE STRAND POLYMERS

By

Sam Richard Turner

June, 1971

Chairman: Dr. George B. Butler
Major Department: Chemistry

The research described in this dissertation consists of two main

areas of investigation. The first area pertains to the use of azo

dienophiles, particularly 4-phcnyl-l,2,4-triazoline-3,5-dione, in

polymerization studies. The second area involves attempts to synthe-

size model compounds related to proposed triple strand polymers.



A. Polymerization Studies of 4-Substituted-l,2,/-triazoline-3,5-diones

The copolymerization and reactivity of the very potent cyclodien-

ophile, 4-phenyl-l,2,4-triazoline-3,5-dione (PhTD), with electron rich

coreactants were investigated. PhTD was found to spontaneously react

with vinyl ethers at room temperature in methylene chloride solution.

Ethyl vinyl ether (EVE) and isobutyl vinyl ether (IVE) were observed

to copolymerize spontaneously with PhTD to form 1:1 alternating co-

polymers. Divinyl ether (DVE) was observed to form a mixture of the

2+2 cycloadduct and copolymer at room temperature. At 60*C, only copol-

ymer was formed.

The structures of the copolymers were assigned from spectroscopic

and chemical data. Some physical property characterizations of the


vii








copolymers were made.

A propagation mechanism involving the coupling of dipolar inter-

mediates was ascertained as the most probable mechanism of polymeriza-

tion.. Numerous experimental observations were in support of this pro-

posed method of polymerization.

When the spontaneous copolymerizations of EVE and IVE were effected

in acetone or cyclohexanone, the corresponding 1,3,4-tctrahydrooxadia-

zine compounds were obtained as well as the expected copolymers. These

new heterocyclic ring structures were fully characterized. The com-

pounds were believed to result from an interception of the initial 1,4-

dipole intermediate by the weakly dipolarophilic alkyl ketone. DVE was

noted to form only a trace of the corresponding oxadiazine structure.

The difference in the reactivity of EVE and DVE was explained in

terms of the stability of the positive center of the 1,4-dipole.

Other olefinic compounds were reacted with PhTD. Vinyl acetate

was observed to undergo a unique intramolecular rearrangement of the

initially formed 1,4-dipole. Divinyl carbonate only resulted in 2:1

copolymers. N-vinyl carbazole spontaneously copolymerized to yield

a 1:1 copolymer of significantly higher molecular weight than obtained

in the vinyl ethers. The electron poor olefins, divinyl sulfone and

acrylonitrile, were found to be unreactive with PhTD.

Some decomposition reactions of PhTD were studied. Attempts to

catalytically homopolymerize PhTD were unsuccessful. The reaction of

PhTD with nucleophiles like sodium cyanide in dimethylformamide and

triethylamine resulted in the formation of 3,7-diphenyl-l,5-diazabicy-

clo[3.3.0]octa-2,4,6,8-tetraone as well as an unidentified oligomeric

product.







A new bis dionophile, 4,4'-(4,4 -diphcnylmethylene)-bis-l,2,4-

triazoline-3,5-dione, for use in cycloaddition polymerizations was syn-

thesized. It was found to spontaneously react with styrene to give a

high polymer believed to have been formed by first a Diels Alder re-

action and then an ene reaction.



B. Synthesis of Model Compounds Related td Triple Strand Polymers

Two dienes, 2-acetoxymethyl-l,3-butadiene and 2,3-di-(acetoxy-

methyl)-l,3-butadiene, were synthesized by a new sulfone pyrolysis pro-

cedure. The precursor acetoxy sulfones were prepared in good yields

from the corresponding bromides by use of silver acetate in acetonitrile.

The Diels Alder reactions of these acetoxy dienes and the corresponding

dihydroxy diene from the 2,3-diacetoxy diene were studied with p-benzo-

quinone. A facile aronatization or dehydrogenation of the adduct, de-

pending on the conditions, precluded its isolation.

2-Cyclohexene-l-one was found to react sluggishly with the 2-

acetoxymethyl diene. Attempts to force the reaction yielded polymeric

materials. Diazoquinone reacted with the disubstituted dienes to yield

the expected Diels Alder adducts. Various attempts at catalytic hydro-

genation of these adducts were not successful.

Tetracyanoethylene was found to be unreactive with a-pyrone.

Fumaronitrile and p-benzoquinone resulted in the expected adducts.

Bromination of 3,4-dimethylbutadiene sulfone and then dehydro-

bromination resulted in the corresponding 3,4-dimethylthiophene-l,l-di-

oxide. This compound was found to be unreactive with tetracyanoeth-

ylene, but it gave a double Diels Alder adduct with maleic anhydride.















CHAPTER I

Introduction

A. Polymerization Studies of Azo Dienonhiles

Reactivity of azo dienophiles

Compounds containing dienophilic nitrogen to nitrogen double bonds

have been extensively studied as reactants in cycloaddition reactions.

Normally these azo compounds have been shown to be more dienophilic

than their carbon counterparts. For example azodicarboxylates, 1, have

a stronger dienophilic reactivity than the corresponding fumarates, 2.1


N ,NC02R H CO R
RO2C 2 RO2C H

1 2

However, at the time this research was initiated only one report of the

use of these compounds as monomers in polymerization studies was

recorded.2 This account involved the copolymerization of ethyl azo-

bisformate with the comonomers tetrafluoroethylene, acrylonitrile and

methyl methacrylate. In each case some incorporation of the azo com-

pound into the polymer was verified by elemental analysis. No other

structural characteristics were reported.

4-Phenyl-l,2,4-triazoline-3,5-dione (PhTD), 3, has been shown by

Sauer and Schroder to be the most reactive of the azo dienophiles and

perhaps the most reactive dienophile known. The authors compared the

reactivity of PhTD with tetracyanoethylene by utilizing competition

experiments with 2-chloro-l,3-butadiene. PhTD was observed to react









about one thousand times faster than tetracyanoethylene, which had been

previously described as one of the most potent dienophiles synthesized.4

With the same diene,maleic anhydride, 4, was found to react only about

one half as fast as the tetracyanoethylene. Hoi.ever, with other

dienes tetracyanoethylene reacted as great as 106 times faster than 4.



Copolymerization studies

The structure of 4-substituted-l,2,4-triazoline-3,5 diones is very

similar to that of the carbon to carbon double bond dienophiles maleic

anhydride and N-substituted maleimides, 5. The latter compounds have

been utilized extensively as comonomers in copolynerization studies.

It was expected, then, "a priori" that these nitrogen analogues of maleic
H H H H
N--N Cb C /C'

0 ) 0 KA '0 0 Z0
Phl R

3 4 5

anhydride and the maleimides would undergo similar copolymerizations

with the appropriate electron rich comonomer.

Cyclocopolymerization, originally reported by Butler,6 has evolved

as an extremely important research area in polymer chemistry, not only

because of the theoretical significance of the reaction but in the main

because some of the cyclocopolymers have been shown to be active anti-

tumor agents. Because of this importance, the mechanistic and prepar-

ative aspects of cyclocopolymerization have undergone a careful system-

atic study. The general mechanism proposed was that of an alternating

intra-inter molecular propagation6 as shown below for the divinyl ether-

maleic anhydride system which is the most thoroughly studied of all the








cyclocopolymerization-systems. Since the initial mechanistic proposal,

evidence consistent with the participation of a donor acceptor complex




0 R 0
R-' R '











R 00 0


0-- ( ,) Z: 0V O





as a comonomer has been presented.8 More recently the divinyl ether

maleic anhydride system has been observed to polymerize thermally in

the absence of a free radical initiator and this has been interpreted

as additional evidence for the participation of a donor acceptor

complex in the copolymerization.

Since 4-substituted-1,2,4-triazoline-3,5-diones are known to be

better dienophiles than the usual electron poor comonomers in cyclo-

copolymerization, it was thought that they might behave as electron

acceptors in the presence of electron rich 1,4-dienes and participate

in cyclocopolymerization. Furthermore, it seemed a distinct possibility,

because of their great reactivity, that a spontaneous cyclocopolymer-

ization might possibly be triggered.

The degradation approach to proving polymer structures is important.








For example, the cyclic structure resulting from the copolymerization

of diallyl quaternary aamronium salts was verified by the following

degradation procedure.10



C -1. to hydroxide 31. 1E I (CH3) N
+ -2. to hydroxide
NBr 2. heat 3. heat
C!3 CH3 crosslinked
H3 3 C3 3 polymer
r J n



No such proof of the cyclic structure of the cyclocopolymer

systems has been possible to this time. If a 2:1 cyclocopolymer were

to form, the unique characteristics of the triazoline dione moiety

would offer a convenient handle to chemically probe the polymer

structure by the general degradation procedure shown below.



O0- --N-N--
N-N N
O N 0 base H H N2

Ph H/
0H low molecular
N weight products
ih
SL -rn

For the preceding reasons,as well as the desire to build new

cyclic copolymer structures to be tested as anticancer agents, the

behavior of 4-substituted-l,2,4-triazoline-3,5-diones with electron

rich olefins was investigated.



Nitrogen backboned polymers

At the commencement of this research no nitrogen backboned polymer

had ever been reported. If homopolymerization of an azo dienophile







could be effected through the nitrogen to nitrogen double bond,
obviously such a polymer with a nitrogen backbone would result. A
report by Iuisgen of the participation of ethylazobisformate in a
substitution reaction with fluorene proceeding by a free radical chain
mechanism made a free radical polymerization of such an azo dienophile
an attractive possibility.


12 --- 21.


SH

+ R~N-N\R





SN-N PH
R R


(-+ IH

H R= --CO2C2CH3


@~ 0)0
H /N-<
R R

SYNH
i-


By envisioning the results of such a successful polymerization
of a 4-substituted-l,2,4-triazoline-3,5-dione, one would have at hand
structure 6. Since such structures are readily hydrolyzable in strong


-NN

K t 6


base, a polyhydrazine structure, 7, would be distinctly possible.
These nitrogen backboned structures might possess practical value as
well as, assuredly, possessing theoretical importance. As another



K- r 7








goal of this research, the homopolymerization of 4-substituted-1,2,4-

triazolinc-3,5-diones, was investigated.

In the course of this work, Pirkle and Sticklerl2 reported the

homopolymerizarion of 4-n-butyl-l,2,4-triazo'ine-3,5-dione by initiation

with visible irradiation. These authors presented strong evidence that

the polymer obtained, indeed, possessed a nitrogen backbone.



Dials Alder polymers

Although the number of chemical reactions investigated in organic

chemistry is irmense, those that have been successfully adapted to

yield high polymers are few. Two types of cycloaddition reactions

have met with considerable success in producing high polymers, i.e.,

1,3-dipolar cycloadditions3 and Diels Alder reactions.14

The Dials Alder reaction has developed into the most profitable

application of the use of cycloaddition reactions to form polymers.4

To adapt the Diels Alder reaction to a polymer forming system whereby

the polymer is built up by stepwise Diels Alder cycloadditions requires

that the reactants be made difunctional. Two different approaches

have been utilized. The first involves the reaction of a bis diene

and a bis dienophile, generally referred to as an A-A, B-B system. One

example5 is the reaction of p-benzoquinone, 8, with the acetal prepared

from 2-hydroxymethyl-l,3-butadiene and acetaldehyde, 9.





Co H CH-2 O
-C 0









The second general approach has utilized an A-B monomer or an

intramolecular dicne, dienophile. The reaction of the substituted

Ct-pyrone, 10, and p-phenylene bismaleimide, 11, is a good example of

this approach.16

0 i0 00



00 0 0

10 11
F 0 0 -

CHR -R I ---- polymer
q__. C O-- R -NI
A H 3 Ci2 0
L 0 0



The main limitation and drawback to the use of the Diels Alder

reaction has been the difficulty in obtaining high molecular weight

products. In a polymerization propagation that follows step growth

kinetics, as is the case in a Diels Alder polymerization,7 the degree

of polymerization DP follows the Carothers equationl8 DP = 1/l-p,

where p is the extent of reaction. This means that the reaction must

be practically quantitative before a high molecular weight product is

obtained. For example a reaction with a 98% conversion only yields

a DP of 50 or, in other words, a low average molecular weight.

Hence, any stepwise polymerization reaction that is subject to

side reactions of any significance will not be suitable for formation

of high molecular weight products.

Two main reasons have been put forth for the inability, in most

instances, of Diels Alder polymerizations to achieve high molecular

weights.19 The first involves the ease by which the retrodiene








reaction can occur and the second concerns the chain growth of the

diene under the reaction conditions. Another complicating factor in

some systems has been the precipitation of the rigid ladder type polymer

causing a premature termination.15

Since the Dials Alder reaction is a thermally catalyzed reaction

and these two complicating factors also are enhanced at higher temper-

atures, it is not surprising that the problem of obtaining high

molecular weight has plagued its use in producing high polymers.

Stille20 and coworkers have successfully circumvented the retro-

diene reaction by employing bis dienes such as bis a-pyrones and his

cyclopentadienones that lose carbon dioxide or carbon monoxide respec-

tively and hence prevent the degradative retrodiene reaction from

occurring. An example has been the successful use of 3,3'-(oxydi-p-

phonylene)bis(2,4,5-triphenylcyclopentadienone), 12, and p-phenylene

bismaleimide, 11.20 A polymer with an intrinsic viscosity of 1.01

was obtained in four hours in refluxing 1,2,4-trichlorobenzene.


Ph

O -0 + 11
r-'
Ph
12 2

0 Ph Ph 0
S ----Ph -- Ph


0 Ph Ph 0



Another possible route to circumvent the bothersome side reactions

would be to employ extremely reactive reactants that would not need to









be heated in order to obtain the necessary high conversions. Obviously,

a bis 1,2,4-triazoline-3,5-dione would be expected to serve in this

capacity because of its fantastic reactivity. Hence another objective

of this research was the synthesis, and polyn:erization with bis dienes,

of such bis dienophiles.



B. Triple Strand Polymer Model Compound Studies

Thermal stability of ladder polymers

The synthesis and study of thermally stable polymers have been

extremely active areas of polymer chemistry research in recent years.

The extensive accounts cf such research recorded in the chemical

literature attests to the theoretical and practical importance of this

work. No attempts will be made to review these accounts since a recent

book1 and several reviews222324 are readily available.

Physical polymer properties have generally been found to be

related to the molecular weight of the polymer. These structure-

property correlations have established that polymers with ladder or

double strand structures, 14, possess extremely high thermal stability.23

For example polydiallydiphenysilane, having structure 13 was observed

to have enhanced thermal stability over its non-cyclic counterpart








Sir
HC \C6H5 n
5 6 6 -13
25
prepared from the monoallyl derivative.. The reason advanced for the

thermal stability of such cyclic structures is that thermal bond








cleavage which occurs -within the cyclic polymer repeat units of the

backbone does not lead to a lower molecular weight polymer. It is

obvious that thermal bond cleavage in the non-cyclic structures results

in a lower molecular weight as depicted in 14a and 14b.




14a 14b

Therefore one goal that the polymer architect has striven for in

the design of materials possessing thermal stability has been the

synthesis of ladder or double strand polymers. Needless to say, many

different researchers have been successful in using the double strand

polymer concept in preparing materials resistant to thermal breakdown.


Possible triple strand polymers

As an extension of the ladder polymer concept of thermal stability

a triple strand polymer would be expected to possess thermal properties

reflected from a structure that requires three bond cleavages per ring

to cause a decrease in molecular weight. Two possible approaches to

constructing such a polymeric species are: 1) a formation of a tubular

polycyclohexane, 15, from a triply initiated chain reaction of benzene





1000-


15

and 2) a triple 1,4-polymerization of a monomer such as 16 to yield

structure 17.
















16 17



Model compound studies

Generally, one of the objectives of this research was the

preparation and studies of model compounds related to these two

possible routes envisioned to triple strand polymers.

Much effort has been extended in the attempted synthesis of

tetracyclo[4.4.0.13'9.1 4'8dodecane, 18, the repeat unit of the

tubular polycyclohexane polymer.






18

The first approach has involved the homo Diels Alder reaction of

cis 4,5-diallylcyclohexene derivatives, 19.26a To date this approach

has not been successful.



jI- 1_88



19

The second approach has utilized 1,3,5-trisubstituted cyclobexane







derivatives 20 and 21. The tri ester 21 has been successfully prepared

26b
and failed to undergo the desired cyclization to 18. A compound,

which would lead to a nitrogen analogue of 18, 22, has been successfully

prepared but also failed to yield the cyclic structure 23.27




SF 18


20



R e 4 0 e R= -CHC02C2C H CH
base 2 2 2 3


18
\0
21

0
0 -N



O0CPNhIh NZOC :==0 _'0


22 23

The synthesis of compounds such as 24, which are functionally

capable of undergoing an intramolecular base catalyzed cyclization, is

the basis of the third approach to 18. One objective of this work





S 2CH s 2


24

was the preparation of compound 24, and other related structures as 25,

and cyclization of them to their respective cage structures 26.








0
H20Ms base




25 26

A fourth approach to 18, which was also studied as a part of this

research, was the possible intramolecular Diels Alder reaction of 28

to 18. A route to 28 was envisioned by the well documented 1,4-

elimination of bromine by zinc in dimethylformamide28 of 27,29 the

Diels Alder adduct of p-benzoquinone and 2,3-di(bromoethyl)-l,3-buta-

diene.
0.
0 0



0 2


27 28

In order for a monomer like 16 to be polymerizable by a triple

1,4-initiation it is immediately obvious that monomers such as 29 and

30, which are steric models for 16, would have to be subject to a 1,4--

polymerization. Hence another objective of this research was the

synthesis of 5,5,6,6-tetrasubstituted cyclohexadienes like 29 and 30

and the study of their polymerizations.




CN


29 C 0 H3
N CN 0/ CH3

29 30 CH 3














CHAPTER II

Polymerization Studies of 4-Substituted-1,2,4-triazoline-3,5-diones

A. Copolymerization of Ethyl Vinyl Ether and Diviny Ether with

4-Phenyl-l,2,4-triazoline-3,5-dione

Structure of the copolymers

4-Phenyl-l,2,4-triazoline-3,5-dione (PhTD), 3, spontaneously

copolymerized with ethyl vinyl ether (EVE) in methylene chloride

solution at room temperature and the product was shown to have a 1:1

composition by elemental analysis and nmr analysis. The copolymer was

found exclusive of any 2+2 cycloadduct (1,2-diazetidine), 31a.



a: R= -CH2CH3
H2C--CH-O-R
I b: R= -CR=CH2

0 =Z3 ) 0
Ph

31

Cycloadditions of ethyl azobisformate, 32, a similar azo dienophile,

have been shown to occur through both nitrogen to give 1,2-diazeti-

dines, 33, or through one nitrogen and one carbonyl oxygen to give

oxadiazines, 34. Therefore, structure 35, where propagation occurred

through one nitrogen and one carbonyl oxygen, and structure 36, where

propagation takes place through the nitrogen to nitrogen bond, appeared

to be the most likely candidates for the structure of the copolymer.

The nmr spectrum (Fig. 1) did not distinguish between the two













N
\ N 20_2CR R02 C N- N O2R
NZN 2 2
\ 2W C 33
2 32



RO2C-N 0
'OR

34

possibilities since the observed resonance signals were consistent

with either structure. The signals were 67.50 (broad, aromatic

hydrogens, 5), 66.05 (broad, hydrogen adjacent to two electronegative

atoms, 1), 63.90 (broad, methylene hydrogens of ether, 4) and 61.20

(broad, methyl hydrogens of ether, 3).



CH- CHI


i- 2
Ph CH Ph
CH3 n-



35 36

The infrared data, however, indicated that 35 was the predominant

repeat unit of the copolymer structure. A strong 1610 cm.1 absorbance

was observed and it was assigned to the -C=N- chromophore which is

only present in 35. Oxadiazine structures like 34 have exhibited
-I
absorbances in the 1630-1680 m.-1 region and they were assigned to

the -C=N- chromophore.30 A recent report on the infrared spectrum of
-l
N-cyclohexylacrylaldimine, 37, has assigned an observed 1608 cm.-

band to the -C=N- chromophore.31 Stickler and Pirkle12 synthesized
Stickler and Pike synthesized








































I I I I I
7.0 6.0 5.0 4.0 3.0 2.0 1.0
PPM (6)

Figure 1. Nmr spectrum of the copolymer of ethyl vinyl ether and 4-phenyl-1,2,4-triazoline-3,5-dione.











CDC
CC :C=N_




37

38, 39 and 40 as model compounds in a recent study of the homopolymer-

ization of triazoline diones. A strong 1605 cm.-i absorbance was

observed in 38 and not in 39 and 40.



C 11 C6 H CH C6 11 H
00 3 1 3

o0mQ -OCHi3 o0 300o),
N NN
CH3 CH3 CH3


38 39 40

Neither PhTD nor its precursor 4-phenyl urazole had an infrared
-1
absorbance in the 1610 cm.1 region. This information, along with

that obtained from the model compounds, appears as solid evidence for

the assignment of 35 as the predominant repeat unit of the copolymer.

In contrast to the EVE system, divinyl ether (DVE) and PhTD were

observed to form a mixture of copolymer and an adduct at room temper-

ature in methylene chloride. When the reaction was done at 60C only

copolymer was isolated.

The adduct from the room temperature reaction was isolated in pure

form and was assigned as the 1,2-diazetidine, 3-phenyl-6-vinyloxy-1,3,5-

triazabicyclol3.2.0]hepta-2,4-dione, 31b. The infrared spectrum gave
-l
no 1610 cm. absorbance, but gave strong vinyl ether absorbances at

1645 cm.- and 1625 cm. The nmr (Fig. 2) spectrum gave resonance



























0o










I I i 1 I

7.0 6.0 5.0 4.0 3.0 2.0 1.0
PPM 2,)

Figure 2. Nmr spectrum of 3-phenyl-6-vinyloxy-1,3,5-triazabicyclo[3.2.0]hepta-2,4-dione.








signals at-67.40 (singlet, aromatic hydrogen, 5), 66.60 (quartet,

vinyl hydrogen, 1), 65.90 (triplet, hydrogen next to vinyloxy on ring,

1), 64.50 multiplee, vinylic and ring methylene hydrogens, 4). The

mass spectrum yielded the correct molecular ion and the elemental

analysis agreed with the calculated value.

On warming an unpurified mixture of polymer and adduct to 600C,

a ring opening polymerization occurred. This was noted by the

disappearance of the 65.90 triplet in the nmr spectrum and the formation

of a product which gave identical spectral data as the original 60C

copolymer.

An elemental analysis of the copolymer was indicative of a 1:1

structure and for such a copolymer three structures were probable. The

first two, 41 and 42, were analogous to the EVE case in which only one

double bond is consumed and the third, 43, was precedented by cyclo-

copolymerization in which both double bonds are consumed.





N-N F7N-N --CH-CH-
0= -0Gl-CH-- O .:O0 9
N P N

CHC
Ph OH Ph 2
CH2 n 42 J
41









On the basis of spectroscopic and chemical evidence, repeat unit

41 appeared to predominate. First, the ab:senice of upfield resonances

in the nmr spectrum indicated that there were no methylene units

flanked by saturated carbon atoms. Since a requirement for the cyclic

structure 43 would be upfield resonances, this structure was eliminated.

The resonance signals observed (Fig. 3), 67.48 (broad, aromatic

hydrogens, 5), 66.30 (broad, vinylic hydrogen and hydrogen adjacent to

two heteroatoms, 2) and 64.20 (broad, methylene and vinyl hydrogens, 4),

were consistent with both structures 41 and 42.

The infrared spectrum of the copolymers, as in the EVE copolymers,
-i
showed a strong 1610 cm.- band and this was assigned to the -C=N- unit.
-I
Also present in the infrared spectrum were bands at 1640 cm. and
m-1 32'33
860 m.-1 due to the vinyl ether chromophore.3233
-1
As insurance that the 1610 cm. band was not associated with

the aromatic moiety, a copolymer of DVE and 4-methyl-l,2,4-triazoline-

3,5-dione was prepared. This copolymer also exhibited the strong
-i
1610 cm. absorbance. The nmr spectrum of this copolymer is given

in Fig. 4.

Catalytic hydrogenation of the DVE copolymer over palladium on

alumina at atmospheric pressure resulted in the absorption of the

theoretical amount of hydrogen for a structure like 41 or 42. The
-i
resulting material exhibited a new 2770 cm.- band due to the saturated

carbon hydrogen stretch, and loss of 1640 cm.- and 860 cm.- bands
-i
of the pendant vinyl group in the infrared spectrum. The 1610 cm.

band also disappeared. New resonances appeared in the nmr spectrum

at 63.90 and 61.20. These signals had the same chemical shifts as

the ethyl protons in the EVE copolymers.









































I I I I I I
7.0 6.0 5.0 4.0 3.0 2.0 1.0
PPM (6)
Figure 3. Nmr spectrum of the copolymer of divinyl ether and 4-phenyl-l,2,4-triazoline-3,5-dione.










































I I I I I I I I
7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0
.PP (6)

Figure 4. Nmr spectrum of the copolymer of divinyl ether and 4-nethyl-1,2,4-triazoline-3,5-dione.









One discrepancy in the hydrogenation results was the disappearance
-l
of the 1610 cm. band in the infrared spectrum. This was thought to

be due to an isomerization over the alumina catalyst for the following

reasons. The -C=N- linkage has been shown to be resistant to

catalytic hydrogenation30 when it appeared in oxadiazine structures

like 34. The catalytic hydrogenation of the EVE copolymer was carried

out as a control and although no hydrogen was absorbed, the loss of

the 1610 cm.-1 band was noted. A plausible explanation is that the

catalyst promotes an isomerization from structure 35 to the structure

bonded through both nitrogens, 34. If this were the case, a decrease

in the molecular weight of the copolymers should be observed since

such a change would require bond breaking and then bond reformation.

This was exactly what was observed as a DVE-PhTD copolymer had a

molecular weight of 1590 before hydrogenation and 490 afterwards. An

attempt to use palladium on carbon as the catalyst only gave a

partial hydrogenation.



Physical characteristics of the copolymer

The copolymers of EVE-PhTD and DVE-PhTD were white, highly

electrostatic solids which were soluble in most organic polar solvents.

Maximum number average molecular weights (M ) were normally in the

1000 to 3000 range and were measured by vapor pressure osmometry CVPO)

in acetone solution. The polymeric materials were low melting and

both copolymers softened around 100-110C.

A molecular weight distribution (Mw/Mn) of 3.36 was obtained for

one DVE-PhTD sample from gel permeation chromatography CGPC). The

determination was made in dimethylformamide and a calculation of the









M from the GPC trace gave a value of 2500 versus 2750 from the VPO.
n
An attempted GPC analysis of an EVE-PhTD copolymer was unsuccessful due

to what was believed to be a degradation of the polymer in the highly

polar solvent.



Spontaneous copolymerizations

Since the copolyrnerization of EVE and PhTD was certainly a

spontaneous copolymerization, the literature was reviewed to obtain

examples of previous spontaneous copolymerizations. Spontaneous

copolymerizations are differentiated in this discussion from other
34
types of photoinitiated spontaneous copolymerizations and Lewis acid

catalyzed spontaneous copolymerizations35 by defining a spontaneous

copolymerization as one that occurs when two olefinic monomers are

mixed in bulk or in solution at room temperature or lower with no

additional initiator involved.

All observations of spontaneous copolymerizations reported in

the literature have involved an olefinic monomer pair in which one

partner was electron rich and the other electron poor. Apparently,

the first report of such a copolymerization was disclosed in a

Canadian patent authored by Miller and Gilbert.36 They reported the

spontaneous copolymerization of vinylidene cyanide and alkyl vinyl

ethers. No mechanistic interpretation of their results appeared.

Yang and Gaoni37 have prepared 1:1 copolymers from the spontaneous

reaction of trinitrostyrene, 44, as the acceptor or electron poor

olefin and either 4-vinyl pyridine,45, 2-vinyl pyridine or p-dimethyl-

aminostyrene as the donor or electron rich olefin. The authors

suggested that the monomers formed an initial donor acceptor complex














+ 6 copolymer


45 44
which initiated the radical copolymerization of the monomers.
38
Kosover38 has suggested that the copolymerization is initiated by

the formation of a ground state donor acceptor complex which goes

to an excited ion pair state which then copolymerizes the surrounding

ground state donor acceptor complexes according to the equation shown

above. Such a mechanism is designated by Kosower to be a "T-Class

Reaction" in which the electron transfer in the complex is brought

about by thermal energy. The general equation38 for this reaction,


r D--A-

DAtz ( (DA A.) D +A



L "D-A-


proposed by Kosower, includes formation of a ground state complex (D,A)

which experiences a thermally induced electron transfer to the excited

ion pair form CD., A.) and then can go to products or can disassociate

to the separate ion pair excited state.

Butler and Sharpe939 have reported two other systems which fit

the definition of spontaneous copolymerization. One system in which

this type reaction occurs is the cyclocopolymerization of maleic








9
anhydride and DVE, and the other is the cyclocopolymerization of

divinyl sulfone and DVE.39 Both systems are believed to form a

donor acceptor complex which then goes to an excited state, couples

to form a diradical and thus initiates the copclymerization of

either completed or uncomplexed comonomers.



Mechanism of EVE and DVE copolymerizations

PhTD has been shown to undergo 2+2 cycloadditions with both

indene and p-dioxene.0 The cycloaddition with indene has been show,

to involve a dipolar intermediate since this 1,4-dipolar species has

been trapped with water. p-Dioxene formed the expected 2+2 adduct

plus a lot of discarded polymeric material.

In light of these results and in light of the polymer structures,

the most plausible propagation mechanism is believed to be the initial

formation of a stable 1,4-dipole. This intermediate, in the EVE

system, then went directly to copolymer, while in the DVE system it

formed the 1,2-diazetidine 31b and copolymer. At 600C, the diazetidine

is proposed to open to the initial 1,4-dipole and couple intermolecular-

ly to form the copolymer 41.

The difference in behavior between the EVE and DVE systems can

be rationalized in terms of the stabilities of the positive centers

of the respective 1,4-dipoles. The acid hydrolysis of EVE has been

observed to be 350 times faster than the acid hydrolysis of DVE.40

This difference is due to the stability of the corresponding oxonium

ion intermediates, 47 versus 48. The same positive center stabilization

occurs in the two 1,4-dipoles. Therefore it is believed that the more

stable 1,4-dipole (EVE) has a more pronounced dipolar character and









+ +
00 C/ 0 OCH2 H C
3


47' 8

links intermolecularly, while the energetically higher DVE dipole

closes to the strained 1,2-diazetidine.

The exact nature of the transition state leading to the 1,4-dipole
38
is not known. Kosower has proposed that 2+2 cycloadditions which

are dipolar in nature are "T Class Reactions"and they go through an

excited charge transfer complex which then couples to the corresponding

dipolar species. This dipole then closes to a four membered ring.

The formation of the vinyl ether-PhTD intermediate 46 by this pathway

is shown below.












The other possibility is an electrophilic attack of the electron

poor PhTD on the electron rich olefin in which no complex is required

to arrive at 46,i.e.,

0 R
__/ CH- 0 R
CH

N N- N-

Ph Ph









The first observation that is consistent with the postulated

1,4-dipole is the non-cyclic structure of the DVE--PhTD copolymer. A

diradical intermediate would have been expected to cyclize. However,

cyclization of the 1,4-dipole 46 would be highly unlikely since vinyl

ethers are known to be resistant to anionic attack.

Copolymerizations of the two vinyl ethers with PhTD were found

to be insensitive to a free radical inhibitor and a free radical

initiator. The free radical initiator azobisisobutyronitrile (AIBN)

had no effect on the molecular weight of the EVE copolymers (Table 1,

exp. 11). The copolymer from the DVE case showed some increase in

molecular weight, which some random coupling of pendant vinyl groups

could easily explain (Table 2, exp. 3). The known free radical

inhibitor, m-dinitrobenzene, had no effect on the copolymerization

of DVE (Table 2, exp. 6).

An attempt to free radically copolymerize DVE and PhTD at -45C

by photolytic decomposition of benzoyl peroxide only resulted in a

product identical to the ambient copolymerizations. Since the conversion

was extremely low, the product was probably the result of a slow thermal

reaction, because at the same temperature the same product was obtained

without benzoyl peroxide.

In an attempt to exclude moisture from the system, a copolymer-

ization of DVE and PhTD was effected under more rigorous conditions

than the normal trials. It was felt that since water would terminate

the dipolar step-growing chain that the elimination of moisture would

lead to a higher molecular weight copolymer. The dry conditions

included flame drying of glassware, predrying of monomers and transfer-

ing monomers and solvents in an inert and dry atmosphere. Although










TABLE 1. COPOLYMERIZATIONS OF EVE AND PhTD


Exp. Reaction Conditions


No. Solvent Temp.
oC

1 CH2C12 25


2 CH2C2 25


3 CH2C12 25


4 CH2C12 25

5 CI2C12 25

6 CH2C12 25

7 CH2C12 25


8 C CH2C12 60
9d

10 CH2C12 60


11e CH2C12 60


Time
(hr.)

0.5


0.03


0.25


1.0

4.0

12.0

24.0


24.0



24.0


24.0


Product and
conversion


87.5
1:1 copolymer

52.0
1:1 copolymer

75.7
1:1 copolymer







77.0
1:1 copolymer





77.4
1:1 copolymer

78.2
1:1 copolymer


Sa IR
n 1610 cm.


1660 s


410


670 s


1175 s

1340 s

1260 m

437











1 (continued).


Exp. Reaction Conditions Product and
No. Solvent Temp. Time Conversion
"C (hr.)

12 DMF 25 0.5 50.3
1:1 copolymer

13 THF 25 0.5 85.6
1:1 copolymer

14 THF 25 0.5 67.0
1:1 copolymer

15 CH2Cl2 60 118 71.5
1:1 copolymer

16 CH2C12 60 166 77.5
1:1 copolymer

17 CH2Cl2 60 211 76.2
1:1 copolymer


aVPO-acetate solution.
b
s, (strong); m, (medium); w, (weak); -, (not present).

CSample 1 dissolved and heated.

Sample 1 hydrogenated.

0.5 wt. % AIBN added.

10 mol. % NaPh4B added.


a
n


3900


940


2040


923


1120


970


TABLE~


IRb

1610 cm.


s


s


s


w


w


w










TABLE 2. COPOLYMERIZATIONS OF DVE AND PhTD

Exp. Reaction Conditions Product and a
No. Solvent Temp. Time Conversion n
C (hr.) 1610


1 CH2C12 25 0.5 77.5 450 w
1:1 copolymer

2 CH2C12 60 24 77.8 860 s
1:1 copolymer

3c CH2Cl 60 24 80.8 1590 s
1:1 copolymer

4 CH2C12 60 120 84.5 3130 s
1:1 copolymer

5d CH2CI2 60 24 86.0 2540
1:1 copolymer

6e CH2C12 60 24 65.8 2130 s
1:1 copolymer

7 CH2C12 60 120 85.8 2760 s
1:1 copolyner

8 CH2C2 25 22 85.7 w
1:1 copolymer
and adduct

9 Dioxane 60 24 66.4 1330 s
1:1 copolymer


IRb-
(cm. )
1640

m


m m


m m


m m












Exp. Reaction Conditions
No. Solvent Temp. Time
C (hr.)


DMF

DMF

CH3CN

CH3CN


24

24

24

0.5


TABLE 2 (continued).

Product and
Conversion



31.2

19.4

80.0

73.8


Ta IR
n (cm. )
1610 1640 860


VPO-acetate solution.
b
s, (strong); m, (medium); w, (weak); -, (not present).

C0.5 wt. % AIBN added.

Dry conditions.

el m-dinitrobenzene added.

Polymer 6 hydrogenated.









a higher molecular weight material was obtained than in the normal

trials, a control in which the glassware was not treated yielded even

higher molecular weights (Table 2, exp. 7 vs. exp. 5).

Szwarc41 has discussed in great detail the effect of trace amounts

of water on ionic polymerizations and the conditions needed to conduct

polymerizations in the absence of water and other impurities. Since

the purification procedures needed for such experiments required

special techniques and equipment, this approach was abandoned.

Surprisingly, the EVE-PhTD copolymerization conducted at 60C

resulted in a lower molecular weight product than in the room tempera-

ture trials. The 1610 cm.-1 band in the infrared spectrum of the

copolymer was absent, although the nmr spectrum was the same. The

elemental analysis remained consistent with a 1:1 copolymer. The room

temperature copolymerization was repeated for a 24 hour period and a

molecular weight of 430 was obtained compared to 2440 for a thirty

minute polymerization time. The 1610 cm.- infrared band was absent

in the product from the 24 hour run. A study of molecular weight

versus time was conducted for the room temperature copolymerization

and the results are shown in Fig. 5. A decrease in intensity of

the 1610 cm.-1 band paralleled the decrease in molecular weight.

Table 1 gives the molecular weight versus time in tabular form. Co-

polymerizations conducted at 600C for extended times showed a rebuild-

ing of the chain length (Table 1, exps. 15, 16 and 17).

These results can easily be accommodated by the proposed copolymer-

ization mechanism. The decrease in molecular weight is believed to

result from a depolymerization back to the 1,4-dipole structure and

then recombination through both nitrogen to give structure 36,















1 20-

12000

Mn
800-







200Li


2 4 6 12 22 24
REACTION TIME (HOURS)
Figure 5. Plot of Mn versus reaction time for EVE-PhTD in CH2Cl2 at 25C.









possibly a more stable structure. The DVE copolymer once formed was

observed to be thermally stable at 60"C as noted by no decrease in

molecular weight or decrease in the intensity of the 1610 cm.-1 absorb-

ance. Since the activation energy to reformation of the vinyloxy 1,4-

dipole would be expected to be higher than the ethyloxy because of the

difference in stability of the positive center, this result is also

consistent with the polymerization mechanism.

It is generally thought that dipolar reactions should show pro-

nounced solvent effects. The results of a solvent study of the reaction

rate are shown in Table 3. This study was conducted by observing the

disappearance of the band in the visible spectrum of the PhTD. No

pronounced rate differences were observed in going from the fairly

non-polar solvent benzene to the strongly polar solvents dimethylform-

amide and acetonitrile. There was a distinctive rate difference between

EVE and DVE. This was probably another manifestation of the difference

in the stability of the positive center of the dipole.

Gompper42 has recently reviewed cycloaddition reactions involving

polar intermediates. He cites two cases in which significant solvent

effects may not accompany such reactions. The first case involves

reactants that are highly polar and thus experience significant solvation

effects to effectively negate the solvation of the intermediate. The

second case involves a system where the energies of activation of the

first step and the second step are nearly the same and a change in

solvent changes the rate determining step, but not necessarily the

overall reaction rate.

Since both monomers are highly polar molecules, it is reasonable

that they could experience enough ground state solvation to effectively

cause the solvation of the intermediate to be undetectable.








One criterion which can conclusively demonstrate the presence of

a dipolar intermediate is the interception of this intermediate before

cycloproduct formation.4 When EVE and PhTD were reacted at room

temperature in acetone 3-oxa-2,2-dimethyl--4-ethoxy-8-phenyl-1,6,8-

triazabicyclo[4.3.0]-nona-7,9-dione 49,was formed in 42% yield. Along

with this product was formed a copolymer which from the nmr spectrum

appeared to have about 12% acetone incorporated.

This result is believed to be conclusive evidence for the existence

for the 1,4-dipole since the product arises from the interception of

the 1,4-dipole with the weakly dipolarophilic acetone. Apparently some

/OCI2CH3
2OC 2CH3 CH--0
CH


CH2 OC N 3-A CH3
N- CH --- \
3 0= < o
0-( ^N
N Ph
Ph H OCH C 49
12 2 3


o -N CH3
N N 3


Ph
terpolymer
and/or

/CH-O-CH2CH3
C2 0-
N-N- CCH3
S'C3

N
Ph

of the intercepted dipole did not close to the six membered adduct but

proceeded to link intermolecularly with other similar segments or with

other 1,4-dipoles to form the copolymcr containing about 12% acetone.









TABLE 3. FIRST ORDER RATE CONSTANTS IN PhTD AT 25C


A. Ethyl Vinyl Ether-PhTDa

Solvent k(sec)-l (D)

Acetone 5.36 x 10-2 20.7
-2
Dimethylformamide 6.02 x 10- 37.6
-2
Dioxane 6.83 x 10- 2.2

Acetonitrile 2.22 x J0-1 37.5

Methylene chloride 6.04 x 10-1 9.1
-l
Benzene 2.85 x 10-1 2.3


B. Divinyl Ether-PhTDa
-3
Dioxane 3.05 x 10-3 2.2

Acetone 1.13 x 10-2 20.7

Methylene chloride 4.20 x 10-1 9.1


al0:1 vinyl ether to PhTD





The infrared spectrum of 49, which is a new 1,3,4-tetrahydrooxa-
-l
diazine ring structure, showed strong absorbances at 2980-2880 cm.-

(saturated carbon hydrogen), 1770 and 1710 cm.-I (double carbonyl) and
-i
strong bands in the 1200-1000 cm.1 region due to the acetal linkage.

The nmr spectrum (Fig. 6) gave resonance signals at 67.40 multiplee,

aromatic hydrogens, 5), 65.02 (quartet, hydrogen on acetal carbon, 1),

63.73 multiplee, methylene hydrogens, 4), 6.1.85 (two equivalent

singlets, nonequivalent methyl hydrogen from incorporated acetone, 6)

and 61.25 (triplet, methyl hydrogens from ether, 3). The elemental

analysis agreed with the calculated value.










































8.0 7.0 6.0 5.0 4.0 3.0 2.0. 1.0

PPM (6).

Figure 6. Nmr spectrum of 3-oxa-2,2-dimethyl-4-ethoxv-8-phenyl-l,6,8-triazabicyclo[4.3.0]nona-7,9-dione.








In previous studies42,43,44 of the 1,4-dipoles, many different

reactive dipolarophiles have been utilized to intercept the dipolar

intermediates, i.e., isocyanates, acetylene dicarboxylate esters and

ketenes, among many others. However, apparently only one case has

been reported of a ketone performing this function and this involved

the reaction of perhaloacetones with cyanamides to form 1,3,5-oxa-
,. 45
diazines.




CH3 CF CF3 01 /CH3
1N-CEN + = 0 --- CF3 C-NH
CH CF3 N3 3


CH3 CH



3N-CN possible intermediate CF3 CC3

C/ C
CH3 C_ NCH3 + CH
SN-C=:N-C--N,
CH CH CH N 3
3 3 3



To investigate the scope of this novel interception reaction,

both the vinyl ether and the ketone solvent were varied. When isobutyl

vinyl ether was substituted for ethyl vinyl ether 3-oxa-2,2-dimethyl-

4-isobutoxy-8-phenyl-l,6,8-triazabicyclo[4.3.0]nona-7,9-dione, 50, was

formed in 47% yield. The infrared spectrum was practically identical

to that of 49 with only minor differences noted in the C-H stretching

frequencies and in the fingerprint region of the spectrum. The nmr

spectrum was similar to 49 except a doublet for the methyl groups of

the isobutyl group was present at 60.95 (6), and the multiplet due








to the methylene protons was less complex because of the isobuty]

group.




H2CH(CH3)2 OCH CH3 CHiCH
9 1 23 0 2
C CH--0 3H-
H2 CH CH CI2 C 3
Nh'N o )N-N 3
0 N =O 0= N 0 O < 00
Ph Ph
Ph

50 51 52

Changing the ketone solvent -from acetone to cyclohexanone

resulted in formation of 3-oxa-2-spirocyclohexyl-4-ethoxy-8-phenyl-

1,6,8-triazabicyclo[4.3.0]nona-7,9-dione 51 in 12% yield. Apparently

the low yield resulted from the more complicated procedure for product

isolation. The infrared spectrum appeared practically identical to

49 and 50. The nmr spectrum differed from that of 49 in that the

nonequivalent methyl resonances at 61.70 and 61.85 were replaced by

a broad multiple resonance from 61.50-62.80 (10) from the cyclohexyl

protons.

Divinyl ether, PhTD and acetone resulted in a small amount of the

tetrahydrooxadiazine 52 and a trace of 1,2-diazetidine 31b. Both were

identified by nmr with the oxadiazine spectrum resembling 49, 50 and 51,

while the 1,2-diazetidine resonances were identical to those of the

room temperature product of DVE-PhTD in methylene chloride 31b.

The mass spectral fragmentation patterns offered strong corrobora-

tive evidence for the proposed new 1,3,4-tetrahydrooxadiazine ring

structures. The fragmentation patterns were very similar to known









cyclic acetal fragmentations.6 They were different in that the

molecular ion appeared. This could be due to the unique structure

in which one ether linkage was inside the ring and the other was

outside. Schemp I shows the fragmentation pattern for 49. The

molecular ion m/e 305 (1%) is believed to fragment by two pathways,

a and b.


Scheme I

OCH2CH

b CH -0
\ C 3 a

C- .CH C / N 3 0

23 0 0 -CH3CC
N
Ph
m/e305 (M+)
SC 60
CH2
-\2
S-co \
O-- ----- 0
= -0 N 0
h Ph
el90 m/e218


4-
CH =0CH2 CH3
CH2
\2
N--N
O=< )=0 m/c247
N base peak
Ph p

-CH= CH2 /0
/ 'H
CH
c\2
-II0 N N-
0 Ph

m/e219


Pathway "a" involves loss of acetone to form m/e 247, the base

ion. This is followed by the loss of ethylene to m/e 219 (8%) which

then appears to rearrange and lose a hydrogen atom to m/e 218 (22%).

Ion m/e 190 (59%) subsequently follows by loss of carbon monoxide.

Pathway "b" involves loss of the ethoxy radical to form ion m/e 260

(7%), a general cracking course for both acetals46 and glucosides.47

Comparison of the fragmentation of 50 and 51 (Schemes II and III


m/e260


CH2

N-


m/
m/






42


Scheme II


GCR CH(CH )

CH3 H>0 C
/c H \ + 32
CH b CH2 /'-CH a
3 -- -- N ----

-0 -6CH2oCH(CH3)2 o 0- \ -C3 31
CN 3C
h
m/e333 (Mi+)

C--CE0
CH, 2 H
2 -H -CO NN


N N
bP Ph

m/el90 m/e218
base peak


CH=0CH2CH(CH3)2

CH2
\2
N-N

N
Ph
m/e275 -CHCH(CH )
2\ H 3 2
OH



\2

Ph

m/e219


Scheme III


Uc>


N-N -0CH2CH3


Ph
m/e300




CH
C2 ,H
2(--N -CO


Ph
m/el90


OCH2CH3

CH2 /J

N N -0

Ph )
m/e345 (M+)


+
CEO
C2 "H
N- -H.

0< -0

Ph
m/e218


11-DCH2 CH3
CH2
N "



Ph
m/e247
base peak
-CH- CH2

OH

CH
\2
N -N



Ph
m/e219


ci/e260









respectively) with that of 49 shows similar ions resulting from the

same double fragmentation pathway.

From these results (summarized in Table 4) it appears that the

reactivity of the 1,4-dipole is quite sensitive to stabilization of

its positive center. The high yields of oxadiazine when the carbonium

ion stabilizing substituents, ethoxy and isobutoxy, are present and

the low yield with vinyloxy are believed to mean that the intermediate

has more pronounced dipolar character when its positive center is

stabilized and hence can add across the weak dipolarophilic alkyl

ketones. This is the same reasoning used to explain the earlier

copolymerization results. In agreement with the above observations

is the PhTD-indene30 reaction in which no oxadiazine was reported even

though the reaction was performed in acetone.


TABLE 4. SUIIARY OF INTERCEPTION REACTION RESULTS


Vinyl Ether Ketone % Yield M.P.

CH2=CH-O-CH2CH3 Acetone 42% 149-151C

CH2=CH-OCH2CH3 Cyclohexanone 12%a 170-171C

CH
I 3
CH2=CH-O-CH2-C-C3 Acetone 47% 125-126'C

b
CH2=CH-0-CH=CH2 Acetone trace

(a) Yield lower possibly because of difficulty in work up.

(b) Identified from nmr. Also some 1,2-diazetidine formed.


By employing this unique property of these 1,4-dipoles, it was

felt that information on the degradation of the EVE-PhTD copolymer

could be obtained. When a high molecular weight sample of this









copolymer was refluxed in acetone, the usual decrease in molecular

weight was observed along with a trace amount of oxadiazine 49. This

was believed to result from degradation back to the initial 1,4-dipole

which in turn was trapped by the acetone. This is interpreted to mean

that, at least in part, the degradation is a reverse reaction of the

original polymer formation.

Soluble salts are generally known to exhibit significant effects

in either anionic or cationic polymerizations. It was felt that the

ions of a soluble salt would effectively "tie up" some of the "living

ends" of the propagating dipole and prevent their intermolecular cou-

pling and hence lower the molecular weight. Mhen the EVE-PhTD copoly-

merization was effected in tetrahydrofuran solution in the presence of

10 mole % of sodium tetraphenylboron, a significant change in the mol-

ecular weight was observed. A control in tetrahydrofuran yielded an

average molecular weight of. 2040 versus 940 for the sample containing

the salt.

Another mechanistic pathway which merits consideration is that of

a ring opening polymerization resulting from attack of the zwitterionic

intermediate on an unopened 1,2-diazetidine. Although the data do

not allow this mechanism to be disregarded, especially in the DVE case,

the observation of molecular weight increase with time for both the DVE

and EVE cases is not consistent with such a propagation mechanism.

This evidence is particularly persuading for the EVE-PhTD copolymeri-

zations because of two observations. The first observation resulted

from an experiment conducted in an nmr tube. This experiment showed

that when the reactants were mixed and inserted directly into the nmr

cavity only copolymer was observed. The second observation was that









even though all the PhTD was consumed after 10 minutes in the PhTD-

EVE copolymerization, the molecular weight increased over a 0.5 hour

time period (Fig. 5). Since no adduct was present as indicated by the

first experiment, the molecular weight growth is attributed to dipolar

coupling. Wilson and Beaman48 have recently observed a system in which

the molecular weight increased after an addition polymerization was

complete and attributed the phenomenon to a coupling of residual poly-

meric dipoles.

Another polymerization in which some dipolar coupling was postu-

lated was the catalytically initiated polymerization of 1,1,3,3-tetra-
49
methyl-1,3-disilacyclobutane, 53.
C11
{'3
C Si-CH3


CH3
53

The vinyl ether-PhTD copolymerizations are believed to be the

first reported cases of a dipolar coupling being the sole propagation

mechanism.



Mechanism of termination

In all of the copolymerizations the highest molecular weights ob-

tained were only in the vicinity of 3000 (Tables 1 and 2). These low

molecular weights are thought to be a result of facile termination re-

actions. As was stated earlier, ionic polymerizations are readily sub-

ject to termination reactions by impurities such as water. At least

two other termination reactions could occur. The first would be an

intramolecular dipolar coupling to a macrocyclic structure and the










second is a type of disproportionation to an inactive species as

shown below. Another possible consideration is that the dipoles are




S TN-T-N H,- N v
2 + N
0 0= 0 ---)- CHZCH 0( .O0
R N 0
Ph R





so stabilized to result in a "living" structure. Unfortunately no

experimental evidence was obtained supporting any of the possible

termination reactions.



B. Copolymerization of 4-Phenyl-l,2,4-triazoline-3,5--dione with-

Other Monomers

Vinyl acetate and divinyl carbonate

To broaden the scope of the copolymerization and reaction character-

istics of PhTD, its reactivity was investigated with several other

olefinic systems. Vinyl acetate (VAC) and Divinyl carbonate (DVC)

were chosen for investigation because these monomers were expected to

be somewhat less reactive than the vinyl ethers.

VAC was observed to react with PhTD at room temperature, but at

a considerably slower rate than the vinyl ethers. The infrared spectrum
-4
of the product exhibited a medium intensity 1610 cm.- band. The nmr

spectrum gave broach resonances at 67.48, 64.32 and 62.16. Superimposed

over these resonances were sharp singlets. A reaction conducted at

60C in a sealed tube yielded as the major product an adduct which was
assigned structure 55, (foyl hyl)-2-acty-2,4-tiazoline-3,5-
assigned structure 53, l-Cfo-a-mylmeichyl)-2-acetyl-l,2 ,4-triazoline-3,5-










TABLE 5. COPOLYMERIZATIONS AND REACTIONS OF PhTD AND OTHER MONOMERS


Comonomer



Acrylonitrile
Acrylonitrile
Acrylonitrileb

Acrylonitrile
Divinyl sulfone
Divinyl sulfone
Divinyl sulfoneb


N-vinyl carbazole
N-vinyl carbazole
Vinyl acetate
Vinyl acetate
Vinyl acetate
Vinyl acetate
Divinyl carbonate
Divinyl carbonate
Divinyl carbonate


avPO-acetone solution
b0.5 wt.%AIBN added
CCalculated from GPC


Solvent Conditions
Temp. Time


CH2C12
CH2Cl2
CH2C12




CH2C12

CH2C12

CH2C12





CH2C12
acetone
CH Cl
CH 2 Cl2


CH2C12
CH2C12
CH2C12
CH2 Cl2


--a
Yield M
n


(hr.)
42
144
24


15.1
63.0
31.8


33.0
59.3
33.5
29.0


86.0


57.3
1.2
78.3


44.9
0.36


21


60 24 73.5


Product


-- PhTD oligomeric species
-- PhTD oligomeric species
-- Possibly some copolymer
from elemental analysis


PhTD oligomeric species
PhTD oligomeric species
No sulfur present from
elemental analysis
,000c 1:1 copolymer
-- 1:1 copolymer
-- Copolymer and 55
-- Not identified

370 Mostly 55
-- Mostly 55
-- 2:1 copolymer
Not identified

1240 2:1 copolymer









done. This compound apparently arose from an internal trap of the

intermediate 1,4-dipole 54.




+ 0
CIE 0 0 C-H

C 2 / CH3 -C C-CH
N-N N-N
0:= ( 0 0M =0

Ph Ph

54 55

The infrared spectrum of 55 showed two weak bands characteristic

of an aldehyde carbon hydrogen stretch at 2860 cm.-1 and 2750 cm.-1 A

double carbonyl absorbance at 1800 cm.- and 1730 cm.- was also char-

acteristic of the urazole type structure. The nmr spectrum (Fig. 7)

gave resonance signals at 69.56 (singlet, aldehyde hydrogen, 1), 67.50

(singlet, aromatic hydrogens, 5), 64.80 (singlet, methylene hydrogens,

2) and 62.60 (singlet, methyl hydrogens, 3). The mass spectrum yielded

the correct parent peak at m/e 261 and the elemental analysis agreed

with the 1:1 structure.
-l
The broad nmr resonances and the 1610 cm.- infrared band were

probably indicative of the formation of some copolymer in the room

temperature reaction. The small amount of polymeric material is be-

lieved to be indicative of the low activation energy of the intramolec-

ular six menbered transition state rearrangement.

An attempt to trap the initial dipole before the intramolecular

reaction occurred was made utilizing a large excess of phenyl isocy-

anate as the dipolarophile. Only 55 was isolated. The reaction was

also performed in acetone so that the initial dipole could be trapped


































~i --------------------- i --- ---i-- ------


9.0 8.0 7.0 6.0 5.0 4.0 3.0
PPe sec
Figure 7. Nmr spectrum of 1-(formylmethyl)-2-acetyl- ,2,4-triazoline-3,5-dione.









to form an oxadiazine as was accomplished in the vinyl ethers. The ma-

jority of the reaction was 55. A few milligrams of material were iso-

lated which gave an nmr spectrum with resonance signals at 66.30 (mul-

tiplet), 63.75 doublett) and 61.72 (singlet). The spectrum was

complicated by the presence of 55. The above resonances appeared in

the ratio of 1:2:6. This could be evidence for the formation of a

small amount of the oxadiazine 56.


0-CCH3
CH--0

\2 /CH3
N--N


Ph

56

DVC was found to react slowly at room temperature and at 60C to

give a material shown by elemental analysis to be a 2:1 structure. A

strong 1610 cm.-1 band was observed in the infrared spectrum and the

nmr spectrum gave broad resonances at 67.38 (singlet, broad, 6) and

65.31-63.31 multiplee, broad, 1). A molecular weight of 1220 was ob-

tained for the 6000 polymerization. No observations were indicative

of the occurrence of a double internal trapping reaction analogous to

the vinyl acetate reaction.



Divinyl sulfone and acrylonitrile

The normally electron poor olefins divinyl sulfone (DVS02) and

acrylonitrile CAN) were chosen for investigation to see if they would

act as electron donors with PhTD.

DVS02 appeared to give some reaction since more solid was obtained









in an attempted copolymerization at 600C than was obtained with a con-

trol of PhTD. No sulfone absorbances were noted in the infrared spec-

trum and an elemental analysis only yielded a trace of sulfur.

AN showed no indication of reaction at room temperature or at

600C for six days. At 60C, with a free radical initiator present,

some product appeared to result. An analysis of the infrared spectrum
-l
showed a new medium intensity 1610 cm.- band. An elemental analysis

yielded a higher nitrogen content than would result from a reaction

only involving PhTD. No structure assignments were feasible.



N-vinyl carbazole

N-vinyl carbazole CNVC) was observed to spontaneously copolymerize

at 25C to yield an 86% yield of a 1:1 copolymer. The composition was

established by elemental analysis. Only a weak-medium 1610 cm.-I ab-

sorbance was observed in the infrared spectrum. The nmr spectrum yield-

ed two large broad resonances centered at 68.50 and 65.80. Because of

the weak 1610 cm.-1 absorbance the polymer structure was thought to

be 57.






N-N---- CH --CH


N
h -n



Insolubility of the polymer in acetone precluded the usual vapor

pressure osmometer molecular weight determination. However, calculation

of the number average molecular weight from gel permeation chromatog-










raphy, calibrated with polystyrene, gave a value of 21,000. The

weight average was calculated to be 54,000 and the molecular weight

distribution (M /M ) was 2.57. In making the calculations a very
w n
dangerous assumption was necessary. It was assumed that polystyrene

and the copolymer had similar coil dimensions in the solvent used

for the determination. Although this assumption appeared to be valid

in the DVE-PhTD copolymer, it was not necessarily valid in this case.

The molecular weight obtained in this system is significantly higher

than in the vinyl ether copolymers. No reasons are apparent for the

change in structure and the change in molecular weight of the NVC

system.

When the polymerization was conducted in acetone, a similar

polymeric structure was obtained. Only a minute amount, if any, of

the corresponding oxadiazine was observed. An nmr spectrum from

a small amount of apparently non-polymeric material showed multiplets

at 64.50 from methylene hydrogens and 62.20 from methyl hydrogens.

Not enough material was isolated to identify and characterize this

product. The failure of acetone to trap the probable intermediate

dipole is probably due to the large steric effect of the vinyl

carbazole moiety.

Stille and Aoki 50 have initiated the homopolymerization of

electron donors by addition of catalytic amounts of strong electron

acceptors. The homopolymerizations are proposed to be initiated by

an excited ionic s'ate of a charge transfer complex. Since NVC is

known to readily homopolymerizc, it was thought that the addition of

a small amount of PhTD to a solution of NVC could possibly trigger a

cationic homopolymerization of the NVC in which the initiation would










be effected by the positive end of the dipole. An attempted polymer-

ization was unsuccessful.



C. Reactions and Attempted Homopolymerizations of 4-Phenyl-1,2,4-

triazoline-3,5-dione

4-substituted-l,2,4-triazoline-3,5-diones have the potential to

yield polymers possessing a nitrogen backbone if an initiation could

be effected through the nitrogen to nitrogen double bond. This promise

made the investigation of the behavior of the triazoline diones in

the presence of radical and ionic initiating species an attractive

proposal.

PhTD has been described51 as decomposing instantly in basic

solution, while in the presence of acid, water or alcohol the rate

of decomposition was noted to be slower. Even in the presence of

light or in solution at room temperature some decomposition was

reported. No one has studied the decomposition products and their

mechanisms of formation.

The thermal decomposition of PhTD at 60OC in a scaled tube was

studied to determine if there was any appreciable decomposition that

could compete with the copolynerizations. During the course of the

reaction the color remained red and a few milligrams of a white

crystalline solid formed in the bottom of the tube. Precipitation

of the red solution yielded a small amount of tan-w:hite solid 59.

The white cry-talline solid did not melt when the temperature

was raised to 300"C. The infrared spectrum gave no saturated carbon-
-I
hydrogen stretching absorbances and gave a double carbonyl at 1785 cm.

and 1755 cm.-1 The mass spectrum yielded a parent peak at m/e 322
and 1755 cm. The mass spectrum yielded a parent peak at ale 322










and a base peak at m/e 119 (phenyl isocyanate ion). Structure 58,

3,7-diphenyl-1,5-diazabicyclo[3.3.0]octa-2,4,6,8-tetraone, was assigned

from this data. An elemental analysis perfectly agreed with the

calculated value.

0 0


Ph-N N-Ph


0 0

58

Two reports of 58 were found in the literature. Snyder52 reported

the formation of a bright orange solid, melting point 203-2040C,

during a refluxing reaction of PhTD. In this case PhTD was generated

by oxidation with t-butyl hypochlorite in acetone. The only structure

proof presented was infrared data which included a double carbonyl
53
and an aromatic absorbance. Koch and Fahr reported the formation

of 58 in a thermal reaction of PhTD in an apolar solvent. No structure

proof or physical characteristics were presented.

The tan-white solid 59 isolated by precipitation into hexane

had 3500 cm.-1 and 1715 cm.-1 absorbances in the infrared spectrum.

The nmr spectrum gave broad resonances at 67.50 (broad multiple, 6)

and 64.48 (broad multiple, 1). The number average molecular weight

from vapor pressure osmometry was found to be 600. The elemental

analysis did not correspond to any regular structure resulting from

a homopolymerization of PhTD.

When PhTD was heated in a sealed tube in methylene chloride

solution in the presence. of azobisisobutyronitrile, results identical

to reaction without the free radical initiator were obtained. An










attempt to initiate a free radical homopolymerization of PhTD by

photolysis of benzoyl peroxide at -45C only resulted in a small

amount of the oligomeric PhTD decomposition product 59.

In attempting to explain the mechanistic pathway for the thermal

decompositiolof PhTD to 59, the first reaction is probably the forma-

tion of phenyl isocyanate. Phenyl isocyanate could then in turn


heat

0 0 Ph-N C= 0
-N
N 2
Ph -CO


react with water to form aniline. When a catalytic amount of aniline

H 0 -CO
Ph-N=C=0 + H20 -> [Ph-N-c-0-H] -- PhNH2


was added to a methylene chloride solution of PhTD, some of the

oligomeric decomposition product 59 resulted.

Another related experiment was to see what products were formed

in the decomposition of PhTD by water, since PhTD had already been

shown to readily decompose in water.5 When PhTD, in dioxane solution,

was added to water a vigorous reaction insued and a large amount of

oligoneric product 59 was obtained. A small amount of N,N'-diphenyl

urea was also obtained. One of the products from the reaction is

most assuredly phenyl isocyanate which then goes to aniline and then

reacts with more phenyl isocyanate to yield the diphenyl urea.

Since aniline served as a catalyst for for:ration of the oligomeric

product 59, an investigation using other nucleophilic species was

initiated in hopes of effecting the formation of high polymer.

Triethylamine was used as the initiator and a similar product 59









was obtained. Surprisingly approximately 10% of 58 was

isolated.

The strong nucleophilic reagent, sodium cyanide in dimethylforma-

mide was then used as the initiator and a large yield 70-80 per cent

of the tetraone 58 was obtained. A small amount of 59 was also obtained.

The rationalization of the formation of 58 from attack of a

nucleophile on PhTD presents an interesting mechanistic problem that

was not covered in the scope of this research. However, the following

explanation is put forth as a possible mechanistic pathway of the

unusual reaction.
54
Kealy54 has observed the formation of 61 from the decomposition

of diazoquinone 60. He did not propose a mechanism for the formation

of 61, but only referred to earlier work on the decomposition of azo

compounds by radical pathways. For example, Leffler and Bond5 have

studied the radical decomposition of dibenzoyl diimide 62 where 63 is

one radical intermediate.
0 0
PhC-N=N-CPh 62
0 0 0


IN 0
t 2 PhC.
0 0 0
63

60 61

For the diazoquinone, a probable diradical intermediate would

be 64 which could couple with an intact molecule of diazoquinone 60

to yield 61.

If such a diradical. intermediate 65 was involved in the formation

of the tetraone 58 from a nucleophilic catalyzed reaction of PhTD









0



0'
0


+ 60


64

an unusual carbenoid mechanism could be involved as shown below. No

proof has been gathered in support of this mechanism, although in the

studies conducted on the radical decomposition of 6255 much higher

rates of decomposition were observed in strongly nucleophilic solvents

like aniline. The reason for this could be a nucleophilic catalyzed

reaction as was discussed for the formation of 58.


TABLE 6. SUMMARY OF CATALYZED PhTD

Conditions


90C, vacuum

Most electron poor comonomers

CH2Cl2, 600C, 70 hrs., sealed tube

CH2C12, 60C, 24 hrs., sealed tube

water, dioxane, 25'C, 1 hr.


aniline, CH2C12, 25C

triethyl amine, CH2C12, 25'C, 1 hr.

sodium cyanide, dimethylformamide
2.5 hrs., 25"C


REACTIONS

Products


(n = 1000)

(small amounts)

(27%), 58 (1%)

(10.4%), 58 (trace)

(61.5%, diphenyl
urea, (7.8%)

(22.0%) (Mn = 470)

(24.5%), 58 (9.5%)

(small amount)
(approximately 80.0%)


A summary of all the reactions and decompositions of PhTD is

presented in Table 6.

While this research was being conducted, Stickler and Pirkle12

reported the first synthesis of a nitrogen backboned polymer. Their


Exp.
No.










o=< )o +- -o J \ -

N I N N + N N
N N +NI
Ph Ph Ph







Ph


65



success resulted from a visible light irradiation of 4-n-butyl-l,2,4-

triazoline-3,5-dione.



D. Diels Alder Polymers

Synthesis of 4,4'-(4,4'-diphenylmethylene)-bis-l,2,4-triazoline-3,5-

dione

Since the diisocyanate 66, 4,4'-diphenylmethane diisocyanate,was

readily available from commercial sources, the bis triazoline dione

selected as a target for synthesis was 69, 4,4'-(4,4'-diphenylmethyleno)-

bis-1,2,4-triazoline-3,5-dione. The synthesis of the diurethane

precursor 67 was accomplished in a near quantitative yield by the

addition of two moles of ethyl carbazate to 66. The infrared .spectrum

yielded strong N-H stretches at 3380 cm. and 3305 cm.-. Strong

carbonyl absorbances vere observed at 1735 cm.- and 1685 cm.- The

nmr spectrum gave resonances at 68.77 (singlet, hydrogens on nitrogen,

2), 67.91 (singlet, hydrogens on nitrogen, 2), 67.20 (A2B2 quartet,

aromatic hydrogens, 8), 64.05 (quartet, methylene hydrogens, 4),









63.79 (singlet, methylene hydrogens, 2) and 61.19 (triplet, methyl hy-

drogens, 6.). The product gave the correct elemental analysis.




CH -N=C-0 24- 2H2NNHCOCH2CH3- CHH0 --NHCNHNHCOCII2CH3


66 67

67 was quantitatively cyclized to the bis urazole 68 with 4M po-

tassium hydroxide. The infrared spectrum yielded a broad band front



67 4M1 KOH CH2 H
11 H 1 2
68 0
-1 -i
3320 cm. to 2760 cm., a characteristic noted in the simple urazoles,

and gave a double carbonyl absorbance at 1765 cm.- and 1680 cm.- The

nmr spectrum gave resonance signals at 67.80-67.20 (broad with a sharp

spike at 67.38, aromatic hydrogens and hydrogens on nitrogen, 12) and

64.03 (singlet, methylene hydrogens, 2). The elemental analysis

agreed with the calculated value.

The oxidation of 68 to the bis triazoline dione 69 was accomplished

in approximately 80% yield using dinitrogen tetroxide in the same man-

ner as employed by Stickler and Pirklel2 in the synthesis o[ the simple

triazoline diones. The infrared spectrum showed an absence of any N-H

stretching frequencies and yielded the characteristic double carbonyl

at 1790 cm.-1 and 1760 cm.-1 The nmr spectrum yielded, surprisingly,

only two singlets, on, at 67.48 (aromatic hydrogens, 8) and 64.18

(methylene hydrogens, 2).

69 reacted readily -with reactive dienes. The reaction with 2,3-

dimethyi-l,3-butadiene yielded 70. 70 was identified by its nmr spec-











II 1 0 Ci
7 CH CH 3
C2 NC i 3 -3 CH-2 N
2 0 0 3
69 70

trum which showed resonance signals at 67.33 multiplee, broad, aromatic

hydrogens, 8), 64.00 (broad singlet, allylic next to nitrogen and benzy-

lic hydrogens, 10) and 61.75 (broad singlet, methyl allylic hydrogens,

12).



Diels Alder polymerization of styrene and 69

Cookson and coworkers51 have investigated the Diels Alder reactions

of triazoline diones and found that PhTD spontaneously reacted with

styrene to yield the double Diels Alder adduct 71. Maleic anhydride56

and ethyl azobisformate57 have been shown to react with styrene in a

Diels Alder fashion, but the final products in both cases were 72 and

73. These products resulted from an ene reaction after the first Diels

Alder reaction. Cookson's results meant that styrene, potentially,

would be an attractive bis diene to investigate with 69.

When styrene was reacted with 69 at room temperature in dimethyl-

formamnrde solution, the deep red initial color faded to a much lighter

red after two hours. After seven and one half hours, the red color,

characteristic of unreacted 69, persisted. The solution was divided

and the first half was precipitated into ether to yield a tannish,

highly electrostatic powder. The second half was in turn divided into

two portions and a discharge of the red color was noted after a few

minutes. Precipitation into ether yielded an identical polymer (in-













SH H-N-CO2CH2CH3
O22
H H -C02CH2CH3

0 N-CO2CHCHH
-0
0 dO2 CH2H3
0-
72 73
0
PhNN I I



Ph-N -I
S -0 ,
NN & N
71 0 0 75 0/ NPh









frared) as the portion precipitated while still red. The last portion

was heated to reflux and immediately it began to darken. It was pre-

cipitated into ether and a much darker solid resulted.

The repeat structure of the polymer was assigned to 74, which re-

sults from a Dicls Alder adduct which rearomatizes via an ene reaction

as 72 and 73. This is contrary to what was expected a priori. The

assignment was made from the infrared and nmr data and comparison to

the model compound 75.

When PhTD and styrene were reacted in methylene chloride at room

temperature 75 was formed rather than the reported Diels Alder adduct
-i
71. The infrared spectrum gave an N-H stretch at 3280 cm. and the

usual double carbonyls at 1765 cm. and 1720 cm. The nmr spectrum

(Fig. 8) gave resonance signals at 68.38 doublett, hydrogen on nitrogen,

1), 67.35 and 67.38 doublett and multiple respectively, aromatic

hydrogens, 4), 65.70 (triplet, benzyl hydrogen, adjacent to nitrogen,

1), and 64.22 multiplee, methylene hydrogens, 2). The elemental

analysis agreed with the 2:1 structure.

The polymer gave the double carbonyl in the infrared spectrum at

1780 cm. and 1715 cm.-. The N-H stretch was very weak. The nmr

spectrum (Fig. 9) showed resonances at 68.40 doublett, broad, hydrogen

on nitrogen, 1), 67.37 (singlet, broad, aromatic hydrogens, 12), 65.67

(singlet, broad, benzyl hydrogens adjacent to heteroatom, 1) and

64.50-63.80 (muitiplet, broad, two sets of methylene hydrogens, 4).

The polymer wis soluble in both dimethylformamide and dimethyl-

sulfoxide. The thermal decomposition was recorded using a Differential

Scanning Calorimeter and.was found to start at 3070C. An intrinsic

viscosity determined in direthylformamide at 280C was 0.12. Calculation




































I I I 1
8.0 7.0 6.0 5.0 4.0 3.0 2.0

PPM (6)
Figure 8. Nmr spectrum of the Diels Alder, ehe adduct of 4-phenyl-1,2,4-triazoline-3,5-dione and styrene.








































I I I I I I 1
9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0
PPM f s a

Figure 9. Nmr spectrum of the Diels Alder, ene polymer from styrene and bis triazoline diane.









from gel permeation chromatography showed a molecular weight distri-

bution of 3.34 with the weight average molecular weight, An = 36,000.

These values were calculated from a calibration with a polystyrene

standard, and again the assumption is made that the coil sizes are

similar for the two polymers.

An attempted polymerization of 69 using sodium cyanide in

dimethylformamide yielded a light brown polymeric material. The

synthesis of a polymer with structure 76 was the object of this exper-

iment. The infrared spectrum of this material was not similar to

the monomeric tetraone 58 so apparently the desired decomposition and

coupling reaction did not take place.















CHAPTER III

Triple Strand Polymer Model Compound Studies

A. Attempted Synthesis of Tetracyclo [4.4.0.1 '9.1 48] Dodecane and

Related Systems

Synthetic schemes

The synthetic pathway for the attempted synthesis of the cage

structure 18 is shown below in Scheme IV.

SCHEME IV


0
SI


o8
0
89


CH20R OH20R (1) ORCH O21s

JCH OR Y CHOR (2) C- COAs
2 0 -- Q2 2
77a,b 83a,b 24

R=a= -OCCH3
R=b= -H (1) catalytic hydrogenation
(2) MsCI


24 base


reduction 18


Scheme V is a proposed synthetic pathway to 25 which is the precur-

sor to 26, a simplified cage structure re-lated to 18.









SCHEME V
IC CHOR 0 0
< >2 O CH2OR (1) H O20Ms
+-2 (2) K

79a,b 0
89 0 8a,
R=a= -OCH3 25
R=- (1) catalytic hydrogenation
R=b= -H
(2) MsCI

base reduction
25 -- -------->- 26


Synthesis of dienes

The first step in Scheme IV required either 2,3-di(acetoxymethyl)-

1,3-butadiene or 2,3-di-(hydroxymethyl)-1,3-butadiene, 77a and 77b.

Both of these dienes had previously been synthesized by Bailey and

Sorenson.58 These authors prepared 77a by pyrolysis of 2,3-di-(acetoxy-

methyl)-l,4-diacetoxybutane, 81, at 480C. Although the reported


CH CH Br CH OCCH
NB0LS /- S2 A' / >'2 77a3
2 C\ fCHJ\ r CHCH2lC 0.1 mm.
CH!3 2 2 3
82 83 84



yield was 84%, this was based on the recovery of unreacted starting

material and the formation of a mono elimination product. Actually

the conversion to 77a was only 16%. It was felt that the method of
29
Butler and Ottenbrite29 used in the preparation of 2,3-di-(bromo-

methyl)-l,3-butadione would result in a more efficient preparation

of 77a.

The first precursor to the desired dines, 2,5-dihydro-3,4-

dimethylthiophene-l,l-dioxide or commonly referred to as dimethyl-










0 0
(CH3COCH2) 2CHC CH2OCCH3) 2
81
CH3 / I Br //- CHCHOCCH3
02S I NBS 02S As ICH3 -O- 02S- 79a
CH3CN
85 86 87


butadiene sulfone, 82, was prepared by the method of Frank and Seven59
29
in 90% yield. This was then brominated2 with N-bronosuccinimide in

38% yield to 83. Treatment of this dibromide with silver acetate in

acetonitrile resulted in a 73% yield (after recrystallization) of the

diacetoxy sulfone 84. The elemental analysis of this compound agreed

with the calculated and the infrared spectrum showed a strong carbonyl
-l
absorbance at 1720 cm.- for the ester group. The nmr spectrum yielded

resonances consistent with the structure and they appeared at 64.75

(singlet, broadened, allylic hydrogens adjacent to acetoxy, 4), 63.86

(singlet, broadened, allylic hydrogens adjacent to sulfone, 4), and

62.08 (singlet, methyl protons, 6).

Pyrolysis of 84 was accomplished smoothly at 200"C and 0.1 mm

pressure in 56.6% yield using a Hoskins furnace as the external heat

supply. The white solid diene was purified by recrystallization and

yielded the reported melting point.58 Saponification5 to 77b was

accomplished in 90% yield.

By using the same general procedure as used in the preparation of

84, the sulfone precursor, 87, to the acetoxymethyl diene 79a was

prepared in 74% yield. The bronmcmethyl sulfone 86 was prepared by

the method of Krug and Yen60 by bromination of isoprene sulfone 85

with N-bromosuccinimide. When 86 was reacted with silver acetate in








-l
acetonitrile 87 was formed as a yellow-brown oil.. It showed a 1735 cm.

ester carbonyl in the infrared spectrum and yielded the correct elemen-

tal analysis. The nmr spectrum exhibited resonance signals at 66.07

(singlet, broad, vinylic hydrogen, 1), 64.69 (singlet, broad, allylic

hydrogen next to acetoxy, 2), 63.81 (singlet, broad, allylic hydrogen

next to sulfone, 4) and 62.10 (singlet, methyl hydrogens, 3).

Pyrolysis of this oil was accomplished at 2000C at 0.5 mm. and an

84% yield of 79a was obtained. This was purified by distillation and

the infrared characteristics were identical to those reported by

Bailey and coworkers6 who had prepared 79a from the pyrolysis of 88.


9 0
CH COACH CH CHCH o0CH
CH 2 CCH3
0

88



Attempted Diels Alder reactions with p-benzoquinone

When the diacetoxymethyl diene 77a and the dihydroxymethyl diene

77b were reacted with p-benzoquinone, 89, the normal Diels Alder adducts

were not isolated. Reaction of 77a with 89 in acetic anhydride resulted

in the formation of the dehydrogenated adduct 90. The infrared spectrum
-i
of this reddish brown solid exhibited carbonyl absorbances at 1725 cm.-
-i
(ester) and 1655 cm.- (quinone). The nmr spectrum yielded resonances

at 66.75 (singlet, quinodial hydrogens, 2), 64.78 (singlet, allylic hy-

drogens adjacent to acetoxy, 4), 63.23 (singlet, doubly allylic hydro-

gens, 4) and 62.12 (singlet, methyl hydrogens, 6). A correct elemental

analysis was obtained. The same reaction carried out in benzene

yielded a crude oil possessing the same nmr resonances as 90 with








additional resonances at 66.77, 66.75, 64.64 and .62.43. The 63.23

resonance was broadened considerably. This was apparently a mixture of

unreacted quinone (66.77), 90 and the desired Diels Alder adduct 78a.

On addition of ethanol to the oil 90 was formed as a precipitate and no

indication of 78a was found in a spectroscopic analysis.

The reaction of 77a and 89 was then performed in refluxing chloro-

form and the progress of the reaction was followed by nmr spectroscopy.

Disappearance of resonances attributable to starting quinone and diene

was observed and the appearance of signals at 66.68 (singlet, quinodial

hydrogens, 2), 64.65 (singlet, allylic hydrogens adjacent to acetoxy,

4), 63.27 multiplee, broad, bridgehead hydrogens, 2) and 62.44 (multi-

plet, broad, allylic hydrogen, 4) was noted. After 135 hours a con-

version of 80% was calculated from the nmr spectrum. Removal of the

chloroform yielded a yellow oil. This was chromatographed on silica
-l
gel and a white solid resulted that showed a strong 3400 cm.- band
--l .
and a disappearance of the 1650 cm.- in the infrared spectrum. This

indicated that 78a had rearranged to the hydroquinone derivative 91.

The nmr spectrum gave resonances at 66.64 (singlet, aromatic hydrogens,

2), 64.48 (singlet, allylic hydrogens adjacent to acetoxy, 4), 63.47

(singlet, doubly allylic hydrogens, 4) and 62.88 (broad, hydroxyl

hydrogens). 0
I! CIt2R
CH2R

0 CHR CH2R


6 12 IR CE 2 R 90
2 CH 2 CUR
89 77a 0
R= -0CCl3 C 9 CH2R
U 91
H









The reaction of the dihydroxy diene 77b with 89 failed to pro-

duce the desired Diels Alder adduct as an isolable material also. In

refluxing chloroform a brownish solid formed whose nmr spectrum gave no

resonances that could be assigned to a Diels Alder adduct.

When the reaction was performed in tetrahydrofuran, a brownish-

yellow oil was obtained which was initially chloroform soluble, but

precipitated within a short time as a white solid. The absence of a

quinone carbonyl in the infrared spectrum and the absence of bridge-

head hydrogen resonances in the nmr spectrum was indicative that the

desired Diels Alder adduct 77b was not present. The presence of a

strong 1710 cm. absorbance in the infrared spectrum quite possibly may

be due to some double Diels Alder adduct 92. There was, however, no







HOH2C CH20H
0 0
11OH9 C .!y< CH OH CH OH


2 H 2 O 2

92 H 93


other indication of this. More likely, since the bridgehead protons did

not appear in the nmr spectrum, 93 was formed.

The Diels Alder adducts of 89 and both 2-bromomethyl-1,3-butadiene,

94, and 79a were not isolable under the reaction conditions employed.
60
94, the bromine substituted diene, reacted with 89 in acetic

anhydride to give a 60% yield of the aromatized and acetylated product

95. All spectral characteristics were consistent with the structure

OCOCH
CH Br I 3 CH2Br
89 2 acetic
89 anhydride
4 1 95
94 OCOCH3








-l
proposed. The infrared spectrum gave a strong 1750 cm. carbonyl from

the ester functions. The nmr spectrum had resonances at 67.00 (singlet,

aromatic hydrogens, 2), 66.05 multiplee, vinylic hydrogen, 1), 64.08

(singlet, broad, allylic hydrogens adjacent to bromine, 2), 63.30 (sing-

let, broad, allylic hydrogens, 4) and centered at 62.30 (two singlets,

nonequivalent methyl groups, 3 each). The mass spectrum gave the molec-

ular ion and the molecular ion +2 in the correct percentage for one

bromine atom, m/e 339 and m/e 341. The base peak m/e 176 corresponded

to the loss of both acetoxy groups and the bromine atom.

In the reaction of the acetoxymethyl diene, 79a, with 89 in benzene

at room temperature, quinhydrone,62 the molecular complex of hydroquinone

and quinone, was formed as an insoluble precipitate. It was identified

by its melting point, nmr spectrum and mixed melting point with an

authentic sample. On evaporation of the benzene a dack oil was formed,

which on extraction with hot petroleum ether gave a bright yellow solid

which quickly darkened. Column chromatography on silica gel resulted

in a yellow oil which quickly darkened also. A thin layer chromatogram
-l
yielded two spots. The infrared spectrum gave a strong 3500 cm.1

absorbance indicative of a hydroxyl group. The nmr spectrum was very

complex and from the methyl signal at 62.10, three spikes were apparent

indicating a mixture of three compounds. The bridgehead protons for

the Diels Alder adduct appeared to be present as a multiple at 63.25.

The downfield region centered at 66.80 appeared as a double. From

these data it is believed that the initially formed Diels Alder adduct

80a aromatized to 96. From the color and the apparently three differ-

ent methyl groups, some dehydrogenated material 97 was possibly present

also. All attempts to separate the mixture were unsuccessful. When









the reaction was carried out in ethanol a similar oily solid was

obtained that yielded an infrared spectrum identical to the previous

reaction in benzene.

H
60 0
CH2CH OC C0&
11- 2 3 2 3 C CN

IO II 0C CN
0 0 CH CN
H 96 97 3 98


The acetoxydiene 79a readily reacted with tetracyanoethylene to

yield the Diels Alder adduct 98. Spectroscopic data and the elemental

analysis were all consistent with the normal Diels Alder structure.

At the present time, there appears to be no plausible explanation

why the Diels Alder adducts of p-benzoquinone, 89, and the dienes 77a,

77b, 79a and 94 isomerize so facilely to the hydroquinone derivatives

or dehydrogenate to the quinone like structures. Since quinhydrone

appeared as a byproduct in the formation of 90 and 96, 89 probably ahts

as an oxidizing agent in the reactions.

Although these reactions appear to be the first time such reactions

have been observed to occur spontaneously, Ansell and Knights6 have

reported the facile aromatizations of some Diels Alder adducts of

1,1'-acetoxyvinylcyclohexene, 99, and 89. They found that in ethanol-

0
R= -0CCH3 0
0 0 0



99+ 8 --100. 101 102

99 100 101 102










at room temperature the normal Diels Alder adduct 100, formed in 63%

yield. In refluxing methanol, however, the authors observed the form-

ation of 101 and 102. They offered no reasons for their observations

but did report that most aromatizations of this nature are catalyzed

by acid or by base. A previous synthesis of 10064 revealed that melt-

ing the adduct and then resolidifying resulted in the formation of 101.



2-Cyclohexene-l-one and diazoguinone as dienophiles

As an alternative approach to the synthesis of a precursor

capable of undergoing the cyclization reaction to the cage structures,

it was decided to employ dienophiles whose adducts were incapable of

undergoing the facile aromatization reaction. The two dienophiles

selected for this study were 2-cyclohexene-l-one 103 and diazoquinone

104.

0 0
NI I




0

103 104


If the normal Diels Alder adduct, 105, of 103 and 79a were to

form then it would not be capable of aromatizing. Hence it was believed

that the reactions shown in Scheme VI could be followed.

The synthesis of 103 was accomplished by bromination of cyclo-

hexanone with N-bromosuccinimide65'66 followed Ly dehydrobromination

with colliding. The bromination reaction was accomplished in a

53% yield, while the dehydrohalogenation gave a 58% yield of the

desired a,3-unsaturated ketone, an improvement over the 42% yield









SCHEME VI

0 0
OCCH20CCH^ -1
103 + 79a IH2 OCH3 1) catalytic
hydrogenation

separate 2) Ms Cl



CH OCCH
0
105
10


j Y -CH20Ms base as


106


reported by the original investigators.67 An attempted dehydrobromin-

ation using lithium bromide in dimothylformamide68 resulted in a

yellow viscous oil.
69
From earlier experiments with 103 by Bartlett and Woods, this

dienophile was known to be quite sluggish in the Diels Alder reaction;

therefore forcing reaction conditions were employed.

An autoclave attempt to form the adduct from neat reactants at

2000C resulted in a waxy, gummy, polymeric substance. This material
-1
gave a sharp carbonyl absorbance at 1710 cm.- The nmr spectrum

yielded broad resonances centered at 67.00 (1) and 61.00 (13).

In benzene solution, in a sealed tube at room temperature for

four days,starting materials were recovered. 103 and 79a were then

reacted neat, in the presence of a small amount of hydroquinone, in

a sealed tube at 190C for three days. As in the autoclave reaction,

a polymeric substance was isolated. It had the identical spectral

characteristics of the former polymer.









Aluminum chloride had been found to be'an effective catalyst
70
for sluggish Diels Alder reactions. When the Diels Alder reaction

of 103 and 79a was attempted in the presence of a catalytic amount

of anhydrous aluminum chloride, a vigorous exothermic reaction was

noted and could only be controlled by use of an ice bath. On work up,

an oil was obtained that yielded a double carbonyl absorbance at

1680 cm.- and 1710 cm.- Chromatography on silica gel resulted in
-i -
an oil with a strong 1705 cm.- absorbance and no 1680 cm.-1 absorbance.

The nmr spectrum exhibited resonances consistent with structure 107

with 65.85 multiplee, vinyl hydrogen, 1), 64.05 (singlet, allylic

hydrogens next to chlorine, 2) and 62.20 (multiplet, broad, ring

hydrogens, 12). No resonances that could be assigned to the acetoxy

methyl hydrogens were present.

The mass spectrum gave a parent peak at m/e 198 with a P+2 peak at

m/e 200 which was 35% of the parent. The theoretical P+2 intensity71

for one chlorine atom is 32.6%. The base peak of the spectrum was

m/e 163 corresponding to loss of the allylic chlorine atom.


0
CII2Cl





107


The mechanism is not known for the formation of 107 but one

could speculate that the initial Diels Alder adduct, which appears to

be present in small yield from the infrared spectrum, reacts with

adventitious hydrogen chloride present. It is generally known that a

trace amount of this impurity is contained in aluminum chloride.









The use of diazoquinone, 104, as a dienophile was believed to

be an attractive course of action to pursue to obtain an adduct incapable

of aromatizing. Scheme VII shows the intended reaction sequence.

Kealy54 had reported the synthesis of 104 and had reported it to be

an extremely potent dienophile.

SCHEME VII

SI0 OR 1) catalytic
S / CH 20R hydrogenation
+ 77a,b _
,N CIH 2R 2) MsC1
00 0
108a,b

CH20Ms 0



0
109

0

The synthesis of 104 was accomplished by oxidation of the potassium

salt of maleic acid hydrazide with tert-butyl-hypochlorite at -77C

in acetone. Reaction of 104 with the diacetoxydiene 77a at -55C for

twelve hours yielded 45% of a light yellow crystalline solid which

was consistent with structure 108a in every respect. The infrared
-i
spectrum gave the ester carbonyl at 1730 cm.- and the quinone amide

carbonyl at 1650 cm.-I The nmr spectrum gave resonances at 66.92

(singlet, vinyl hydrogens, 2), 64.80 (singlet, allylic hydrogens

adjacent to nitrogen, 4), 64.57 (singlet, allylic hydrogen adjacent

to acetoxy, 4) and 62.09 (singlet, methyl hydrogens, 6). The elemental

analysis agreed with the calculated value.

The reaction of 104 with the dihydroxy diene 77b yielded the









Diels Alder adduct 108b. Again all spectral characteristics were

consistent with the assigned structure. The infrared spectrum gave

absorbances for the hydroxyl groups at 3480 cm.- and 3400 cm.- The

amide like carbonyl appeared at 1630 cm.-1 The nmr spectrum had

resonances at 66.98 (singlet, vinylic hydrogens, 2), 64.51 (singlet,

allylic hydrogens adjacent to hydroxyl, 4), 64.11 (singlet, allylic

hydrogens adjacent to nitrogen, 4) and 63.50 (broad, probably hydroxyl

hydrogens, no integration). The elemental analysis agreed with the

calculated values.



Attempted catalytic hydrogenation of Diels Alder adducts

The catalytic hydrogenations of the adducts 108a and 108b to the

desired structure for the cyclizations were unsuccessful. Two catalyst

systems were employed and both were chosen for their efficient reduction

of double bonds and their inactivity toward hydrogenolysis of reactive

substituent groups.

The catalyst system, 5% rhodium on carbon, has been successfully

used in the reduction of compound 110 to 111.72 Hydrogenation using

5% palladium on carbon has been found to be efficient in systems

0
II
SRhN/C
[ 1-- ~ \\ >-


0--- =o0 - -'C=o

110 111


containing allylic acetoxy groups. Compound 112 was reduced to 113

using this system.73









0
0 OCH 1.
S3 0 CCH3





0 II
0

112 113


The results of the hydrogenation attempts are shown in Table 7.

In all cases, a mixture of products appeared to be present from the

complex nmr spectra. Attempts at separation by column chromatography

were almost unanimously unsuccessful.

Two distinct trends, however, were apparent from these experiments.

The first was that the quinone like double bond was easily hydrogenated

and the tetrasubstituted double bond was highly resistant to reduction.

In all atmospheric hydrogenations almost always approximately one-half

of the theoretical hydrogen uptake was recorded in the first fifteen

minutes. In experiment 3, the hydrogenation of 108b with 5% rhodium

on carbon in ethyl acetate, a compound was isolated and purified and

assigned structure 114. The nmr spectrum showed an absence of the







11 2
,CH20H


CH20H
0
114

quinodial protons of the starting material and gave resonances at

64.29 (singlet, allylic hydrogens adjacent to hydroxyl, 4), 64.10

(singlet, allylic hydrogens, 4), 63.87 (singlet, broadened, hydroxyl

hydrogens) and 62.60 (singlet, hydrogens adjacent to carbonyl, 4).










In a hydrogenation attempt under more forcing conditions, i.e.,

5% rhodium on carbon at 35 psi., a white crystalline solid was isolated

that melted at 151-40C. The nmr spectrum was indicative of structure

115 which could result from the hydrogenolysis of a carbon nitrogen

bond. The resonance signals recorded were 64.31 and 64.13 (two over-

lapping broad singlets, allylic hydrogens, 4), 62.65 (singlet, hydrogens

adjacent to the carbonyls, 4) and 61.75 (broad singlet, allylic methyl

hydrogens, 3). The mass spectrum gave the correct parent peak at

m/e 228 and the base peak at m/e 210.


0
H CH 3
--CH2OH

11 2
0
115

The resistance to hydrogenation of the tetrasubstituted double

bond was not surprising since at least one report of a similar case
74
is documented in the chemical literature. Gillis and Beck attempted

to hydrogenate 116 with Pd/C, Rainey nickel and Pd/Al2)3 at 59 psi

and were unsuccessful.


0
-COC2CH3
/N-^ 0CH2CH3
xJ-qOCH 2 Ctl3


116


Hydrogenation of the double bonds of compound 90 was recognized

as another route to 24. At atmospheric pressure hydrogenation with

5% rhodium on carbon in ethyl acetate resulted in the absorption










TABLE 7. CATALYTIC HYDROGENATION OF DIAZOQUINONE ADDUCTS


Conditions

Rh/C, ethyl acetate
atmospheric pressure
"


Experiment

1


2

3

4


5


6


Substrate

108a


108a

108b

108b


108b


108b


Product

unidentified oil
2250 cm.-1 ir



114

unidentified oil
2250 cm.-1 ir




unidentified oil


115


of one third the theoretical amount of hydrogen. On work up a white

solid was obtained with all spectral characteristics identical to its

hydroquinone derivative 91.



Attempt to prepare precursor to intramolecular Diels Alder pathway

27, the Diels Alder adduct of 2,3-di(bromomethyl)l,3-butadiene

and p-benzoquinone, was smoothly prepared by the method of Butler and
29
Ottenbrite.29 The 1,4-elimination of bromine from this compound by

the use of zinc in dimethylformamide28 to yield 28 was unsuccessful.

Attempts to trap the intermediate diene with maleic anhydride and

tetracyanoethylene were unsuccessful. In each case unidentifiable

soluble polymeric material was obtained. Since Alder and Fremery28

had postulated diradical-intermediates in their investigation of the

zinc dimethylformamide system, it is possible that the diene formed

but then quickly polymerized.


Rh/C, ethyl
atmospheric

Pd/C, ethyl
atmospheric

Pd/C, ethyl
atmospheric

Rh/C, ethyl
35 psi


alcohol
pressure

alcohol
pressure

acetate
pressure

acetate


108b









B. Attempted Synthesis of 5,5,6,6-Tetrasubstituted Cyclohexadiene

Structures

Proposed syntheses

Two synthetic routes were investigated as possible means to

generate 5,5,6,6-tetracyanocyclohexadiene, 29. Earlier work75 had

shown that the Diels Alder adduct of butadiene and tetracyanoethylene,

117, was resistant to halogenation reactions. The routes investigated


CN CH3 CH3

-CN FA
-\N 1

117 118 119


were the reaction of tetracyanoethylone with a-pyrone, 118, and with

3,4-dimethylthiophene-l,l-dioxide, 119, and then subsequent loss of

carbon dioxide or sulfur dioxide to the desired tetrasubstituted diene.



Adducts of a-pyrone

118 was synthesized by the excellent preparation of Zimmerman and
76
coworkers. Surprisingly the cisoid diene failed to form the desired

Diels Alder adduct with tetracyanoethylene under a variety of conditions.

Upon mixing the two reactants, a strong reddish-brown color was always

observed; however either starting materials or black tars were re-

covered from each reaction as summarized in Table 8.

The failure of tetracyanoethylene to form a Diels Alder adduct

with 118 is surprising since this diene has been observed to be quite

reactive with rather unreactive dienophiles. Fieser and Haddadin77

observed 118 to react with the unusual dienophile 120 to yield 121.












0 1180 0-

0


120 121



Diels and Alder78 observed the formation of the Diels Alder adduct

with maleic anhydride. This reaction was successfully repeated.

Successful Diels Alder additions of 118 with both p-benzoquinone

and fumaronitrile to yield 122 and 123 were observed. 122 was

C0
S0 0--0




122 0 123

-1
characterized by the infrared spectrum which gave both a 1750 cm.
-l
ester carbonyl and a 1655 cm.- quinone carbonyl. The nmr spectrum

yielded resonances at 66.82 (singlet, quinone hydrogens, 2) 66.57

(triplet, vinylic hydrogens, 2), 65.69 (quartet, allylic hydrogens

next to oxygen, 1), 64.21 (quartet, hydrogen next to carbonyl, 1) and

63.60 (two doublets, bridgehead hydrogens, 2). The elemental analysis

was satisfactory for 122.

The fumaronitrile adduct, 123, gave weak infrared absorbances

for the nitrile groups at 2245 cm.-1 and 2200 en.-I The ester
-l
carbonyl absorbance was at 1755 cm.- The nmr spectrum gave resonances

at 66.92 multiplee, vinylic hydrogen, 2), 65.80 multiplee, hydrogen

adjacent to oxygen, 1), 64.08 multiplee, unassigned, 2) and 63.63










multiplee, unassigned, 1). A correct elemental analysis was obtained.

Both dimethyl maleic anhydride and tetraethylethylenetetracarboxyl-

ate failed to form the Diels Alder adduct also. It is probable that

tetracyanoethylene along with these two dienophiles failed to react

because of steric interference. Under the forcing conditions, where

the tars were obtained, it is possible that the adduct formed, lost

carbon dioxide and then the resulting diene thermally polymerized

under the severe reaction conditions.



Adducts of 3,4-dimethylthiophene-l,l-dioxide

3,4-Dimethylthiophene-l,l-dioxide, 119, was prepared by first

the bromination of 2,3-dimethylbutadiene sulfone, 82 to the dibromide

124 and then dehydrohalogenation with sodium methoxide in tetrahydro-

furan. The results of this reaction were not reproducible. Sometimes

119, the desired product, was formed in good yield, while at other times
79
125 was formed. The literature preparation of 119 involved oxidation


CH3 CH3
Br -Br YH3


02 02

124 125

of the corresponding thiophene to the thiophene dioxide. A reported

dehydrobromination80 of 124 with potassium hydroxide only yielded 125.

119 was found to be unreactive with tetracyanoethylene in the

same manner as was a-pyrone. However, maleic anhydride reacted with

119 in refluxing toluene'to form 126.

This compound was identified by its infrared spectrum with an










TABLE 8. REACTIONS OF TETRACYANOETHYLENE WITH a-PYRONE


Experiment


Solvent


neat

tetrahydrofuran

neat
XS pyrone

neat

xylene

toluene

benzene

tetrahydrofuran


anhydride carbonyl 1850 cm.-L
anhydride carbonyl 1350 cia.


and 1780 cm.-1
and 1780 cm.


The nmr spectrum exhibited


resonance signals at 63.55 (siOglet, broad, hydrogen adjacent to

carbonyl, 4), 63.20 (singlet, broad, hydrogens at bridgehead, 2) and

61.62 (singlet, allylic methyl hydrogen, 6). The mass spectrum

yielded a molecular ion at m/e 276.


Temperature Time
(hrs)

ambient 72

reflux 48

140C 2
reflux

100C 24

reflux 48

reflux 44

reflux 45

sealed
tube 600 188


Product


no reaction

no reaction

black tar


black

black

black

black


no reaction
















CHAPTER IV


Experimental

A. General

All melting points and boiling points are uncorrected and reported

in degrees centigrade. Melting points were determined in open capil-

lary tubes on a Thomas-Hoover capillary melting point apparatus.

Pressures are reported in millimeters of mercury. Elemental analyses

were done by Galbraith Laboratories, Inc., Knoxville, Tennessee,

Peninsular ChemResearch, Inc., Gainesville, Florida or Atlantic Micro-

lab, Inc., Atlanta, Georgia.

Infrared spectra were recorded with either a Beckman IR 10 or

a Beckman IR 8 Spectrophotometer. Visible spectra were recorded on

a Beckman DK-2A Spectrophotometer. Proton nuclear magnetic spectra

were obtained by use of a Varian A-60 Spectrometer and all resonances

are given in the chemical shift parameter 6 and are measured from

tetramethylsilane (TMS) as an internal standard. Mass spectral data

were obtained using a Hitachi Perkin-Elmer RMN mass spectrometer.

All solvents were commercial reagent grade and used as received

unless specifically noted. Polymer nonsolvents were technical grade

and were filtered before use. All chemicals used as reactants were

obtained commercially and used as received unless specifically

designated as otherwise.

The comonomers divinyl ether, ethyl vinyl ether, isobutyl vinyl

ether, styrene, acrylonitrile, divinyl sulfone and vinyl acetate were










obtained from commercial sources and distilled immediately prior to use.

Divinyl carbonate and N-vinyl carbazole were obtained in high purity

from commercial sources and used without further purification.

Number average molecular weights were obtained from a Mechrolab

Model 302 Vapor Pressure Osmometer. Molecular weight distributions

were obtained from a Waters Associates GPC 300 Gel Permeation Chromato-

graph. Thermal characteristics of the polymers were recorded by a

Perkin-Elmer DSClB Differential Scanning Calorimeter. Intrinsic

viscosities were measured employing a Cannon-Ubbelohde semimicro

dilution viscometer using standard procedures for operation and

calculations.



B. Copolymerizations and Related Reactions of 4-Substituted 1,2,4-

triazoline-3,5-diones

1. Synthesis of 4-phenyl and 4-methyl-l,2,4-triazoline-3,5-diones
81
Ethyl carbazate -Diethyl carbonate (2Q00 g., 1.80 mol.). and

88.0 g. (1.80 mol.) of 99% hydrazine hydrate were shaken together

for approximately 20 minutes. Some exothermicity was observed and

after this time the original two phase system blended into one phase.

The solution was left standing overnight. Distillation at 95C and

12 mm. yielded 147.7 g. (83.5%) of a clear liquid which solidified

on standing to a white solid, m.p. 43-45.5 (lit.81 44-45.5).
82
l-Ethoxycarbonyl-4-phenylsemicarbazide -Ethyl carbazate (70.0 g.,

0.67 mol.) was placed into a 500 ml. round-bottomed, three-necked

flask with 350 ml. of benzene. The flask was equipped with a magnetic

stirrer, a reflux condenser guarded by a calcium chloride drying tube,

a dropping funnel and a thermometer. After refluxing to get the










ethyl carbazate into solution, the solution was cooled to 10. Through

the dropping funnel 70.0 g. (0.59 mol.) of phonyl isocyanatewere intro-

duced at a rate -.hich kept the temperature between 100 and 200. After

all the isocyanate was added, the resulting white solid slurry was

refluxed for 20 minutes and then cooled and filtered. After drying

under vacuum 124 g. (89%) of the desired product m.p. 152-3' (lit.82

m.p. 154') were obtained.

4-Phenyl urazole82-To 275 ml. of hot 4M potassium hydroxide, 124 g.

(0.55 mol.) of l-ethoxycarbonyl-4-phenylsemicarbazide were added in

small portions while shaking the potassium hydroxide solution on a

steam bath. After the addition was completed, the solution was main-

tained on the steam bath for an additional 20 minutes. The solution

was cooled and carefully acidified with concentrated hydrochloric

acid. The precipitate was removed by vacu-um filtration and extracted

with 95% ethyl alcohol via a Soxhlet extractor. On cooling and then

treating the mother liquor 69.2 g. (70.3% yield) of the urazole m.p.
82
204-7' (lit. 82.p. 206-7') was obtained.

4-Phenyl-l,2,4-triazolina-3,5-dione, PhTD -Anhydrous sodium

sulfate, 25.0 g., was placed into a 500 ml. Erlenmeyer flask with

300 ml. of methylene chloride and 6.0 g. (0.034 mol.) of 4-phenyl

urazole. The slurry was stirred by a magnetic stirrer and cooled to

0-5' with an ice-water bath. By means of a pipette attached to a gas

cylinder with a tube, dinitrogen tetroxide was bubbled slowly through

the solution. The temperature was kept below 5'. after a few minutes

a deep red color developed. After all the urazole appeared to have

been consumed, usually in about thirty minutes, the sodium sulfate

was removed by vacuum filtration and the deep red solution was









evaporated using lukewarm water on a rotary evaporator. 4.8 g. (80%

yield) of dark red crystalline PhTD was obtained. Purification was ac-

complished by sublimation at 70-750 under a vacuum of less than 0.5 nn.

The red solid was stored in the absence of light in a freezer until it

was used.

4-Methyl-l,2,4-triazoline-3,5-dione, MTD -The same procedure used

in the synthesis of PhTD was employed in the synthesis of MTD. This
83
synthesis had been previously reported in the literature.83 ethyl iso-

cyanate was added to the ethyl carbazate and a quantitative yield of the

corresponding semicarbazide derivative was obtained. This was cyclized

with 4M potassium hydroxide to the corresponding 4-methyl urazole in a

yield comparable to the phenyl derivative. Oxidation with dinitrogen

tetroxide was accomplished in approximately 90% yield. The light red

fluorescent appearing powder was purified by sublimination at less than

0.1 mm. and a temperature between 50 and 60.



2. General copolymerization procedures

a. Spontaneous copolymerizations

The following experimental procedure was typical of all spontaneous,

room temperature ccpolymerizations unless specifically noted otherwise.

All glassware, i.e., Erlenmeyer flasks, syringes and volumetric

flasks were scrupulously cleaned, rinsed with acetone, dried in an 80*

oven and then allowed to cool to room temperature in a large desiccator.

On removal from the desiccator the flasks were immediately capped with

serum caps. Solvents were reagent grade and dried for a minimum of 24

hours over 3A molecular sieves.

Ethyl vinyl ether, EVE, PhTD copolymerization-A 50 ml. Erlenmeyer









flask equipped with a magnetic stirring bar and a rubber serum cap was

charged with 0.499 g. (2.84 mmol.) of PhTD by removing the cap and adding

as a solid. Next, 15 ml. of methylene chloride were introduced using a

syringe and adding through the serum cap. This was followed by the add-

ition of EVE (0.203 g., 2.83 mmol.) in the following manner. The vinyl

ether was carefully weighed into a 10 ml. volumetric flask through a

serum cap and then the flask was brought to volume with methylene

chloride. A careful quantitative transfer to the reaction vessel was

made using a syringe. The reaction mixture was stirred and within two

minutes the dark red colored solution, characteristic of PhTD, was

discharged to yellow. After 30 minutes the reaction mixture was pre-

cipitated by dropping slowly through a coarse filter frit into cold

hexane. The hexane solution was filtered to yield 0.615 g. (86% yield)

of a white-yellowish granular appearing solid. The solid appeared to

soften at 1000 and above 1500 it darkened and decomposed. The number

average molecular weight was determined to be 1660 by use of a Vapor

Pressure Osmometer in acetone solution. The infrared spectrum (KBr)

showed absorbances at 2980 (w), 1770 (w), 1715 (s), 1610 (s), 1500 (m),

1470 (m), 1420 (n), 1310 (m), 1130 (n), 1070 (w), 900 (w), 820 (w),

760 (m) and 700 (m) cm.I The nmr spectrum (CDC3 ) gave resonance

signals at 67.45 (s, broadened, 5), 66.00 (m, broad, 1), 63.83 (m, broad)

and 61.16 (t, broad, 3). The spectrum is shown in Fig. 1.

Anal. Calcd. for a 1:1 copolymer structure, C12 H3N303: C, 58.30;

H, 5.26; N, 17.00. Found: C, 58.08; H, 5.14; N, 17.16.

Table 1 contains a summary of experimental results of all EVE-

PhTD copolymerizations.









b. Copolymerizations at 600

The following experimental procedure was typical of all copolymer-

izations at 60 unless specifically noted otherwise.

The copolymerizations were effected in heavy walled 13 cm. x 3 cm.

Pyrex tubes. All glassware i.e., Pyrex tubes, syringes and volumetric

flasks was thoroughly cleaned, rinsed with acetone, dried in an 80"

oven and then allowed to cool to room temperature in a large desiccator.

On removal from the desiccator the volumetric flasks and the polymer

tubes were sealed with serum caps. Solvents were reagent grade and

were dried for a minimum of 24 hours over 3A molecular sieves. Copolymer-

izations were conducted in a 600 oil bath regulated by a Sargent NS1-

12 controller to 0.1.

Copolymerization of divinyl ether, DVE, and PhTD at 60-A heavy

walled Pyrex polymer tube, capped with a serum cap, was charged with

0.508 g. (2.81 mmol.) of PhTD by removing the cap and adding the solid.

This was followed by the addition of 15 ml. of methylene chloride by.

means of a syringe. Next DVE (0.200 g., 2.82 immol.) was carefully

weighed into a 10 ml. volumetric flask using a syringe and adding

through a serum cap. The flask was brought to volume with methylene

chloride and then carefully transferred to the polymer tube by means of

a syringe. The polymer tube was then placed on the high vacuum line
-4
and carried through a freeze-thaw degassing cycle using a 10 mm.

vacuum. The tube was sealed and warmed to room temperature before

placing in the 600 bath. After 24 hours at 600 the originally red

colored solution had changed to yellow. This color change normally

took place within a few minutes after placing the tube in the bath. The

tube was removed from the oil bath after 24 hours, cooled to room temp-




Full Text

PAGE 1

POLYMERIZATION STUDIES OF 4-SUBSTITUTED-l,2,4-TRIAZOLINE-3,5-DIONES AND SYNTHESIS OF MODEL COMPOUNDS RELATED TO TRIPLE STRAND POLYMERS By SAM RICHARD TURNER A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1971

PAGE 2

This dissertation is dedicated to my parents,

PAGE 3

AC KNOWLEDGEMENT S My stay at the University of Florida has been a pleasant and rewarding experience and I would like to offer my gratitude to the many people who have made this experience possible. I will be forever indebted to my advisor, Dr. George B. Butler, for his patience, understanding, encouragement and guidance during the course of this work. I wish to thank Dr. W. R. Dolbier, Dr. J. A. Deyrup , Dr. M. T. Vala and Dr. R. B. Bennett for giving of their valuable time to serve on my supervisory committee. Also I wish to thank Dr. T. Hogen Esch for his informing discussions with me on portions of this work. The successful completion of this work would not have been possible without the assistance of Dr. Lawrence J. Guilbault. His enthusiastic and tireless research efforts have been and will always be a great example for me. Grateful thanks are extended to my fellow laboratory colleagues. They have generated a pleasant and stimulating environment in which to work. I also wish to acknowledge the Air Force Office of Scientific Research, the Petroleum Research Fund and the Tennessee Eastman Company for providing financial support in the form of research assistantships . Finally, I wish to thank my wife, Pamela, for her love and understanding which have made the completion of this work an easier task.

PAGE 4

TABLE OF CONTENTS Page ACKNOWLEDGEMENTS x±x LIST OF TABLES v LIST OF FIGURES vi ABSTRACT vii CHAPTER I. INTRODUCTION 1 A. Polymerization Studies of: Azo Dienophiles .... *• B. Triple Strand Polymer Model Compound Studies . . 9 II. POLYMERIZATION STUDIES OF 4-SUBSTITUTED-l,2 ,4TRIAZOLINE-3,5-DIONES 14 A. Copolymerization of Ethyl Vinyl Ether and Divinyl Ether with 4-Phenyl-l ,2 ,4-triazoline-3,5-dione . 14 B. Copolymerization of 4-Phenyl-l,2,4-Triazoline3,5-dione with Other Monomers ^ C. Reactions and Attempted Homopolymerizations of 4-Phenyl-l,2 ,4 -triazoline-3,5-dione ^3 D. Diels Alder Polymers ->8 III. TRIPLE STRAND POLYMER MODEL COMPOUND STUDIES .... 66 A. Attempted Synthesis of Tetracyclo[4 .4 .0. 1 ' .1 ' ] Dodecane and Related Systems "" B. Attempted Synthesis of 5 ,5 ,6,6-Tetrasubstituted Cyclohexadiene Structures IV. EXPERIMENTAL 86 A. General 86 B. Copolymer izations and Related Reactions of 4Substituted-l,2,4-triazoline-3,5-diones C. Syntheses Related to Triple Strand Model Compound p ; ,, 121 Studies REFERENCES CITED 153 BIOGRAPHICAL SKETCH 157

PAGE 5

LIST OF' TABLES Table Page 1 Copolymerizations of EVE and PhTD 29 2 Copolymerizations of DVE and PhTD 31 3 First Order Rate Constants in PhTD at 25°C 37 4 Summary of Interception Reaction Results ....... 43 5 Copolymerizations and Reactions of PhTD and Other Monomers 47 6 Summary of Catalyzed PhTD Reactions 57 7 Catalytic Hydrogenation of Diazoquinone Adducts .... 81 8 Reactions of Tetracyanoethylene with cx-Pyrone 85

PAGE 6

LIST OF FIGURES Figure Page 1 Nmr spectrum of the copolymer of ethyl vinyl ether and 4-phenyl-l,2 , 4-triazoline-3,5-dione 16 2 Nmr spectrum of 3-phenyl-6-vinyloxy-l ,3,5-triazabicyclo[3.2.0]hepta-2,4-dione 18 3 Nmr spectrum of the copolymer of divinyl ether and 4-phenyl-l,2 ,4-triazoline-3,5-dione 21 4 Nmr spectrum of the copolymer of divinyl ether and 4-methyl-l ,2 ,4-triazoline-3,5-dione 22 5 Plot of M versus reaction time, for EVE-PhTD in CH„C1„ at 25°C ? z . ? . . 34 6 Nmr spectrum of 3-oxa-2,2-diraethyl-4-ethoxy-8-phenyl1,6,8-triazabicyclo [4 .3. 0]nona-7 ,9-dione 38 7 Nmr spectrum of l-(f ormylmethyl)-2-acetyl-4~phenyl1,2 ,4-triazoline-3,5-dione 49 8 Nmr spectrum of the Diels Alder, ene adduct of 4-phenyl1,2 ,4-triazoline-3,5-dione and styrene 63 9 Nmr spectrum of the Diels Alder, ene polymer from styrene and bis triazoline dione 64 10 Plot of consumption of PhTD versus time for EVE-PhTD in dioxane at 25°C 110 11 Logarithmic plot of [PhTD] /[PhTD or A /A versus time for EVE-PhTD in dioxane at 25°8 ° Ill

PAGE 7

Abstract of Dissertation Presented to the Graduate Council of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy POLYMERIZATION STUDIES OF 4-SUBSTITUTED-l,2,4-TRIAZ0LINE-3,5-DI0NES AND SYNTHESIS OF MODEL COMPOUNDS RELATED TO TRIPLE STRAND POLYMERS By Sam Richard Turner June, 1971 Chairman: Dr. George B. Butler Major Department: Chemistry The research described in this dissertation consists of two main areas of investigation. The first area pertains to the use of azu dienophiles, particularly 4-phenyl-l,2,4-triazoline-3,5-dione, in polymerization studies. The second area involves attempts to synthesize model compounds related to proposed triple strand polymers. A. Polymerization Studies of 4-Substituted-l ,2 ,4-t riazoline-3 ,5diones The copolymerization and reactivity of the very potent cyclodienophile, 4-phenyl-l,2,4-triazoline-3,5-dione (PhTD), with electron rich coreactants were investigated. PhTD was found to. spontaneously react with vinyl ethers at room temperature in methylene chloride solution. Ethyl vinyl ether (EVE) and isobutyl vinyl ether (IVE) were observed to copolymerize spontaneously with PhTD to form 1:1 alternating copolymers. Divinyl ether (DVE) was observed to form a mixture of the 2+2 cycloadduct and copolymer at room temperature. At 60°C, only copolymer was formed . The structures of the copolymers were assigned from spectroscopic and chemical data! Some physical property characterizations of the

PAGE 8

copolymers were Bade. A propagation mechanism involving the coupling of dipolar inter-^ mediates was ascertained as the most probable mechanism of polymerization. . Numerous experimental observations were in support of this proposed method of polymerization. When the spontaneous copolymerizations of EVE and 1VE were effected in acetone or eyclohexanone, the corresponding 1,3,4-tetrahydrooxadiazine compounds were obtained as well as the expected copolymers. These new heterocyclic ring structures were fully characterized. The compounds were believed to result from an interception of the initial 1,4dipole intermediate by the weakly dipolarophilic alkyl ketone. DVE was noted to form only a trace of the corresponding oxadiazine structure. The difference in the reactivity of EVE and DVE was explained in terms of the stability of the positive center of the 1,4-dipole. Other olefinic compounds were reacted with PhTD. Vinyl acetate was observed to undergo a unique intramolecular rearrangement of the initially formed 1,4-dipole. Divinyl carbonate only resulted in 2:1 copolymers. N-vinyl carbazole spontaneously copolymerized to yield a 1:1 copolymer of significantly higher molecular weight than obtained in the vinyl ethers. The electron poor olefins, divinyl sulfone and acrylonitrile, were found to be unreactive with PhTD. Some decomposition reactions of PhTD were studied. Attempts to catalytically homopolymerize PhTD were unsuccessful. The reaction of PhTD with nucJeophiles like sodium cyanide in dimethylf ormamide and triethylamine resulted in the formation of 3,7-diphenyl-l,5-diazabicyclo[3.3.0]octa-2,4,6,8-tetraone as well as an unidentified oligomeric product. viii

PAGE 9

A new bis dienophile, 4,4 , ^C4,4 t -diphenylmethylene)-his--l,2,4-* triazoline—3 } 5-dione, for use in cycloaddition polymerizations was synthesized. It was found to spontaneously react with, styrene to give, a high, polymer believed to have been formed by first a Diels Alder reaction and then an ene reaction. B. Synthesis of Model Compounds Related to Triple Strand Polymers Two dienes, 2-acetoxymethyl-l,3-butadiene and 2 , 3-di-(acetoxymethyl)-l,3-butadiene 3 were synthesized by a new sulfone pyrolysis pro• cedure. The precursor acetoxy sulfones were prepared in good yields from the corresponding bromides by use of silver acetate in acetonitrile. The Diels Alder reactions of these acetoxy dienes and the corresponding dihydroxy diene from the 2 , 3-diacetoxy diene were studied with p-benzoquinone. A facile aronatization or dehydrogenation of the adduct, depending on the conditions, precluded its isolation. 2-Cyclohexene-l-one was found to react sluggishly with the 2acetoxymethyl diene. Attempts to force the reaction yielded polymeric materials. Diazoquinone reacted with the disubstituted dienes to yield the expected Diels Alder adducts. Various attempts at catalytic hydrogenation of these adducts were not successful. Tetracyanoethylene was found to be unreactive with a-pyrone. Fumaronitrile and p-benzoquinone resulted in the expected adducts. Bromination of 3,4-dimethylbutadiene sulfone and then dehydrobromination resulted in the corresponding 3,4-dimethyithiophene-l,l-dioxide. This compound was found to be unreactive with tetracyanoeth— ylene, but it gave a double Diels Alder adduct with maleic anhydride.

PAGE 10

CHAPTER I "In troducti on A. Polymer ization Studie s of Azo Dieixophi.les Reac tivity of azo dienophiJ.es Compounds containing dienophillc nitrogen to nitrogen double bonds have been extensively studied as reactants in cycloaddition reactions. Normally these azo compounds have been shown to be more dienophilic than their carbon counterparts. For example azodicarboxylates , 1, have a stronger dienophilic reactivity than the corresponding f uraarates , 2_. N=N C °2 R • H C=c£°2 R R0 2 C R0 2 C H However, at the time this research was initiated only one report of the use. of these compounds as monomers in polymerization studies was 2 recorded. This account involved the copolymerization of ethyl azobisformate with the comonomers tetraf luoroethylene, acrylonitrile and methyl methacrylate. In each case some incorporation of the azo compound into the polymer was verified by elemental analysis. No other structural characteristics were reported. 4-Phenyl-l,2 ,4-triazoline-3,5-dione (PhTD) , 3, has been shown by Sauer and Schroder to be the most reactive of the azo dienophiles and perhaps the most reactive dienophile known. The authors compared the reactivity of PhTD with tetracyanoethylene by utilizing competition experiments with 2-chloro-l ,3-butadiene. PhTD was observed to react

PAGE 11

about one thousand times faster than tetracyanoethylene, which bad been 4 previously described as one of the most potent dienophiles synthesized. With the same diene, maleic anhydride, 4_, was found to react only about one half as fast as the tetracyanoethylene. Hov.ever, with other dienes tetracyanoethylene reacted as great as 10 times faster than 4_. Copolymer ization studies The structure of 4-substituted-l,2 ,4-triazoline-3,5 diones is very similar to that of the carbon to carbon double bond dienophiles maleic anhydride and N-substituted maleimides, _5. The latter compounds have been utilized extensively as comonomers in copolyraerization studies. It was expected, then, "a priori" that these nitrogen analogues of maleic H HH K N— N C — C C=C' =0*° 0-O*o otiMo Ph R 3 4 5 anhydride and the maleimides would undergo similar copolymerizations with the appropriate electron rich comonomer. Cyclocopolymerization, originally reported by Butler, has evolved as an extremely important research area in polymer chemistry, not only because of the theoretical significance of the reaction but in the main because some of the cyclocopolymers have been shown to be active antitumor agents. Because of this importance, the mechanistic and preparative aspects of cyclocopolymerization have undergone a careful systematic study. The general mechanism proposed was that of an alternating intra-inter molecular propagation as shown below for the divinyl ether maleic anhydride system which is the most thoroughly studied of all the

PAGE 12

cyclocopolymerization -systems . Since the initial mechanistic proposal, evidence consistent with the participation of a donor acceptor complex R* x '. " " R ' S)/^ °'\o^° o>\ ^o -"V ' \ o^ A-o as a comonomer has been presented. More recently the divinyl ether maleic anhydride system has been observed to polymerize thermally in 9 the absence of a free radical initiator and this has been interpreted as additional evidence for the participation of a donor acceptor complex in the copolymer ization. Since 4-substituted-l,2 ,4-triazoline-3,5-diones are known to be better dienophiles than the usual electron poor comonomers in cyclocopolymerization, it was thought that they might behave as electron acceptors in the presence of electron rich 1,4-dienes and participate in cyclocopolymerization. Furthermore, it seemed a distinct possibility, because of their great reactivity, that a spontaneous cyclocopolymerization might possibly be triggered. The degradation approach to proving polymer structures is important.

PAGE 13

For example, the cyclic structure resulting from the copolymerization of diallyl quaternary ammonium salts was verified by the follox^ing degradation procedure. cm ch 1. to hydroxide 2. heat to hydroxide 13. heat (CH 3 ) 3 N crossl inked polymer No such proof of the cyclic structure of the cyclocopolymer systems has been possible to this time. If a 2:1 cyclocopolymer were to form, the unique characteristics of the triazoline dione moiety would offer a convenient handle to chemically probe the polymer structure by the general degradation procedure shown below. N~ N. Ph Ph base / 0N-N, H H -N— Ni i H H 1. [0] A low molecular weight products For the preceding reasons as well as the desire to build new cyclic copolymer structures to be tested as anticancer agents, the behavior of 4-substituted-l,2 ,4-triazoline-3,5-diones with electron rich olefins was investigated. Nitrogen backboned polymer s At the commencement of this research no nitrogen backboned polymer had ever been reported. If homopolymerization of an azo dienophile

PAGE 14

could be effected through the nitrogen to nitrogen double bond, obviously such a polymer with a nitrogen backbone xrould result. A report by Huisgen of the participation of ethylazobisf ormate in a substitution reaction with fluorene proceeding by a free radical chain mechanism made a free radical polymerization of such an azo dienophile an attractive possibility. ^ in R= --C0 2 CH 2 CH 3 H N— N By envisioning the results of such a successful polymerization of a 4-substituted-l,2 ,4-triazoline-3,5-dione , one would have at hand structure 6. Since such structures are readily hydrolyzable in strong .N— N k J n base, a polyhydrazine structure, 7_, would be distinctly possible. These nitrogen backboned structures might possess practical value as well as, assuredly, possessing theoretical importance. As another --Ni 11

PAGE 15

goal of this research, the homopolymerization of 4-substituted— 1,2 ,4triazoline3,5-diones, was investigated. 12 In the course of this work, Pirkle and Stickler reported the homopolymerization of 4-n-butyl-l ,2 ,4-triazo. 1 ine-3,5'dione by initiation with visible irradiation. These authors presented strong evidence that the polymer obtained, indeed, possessed a nitrogen backbone. Di els Alder polymers Although the number of chemical reactions investigated in organic chemistry is immense, those that have been successfully adapted to yield high polymers are few. Two types of cycloaddition reactions have met with considerable success in producing high polymers, i.e., 13 14 1,3-dipolar cycloadditions and Diels Alder reactions. The Diels Alder reaction has developed into the most profitable 14 application of the use of cycloaddition reactions to form polymers. To adapt the Diels Alder reaction to a polymer forming system whereby the polymer is built up by stepwise Diels Alder cycloadditions requires that the reactants be made difunctional. Two different approaches have been utilized. The first involves the reaction of a bis diene and a bis dienophile, generally referred to as an A-A, B-B system. One example is the reaction of p-benzoquinone, j3, with the acetal prepared from 2~hydroxymethyl-l,3-butadiene and acetaldehyde , 9_. 5 -CH 2 0C1L H CH OCOCH CH 3

PAGE 16

The second general approach has utilized an A— B monomer or an intramolecular diene, dienophile. The reaction of the substituted a-^pyrone, 10, and p-phenylene bismaleimide, 11, is a good example of 16 this approach. 0^ .. J-COCH.. \ ^ •> I 2 10 -;• en. CK„CH„0C 6 l 6 0)~{J 6' 11 o R N CH -Tfi V I O CH CH OCX// 6 ,N-R-N polymer The main limitation and drawback to the use of the Diels Alder reaction has been the difficulty in obtaining high molecular weight products. in a polymerization propagation that follows step growth kinetics, as is the case in a Diels Alder polymerization, the degree of polymerization DP follows the Carothers equation DP = l/l-p, where p is the extent of reaction. This means that the reaction must be practically quantitative before a high molecular weight product is obtained. For example a reaction with a 98% conversion only yields a DP of 50 or, in other words, a low average molecular weight. Hence, any stepwise polymerization reaction that is subject to side reactions of any significance will not be suitable for formation of high molecular weight products. Two main reasons have been put forth for the inability, in most instances, of Diels Alder polymerizations to achieve high molecular 19 weights. ' The first involves the ease by which the retrodiene

PAGE 17

reaction can occur and the second concerns the chain growth of the diene under the reaction conditions. Another complicating factor in some systems has been the precipitation of the rigid ladder type polymer causing a premature termination. Since the Diels Alder reaction is a thermally catalyzed reaction and these two complicating factors also are enhanced at higher temperatures, it is not surprising that the problem of obtaining high molecular weight has plagued its use in producing high polymers. 20 Stille and coworkers have successfully circumvented the retrodiene reaction by employing bis dienes such as bis a-pyrones and bis cyclopentadienones that lose carbon dioxide or carbon monoxide respectively and hence prevent the degradative retrodiene reaction from occurring. An example has been the 'successful use of 3 ,3' -(oxydi-pphenylene)bis (2 ,4 ,5-triphenylcyclopentadienone) , 12_, and p-phenylene 20 bismaleimide , 11. A polymer with an intrinsic viscosity of 1.01 was obtained in four hours in refluxing 1,2 ,4-trichlorobenzene. 1'h '-br© 1 1 Ph Ph _0 + 11 12 Ph 1 1 ' "CsPh ii T Ph Ph0>-o-(0>— ^ Ph -> Ph r(0 —i n Another possible route to circumvent the bothersome side reactions would be to employ extremely reactive reactants that would not need to

PAGE 18

be heated in order to obtain the necessary high conversions. Obviously, a bis 1 ,2 ,4-triazoline— 3,5-dione would be expected to serve in this capacity because of its fantastic reactivity. Hence another objective of this research was the synthesis, and polyneriration with bis dienes, of such bis dienophiles. B. T riple S trand Polymer Model Compound Studies Th ermal stabi lity of ladder polymers The synthesis and study of thermally stable polymers have been extremely active areas of polymer chemistry research in recent years. The extensive accounts cf such research recorded in the chemical literature attests to the theoretical and practical importance of this work. No attempts will be made to rev lev/ these accounts since a recent i ,21 . 22,23,24 ... ., book and several reviews are readily available. Physical polymer properties have generally been found to be related to the molecular weight of the polymer. These structureproperty correlations have established that polymers with ladder or double strand structures, 1A_, possess extremely high thermal stability For example polydiallydiphenysilane, having structure 13 was observed to have enhanced thermal stability over its non-cyclic counterpart 2 3 H 5 C 6 \ U 5 25 13 prepared from the monoallyl derivative.. The reason advanced for the thermal stability of such cyclic structures is that thermal bond

PAGE 19

10 cleavage which occurs -within the cyclic polymer repeat units of the backbone does not lead to a lower molecular weight polymer. It is obvious that thermal bond cleavage in the non-cyclic structures results in a lower molecular weight as depicted in .Ha and 14b . S 14a 14b Therefore one goal that the polymer architect has striven for in the design of materials possessing thermal stability has been the synthesis of ladder or double strand polymers. Needless to say, many different researchers have been successful in using the double strand polymer concept in preparing materials resistant to thermal breakdown. Possible tri ple strand polyme rs As an extension of the ladder polymer concept of thermal stability a triple strand polymer would be expected to possess thermal properties reflected from a structure that requires three bond cleavages per ring to cause a decrease in molecular weight. Two possible approaches to constructing such a polymeric species are: 1) a formation of a tubular polycyclohexane, 15, from a triply initiated chain reaction of benzene SE 15 and 2) a triple 1,4-polymerization of a monomer such as 16^ to yield structure 17.

PAGE 20

11 16 17 Model comp oun d stu dies Generally, one of the objectives of this research was the preparation and studies of model compounds related to these two possible routes envisioned to triple strand polymers. Much effort has been extended in the attempted synthesis of 3 9 4 8 tetracyclo [4.4.0.1 ' .1 ' ]dodecane, 18^ the repeat unit of the tubular polycyclohexane polymer. 18 The first approach has involved the homo Diels Alder reaction of 26a cis 4,5-diallylcyclohexene derivatives, 19_. To date this approach has not been successful. 18 Sis 19 The second approach has utilized 1 ,3,5-trisubstituted cyclohexane

PAGE 21

12 derivatives 20 and 21. The trl ester 21 has been successfully prepared and failed to undergo the desired cyclization to L8. 26ti A compound, which would lead to a nitrogen analogue of 18, _2_2, has been successfully prepared but also failed to yield' the cyclic structure 23. 2/ — >18 20 "0=C?N N-C-0 R= -CH 2 C0 2 CH 2 CH 18 18 21! 23 The synthesis of compounds such as 24, which are functionally capable of undergoing an intramolecular base catalyzed cyclization, is the basis of the third approach to 18_. One objective of this work Oir Co CH OMs base. CH 2 OKs 24 18 was the preparation of compound 2_4, and other related structures as 25, and cyclization of them to their respective cage structures 26.

PAGE 22

13 H^OMs base 25 26 A fourth approach to 18, which was also studied as a part of this research, was the possible intramolecular Diels Alder reaction of 28_ to 18 . A route to 2&_ was envisioned by the well documented 1,428 29 elimination of bromine by zinc in dimethylformamide of 27_, the Diels Alder adduct of p-benzoquinone and 2 , 3-di(bromoethyl)~l,3-butadiene. OX; Br Zn/DMF CIU Br C) 0">x 18 27 28 In order for a monomer like J^ to be polymerizable by a triple 1,4-initiation it is immediately obvious that monomers such as 29_ and 30 , which are steric models for 16_, would have to be subject to a 1,4polymerization. Hence another objective of this research was the synthesis of 5,5,6,6-tetrasubstituted cyclohexadienes like 29 and 30 and the study of their polymerizations. CN CN S^ CN CN o* 29 30 SCH, ch;

PAGE 23

CHAPTER II Polymerization St udies of 4-Substituted--l,2 ,4-triazoline-3,5 -diones A. Copolymer ization of Ethyl Vinyl Ether and Divinyl Ether with 4-Phenyl-l,2,4-triazoline-3,5-dione Structure of the copolymers 4-Phenyl-l,2,4-triazoline-3,5-dione (PhTD) , 2> spontaneously copolymerized with ethyl vinyl ether (EVE) in methylene chloride solution at room temperature and the product was shown to have a 1:1 composition by elemental analysis and nmr analysis. The copolymer was found exclusive of any 2+2 cycloadduct (1,2-diazetidine) , 31a. a: R= -CH-CHH C CH-O-R l J b: R= -CH=CH 2 N N w Ph 31 Cycloadditions of ethyl azobisformate, _3_2, a similar azo dienophile, have been shown to occur through both nitrogens to give 1,2-diazetidines, 13, or through one nitrogen and one carbonyl oxygen to give oxadiazines, 3Jk Therefore, structure 35^, where propagation occurred through one nitrogen and one carbonyl oxygen, and structure 36, where propagation takes place through the nitrogen to nitrogen bond, appeared to be the most likely candidates for the structure of the copolymer. The nmr spectrum (Fig. 1) did not distinguish between the two 14

PAGE 24

15 N~N . C0 2 R 32 r N N R0 2 C C0 2 R 33 RO C-^ . N=jC' OK 34 possibilities since the observed resonance signals were consistent with either structure. The signals were 67.50 (broad, aromatic hydrogens, 5), 66.05 (broad, hydrogen adjacent to two electronegative atoms, 1), 63.90 (broad, methylene hydrogens of ether, A) and 61.20 (broad, methyl hydrogens of ether, 3). N~N\

PAGE 25

16 I V V U :• to •H

PAGE 26

17 37 38, _39_ and 40_ as model compounds in a recent study of the homopolymerization of triazoline diones . A strong 1605 cm. absorb ance was observed in 38 and not in 39 and 40. 0=-O"0ch 3 .^ ), 0^ >o N N N N CH 3 CH 3 CH 3 38 39 40 Neither PhTD nor its precursor 4-phenyl urazole had an infrared absorbance in the 1610 cm. region. This information, along with that obtained from the model compounds, appears as solid evidence for the assignment of 15 as the predominant repeat unit of the copolymer. In contrast to the EVE system, divinyl ether (DVE) and PhTD were observed to form a mixture of copolymer and an adduct at room temperature in methylene chloride. When the reaction was done at 60°C only copolymer was isolated. The adduct from the room temperature reaction was isolated in pure form and was assigned as the 1,2-diazetidine, 3-phenyl-6-vinyloxy-l,3,5triazabicyclo[3.2.0Jhepta-2,4-dione, 31b. The infrared spectrum gave no 1610 cm. absorbance, but gave strong vinyl ether absorbances at 1645 cm." and 1625 cm.~ ". The nmr (Fig. 2) spectrum gave resonance

PAGE 27

18

PAGE 28

19 signals at 67.40 (singlet, aromatic hydrogens, 5), 56.60 (quartet, vinyl hydrogen, 1), 55.90 (triplet, hydrogen next to vinyloxy on ring, 1), 64.50 (multiplet, vinylic and ring methylene hydrogens, 4). The mass spectrum yielded the correct molecular ion and the elemental analysis agreed with the calculated value. On warming an unpurified mixture of polymer and adduct to 60°C, a ring opening polymerization occurred. This was noted by the disappearance of the 65.90 triplet in the nmr spectrum and the formation of a product which gave identical spectral data as the original 60°C copolymer. An elemental analysis of the copolymer was indicative of a 1:1 structure and for such a copolymer three structures were probable. The first two, 41_ and 42, were analogous to the EVE case in which only one double bond is consumed and the third, 4_3, was precedeuted by cyclocopolymerization in which both double bonds are consumed. \ o-L y-Q K Ph 41 9 CH ii CH, 0s — N >o ? CH-CH, N Ph CH, 42 -> r\ — N >0 N h ?;3

PAGE 29

20 On the basis of spectroscopic and chemical evidence, repeat unit 41_ appeared to predominate. First, the absence of upfield resonances in the mar spectrum indicated that there were no methylene units flanked by saturated carbon atoms. Since a requirement for the cyclic structure 43 would be upfield resonances, this structure was eliminated. The resonance signals observed (Fig. 3), 67.48 (broad, aromatic hydrogens, 5), 66.30 (broad, vinylic hydrogen and hydrogen adjacent to two heteroatoms, 2) and 64.20 (broad, methylene and vinyl hydrogens, 4), were consistent with both structures 4_1 and 42. The infrared spectrum of the copolymers, as in the EVE copolymers, showed a strong 1610 cm. band and this was assigned to the -C=Nunit. Also present in the infrared spectrum were bands at 1640 cm. and -1 3? 33 860 cm. due to the vinyl ether chromophore. ' As insurance that the 1610 cm. band was not associated with the aromatic moiety, a copolymer of DVE and 4-methyl-l,2 , 4-triazoline3,5-dione was prepared. This copolymer also exhibited the strong 1610 era. absorbance. The nmr spectrum of this copolymer is given in Fig. 4. Catalytic hydrogenation of the DVE copolymer over palladium on alumina at atmospheric pressure resulted in the absorption of the theoretical amount of hydrogen for a structure like 4l_ or 42_. The resulting material exhibited a new 2770 cm. band due to the saturated carbon hydrogen stretch, and loss of 1640 cm. and 860 cm. bands of the pendant vinyl group in the infrared spectrum. The 1610 cm. band also disappeared. New resonances appeared in the nmr spectrum at 63.90 and 61.20. These signals had the same chemical shifts as the ethyl protons .in the EVE copolymers.

PAGE 30

2 J

PAGE 31

22 **^

PAGE 32

2 3 One discrepancy in the hydrogenation results was the disappearance of the 1610 cm. band in the infrared spectrum. This was thought to be due to an isomerization over the alumina catalyst for the following reasons. The -*C=N-* linkage has been shown to be resistant to 30 catalytic hydrogenation when it appeared in oxadiazine structures like J34. The catalytic hydrogenation of the EVE copolymer was carried out as a control and although no hydrogen was absorbed, the loss of the 1610 cm. band was noted. A plausible explanation is that the catalyst promotes an isomerization from structure 35_ to the structure bonded through both nitrogens, _34. If this were the case, a decrease in the molecular weight of the copolymers should be observed since such a change would require bond breaking and then bond reformation. This was exactly what was observed as a DVE-PhTD copolymer had a molecular weight of 1590 before hydrogenation and 490 afterwards. An attempt to use palladium on carbon as the catalyst only gave a partial hydrogenation. Physical charact er istics of the copol ymer The copolymers of EVE-PhTD and DVE-PhTD were white, highly electrostatic solids which were soluble in most organic polar solvents, Maximum number average molecular weights (M ) were normally in the 1000 to 3000 range and were measured by vapor pressure osmometry (VPO) in acetone solution. The polymeric materials were low melting and both copolymers softened around 100— 110°C. A molecular weight distribution (Mv/M > of 3.36 was obtained for one DVE-PhTD sample from gel permeation chromatography CGPC) . The determination was made in dimethylformamide and a calculation of the

PAGE 33

24 M from' the GPC trace gave a value of 2500 versus 2750 from the VPO. An attempted GPC analysis of an EVE-PhTD copolymer was unsuccessful due to what was believed to be a degradation of the polymer in the highly polar solvent. Spontan eous copolymerizations Since the copolymerization of EVE and PhTD was certainly a spontaneous copolymerization, the literature was reviewed to obtain examples of previous spontaneous copolymerizations. Spontaneous copolymerizations are differentiated in this discussion from other 34 types of photoinitiated spontaneous copolymerizations and Lewis acid 35 catalyzed spontaneous copolymerizations by defining a spontaneous copolymerization as one that occurs when two olefinic monomers are mixed in bulk or in solution at room temperature or lower with no additional initiator involved. All observations of spontaneous copolymerizations reported in the literature have involved an olefinic monomer pair in which one partner was electron rich and the other electron poor. Apparently, the first report of such a copolymerization was disclosed in a Canadian patent authored by Miller and Gilbert. They reported the spontaneous copolymerization of vinylidene cyanide and alkyl vinyl ethers. No mechanistic interpretation of their results appeared. 37 Yang and Gaoni have prepared 1:1 copolymers from the spontaneous reaction of trinitrostyrene, 44_, as the acceptor or electron poor olefin and either 4-vinyl pyridine, 45_, 2-vinyl pyridine or p-dimethylaminostyrene as the donor or electron rich olefin. The authors suggested that the monomers formed an initial donor acceptor complex

PAGE 34

25 copolymer 45 44 which initiated the radical copolymerization of the monomers. Kosower has suggested that the copolymerization is initiated by the formation of a ground state donor acceptor complex which goes to an excited ion pair state which then copolymerizes the surrounding ground state donor acceptor complexes according to the equation shown above. Such a mechanism is designated by Kosower to be a "T-Class Reaction" in which the electron transfer in the complex is brought OQ about by thermal energy. The general equation for this reaction, D*A (QA) r 'D-A(d! a:) r-d>a: D-A proposed by Kosower, includes formation of a ground state complex (D,A) which experiences a thermally induced electron transfer to the excited ion pair form (D., A.) and then can go to products or can disassociate to the separate ion pair excited state. 9 39 Butler and Sharpe ' have reported two other systems which fit the definition of spontaneous copolymerization. One system in which this type reaction occurs is the cyclocopolymerization of maleic

PAGE 35

26 9 anhydride and DVE, arid the other is the cyclocopolymerization of 39 divinyl sulfone and DVE. Both systems are believed to form a donor acceptor complex which then goes to an excited state, couples to form a ciradical and thus initiates the copciymerization of either complexed or uncomplexed comonomers. Mechani sm of EVE and DVE copolymerizations PhTD has been shown to undergo 2+2 cycloadditions with both 30 indene and p-dioxene. The cycloaddition with indene has been shown to involve a dipolar intermediate since this 1,4-dipolar species has been trapped with water. p-Dioxene formed the expected 2+2 adduct plus a lot of discarded polymeric material. In light of these results and in light of the polymer structures, the most plausible propagation mechanism is believed to be the initial formation of a stable 1,4-dipole. This intermediate, in the EVE system, then went directly to copolymer, while in the DVE system it formed the 1 ,2-diazetidine 31b and copolymer. At 60°C, the diazetidine is proposed to open to the initial 1,4-dipole and couple intermolecularly to form the copolymer 41. The difference in behavior between the EVE and DVE systems can be rationalized in terms of the stabilities of the positive centers of the respective 1,4-dipoles. The acid hydrolysis of EVE has been 40 observed to be 350 times faster than the acid hydrolysis of DVE. This difference is due to the stability of the corresponding oxonium ion intermediates, h]_ versus _48. The same positive center stabilization occurs in the two 1,4-dipoles. Therefore it is believed that the more stable 1,4-dipole (EVE) has a more pronounced dipolar character and

PAGE 36

27 O^V 0-" CH 2\CH, 47." 48 links intermolecularly , while the energetically higher DVE dipole closes to the strained 1 ,2-diazetidine. The exact nature of the transition state leading to the 1,4-dipole is not known. Kosower has proposed that 2+2 cycloadditions which are dipolar in nature are "T Class Reactions" and they go through an excited charge transfer complex which then couples to the corresponding dipolar species. This dipole then closes to a four member ed ring. The formation of the vinyl ether-PhTD intermediate 46 by this pathway is shown below. N I ?'n N— NPh -/ ',N~^N \* Ph 46 The other possibility is an electrophilic attack of the electron poor PhTD on the electron rich olefin in which no complex is required to arrive at 46 ? i.e. , R _ / JSsSL O-o N Ph + /CH— R f H 2 N— N', Ph 46

PAGE 37

28 The first observation that is consistent with the postulated 1,4-dipole is the non-cyclic structure of the DVE-PhTD copolymer. A diradical intermediate would have been expected to cyclize. However, cyclization of the 1,4-dipole 46_ would be highly unlikely since vinyl ethers are known to be resistant to anionic attack. Copolyraerizations of the two vinyl ethers with PhTD were found to be insensitive to a free radical inhibitor and a free radical initiator. The free radical initiator azobisisobutyronitrile (AIBN) had no effect on the molecular weight of the. EVE copolymers (Table 1, exp. 11). The copolymer from the DVE case showed some increase in molecular weight, which some random coupling of pendant, vinyl groups could easily explain (Table 2, exp. 3). The known free radical inhibitor, m-dinitrobenzene, had no effect on the copolymer ization of DVE (Table 2, exp. 6). An attempt to free radically copolymerize DVE and PhTD at -45°C by photolytic decomposition of benzoyl peroxide only resulted in a product identical to the ambient copolymerizations . Since the conversion was extremely low, the product was probably the result of a slow thermal reaction, because at the same temperature the same product was obtained without benzoyl peroxide. In an attempt to exclude moisture from the system, a copolymerization of DVE and PhTD was effected under more rigorous conditions than the normal trials. It was felt that since water would terminate the dipolar step-growing chain that the elimination of moisture would lead to a higher molecular weight copolymer. The dry conditions included flame drying of glassware, predrying of monomers and transfering monomers and solvents in an inert and dry atmosphere. Although

PAGE 38

29 w

PAGE 39

Is*

PAGE 40

31 w

PAGE 41

32 Cl)

PAGE 42

33 a higher molecular weight material was obtained than, in the normal trials, a control in which the glassware was not treated yielded even higher molecular weights (Table 2, exp. 7 vs. exp. 5). 41 Szwarc has discussed in great detail the effect of trace amounts of water on ionic polymerizations and the conditions needed to conduct polymerizations in the absence of water and other impurities. Since the purification procedures needed for such experiments required special techniques and equipment, this approach was abandoned. Surprisingly, the EVE-PhTD copolymerization conducted at 60°C resulted in a lower molecular weight product than in the room temperature trials. The 1610 cm. band in the infrared spectrum of the copolymer was absent, although the nmr spectrum was the same. The elemental analysis remained consistent with a 1:1 copolymer. The room temperature copolymerization was repeated for a 24 hour period and a molecular weight of 430 was obtained compared to 2440 for a thirty minute polymerization time. The 1610 cm. infrared band was absent in the product from the 24 hour run. A study of molecular weight versus time was conducted for the room temperature copolymerization and the results are shown in Fig. 5. A decrease in intensity of the 1610 cm. band paralleled the decrease in molecular weight. Table 1 gives the molecular weight versus time in tabular form. Copolymerizations conducted at 60°C for extended times showed a rebuilding of the chain length (Table 1, exps. 15, 16 and 17). These results can easily be accommodated by the proposed copolymerization mechanism. The decrease in molecular weight is believed to result from a depolymerization back to the 1,4-dipole structure and then recombination through both nitrogens to give structure 36 ,

PAGE 43

34 cnj CM

PAGE 44

35 possibly a more stable structure. The DVE copolymer once formed was observed to be thermally stable at 60°C as noted by no decrease in molecular weight or decrease in the intensity of the 1610 cm. absorbance. Since tho activation energy to reformation of the vinyloxy 1,4dipole would be expected to be higher than the ethyloxy because of the difference in stability of the positive center, this result is also consistent with tbe polymerization mechanism. It is generally thought that dipolar reactions should show pronounced solvent effects. The results of a solvent study of the reaction rate are shown in Table 3. This study was conducted by observing the disappearance of the band in the visible spectrum of the PhTD. No pronounced rate differences were observed in going from the fairly non-polar solvent benzene to the strongly polar solvents dimethylformamide and acetonitrile. There was a distinctive rate difference between EVE and DVE. This was probably another manifestation of the difference. in the stability of the positive center of the dipole. 4 2 Gompper has recently reviewed cycloaddition reactions involving polar intermediates. He cites two cases in which significant solvent effects may not accompany such reactions. The first case involves reactants that are highly polar and thus experience significant solvation effects to effectively negate the solvation of the intermediate. The second case involves a system where the energies of activation of the first step and the second step are nearly the same and a change in solvent changes the rate determining step, but not necessarily the overall reaction rate. Since both monomers are highly polar molecules, it is reasonable that they could experience enough ground state solvation to effectively cause the solvation of the intermediate to be undetectable.

PAGE 45

36 One criterion which can conclusively demonstrate the presence of a dipolar intermediate is the interception of this intermediate before 42 cycloproduct formation. When EVE and PhTD were reacted at room temperature in acetone 3-oxa-2 ,2~dimethyl-4-ethoxy-8-phenyl-l,6 ,8triazabicyclo[4.3.0]-non ^ />: X CH. N Ph of the intercepted dipole did not close to the six membered adduct but proceeded to link intermolecularly with other similar segments or with other 1,4-dipoles to form the copolymer containing about 12% acetone.

PAGE 46

37 TAELE 3. FIRST ORDER RATE CONSTANTS IN PhTD AT 25°C A.

PAGE 47

3?

PAGE 48

39 42.43,44 In previous studies ' of the 1,4-dipoles, many different reactive dipolarophiles have been utilized to intercept the dipolar intermediates s i.e., isocyanates , acetylene dicarboxylate esters and ketenes, among many others. However, app-rrertly only one case has been reported of a ketone performing this function and this involved the reaction of perhaloacetones with cyanaraides to form 1,3,5-oxadiazines. CK CF V K-C=N + 9=0 c < CF 3 CH 3 . J N-C-N i C < ' CH 3 CF N / CH 3 N A CH C1I J possible intermediate CH„ CH„ 3 + / 3 Ch' N CH 3 CF 3 CCF 3 To investigate the scope of this novel interception reaction, both the vinyl ether and the ketone solvent were varied. When isobutyl vinyl ether was substituted for ethyl vinyl ether 3-oxa-2,2-dimethyl4-isobutoxy~8-phenyl-l,6 ,8-triazabicyclo[4 . 3.0]nona-7 ,9-dione , 50_, was formed in 47% yield. The infrared spectrum was practically identical to that of 49^ with only minor differences noted in the C-H stretching frequencies and in the fingerprint region of the spectrum. The nmr spectrum was similar to ^9 except a doublet for the methyl groups of the isobutyl group was present at 50.95 (6), and the multiplet due

PAGE 49

40 to the methylene protons was less complex because of the isobutyl group . 2 3'2 0CH o CH Q Wl-*-H 2 | I j CH— v CR ^ CH— 0. CH— o< N >o o-A n >o < > I'll 'N' Ph 50 51 52 Changing the ketone solvent from acetone to cyclohexanone resulted in formation of 3-oxa-2— spirocyclohexyl-4-ethoxy-8-phenyl1,6 , 8-triazabicyclo[4. 3.0]nona-7 ,9-dione ? 51 in 12% yield. Apparently the low yield resulted from the more complicated procedure for product isolation. The infrared spectrum appeared practically identical to 49 and 50. The nmr spectrum differed from that of 49_ in that the nonequivalent methyl resonances at 61.70 and 61.85 were, replaced by a broad multiplet resonance from 61.50-62.80 (10) from the cyclohexyl protons . Divinyl ether, PhTD and acetone resulted in a small amount of the tetrahydrooxadiazine 52 and a trace of 1,2-diazetidine 31b . Both were identified by nmr with the oxadiazine spectrum resembling 49 , 50 and 51, while the 1,2-diazetidine resonances were identical to those of the room temperature product of DVE-PhTD in methylene chloride 31b . The mass spectral fragmentation patterns offered strong corroborative evidence for the proposed new 1,3,4— tetrahydrooxadiazine ring structures. The fragmentation patterns were very similar to known

PAGE 50

4] 45 cyclic acetal fragmentations. They were different in that the molecular ion appeared. This could be due to the unique structure in which one ether linkage was inside the ring and the other was outside. Scheme I shows the fragmentation pattern for 49. The molecular ion m/e 305 (1%) is believed to fragment by two pathways, a and b. Scheme I 0CH 2 CH cf h ~"V CH 3 b CH-0 CH^CH 2 CH J \ *™™ ?V CH 3 fl N N __ N \N^ 0-/ x >0 3 3 ^ ^ =0 m/e247 Ph N N * base peak m/e260 Ph Ph m/e3 ° 5 (m+) + -ch^ch x y CH CH ' N-< -CO ) \ -H, N N v o-O^~ °~-\^° " — ° V-'° Ph Ph Ph m/el90 m/e218 m/e219 Pathway "a" involves loss of acetone to form m/e 247 , the base ion. This is followed by the loss of ethylene to m/e 219 (8%) which then appears to rearrange and lose a hydrogen atom to m/e 218 (22%) . Ion m/e 190 (59%) subsequently follows by loss of carbon monoxide. Pathway "b" involves loss of the ethoxy radical to form ion m/e 260 46 47 (7%), a general cracking course for both acetals and glucosides. Comparison of the fragmentation of 50 and 51 (Schemes II and III

PAGE 51

42 Scheme II CH-0 OCfi CH(CH ) + / \ CH > 9 rH CH=OCH CH(CH ) W CH 3 ^J \ 2 ' / XCH 3 * \ 2 0^L>0 -OCH 2 CH(CH 3 ) 2 QC / V Q , / \ N J N Ph Ph . Ph m/e260 m/e333 (M+) m/e275 V-CH|=CH(CH ) \ § H CH, C ^2 H CH " N • N Ph Ph Ph m/el90 m/e218 m/e219 base peak Scheme III OCH2CH3 + N-N -0CH„CH, / N ~~A. ^— N' Ph Ph m/e300 m/e345 (M+) m/e247 base peaic o N Ph -CH~CH 2 CH, / CE ° OH C \ 2 .« H r^H \ C0 N— N" ~ H C . H 2 K •* / \ * \ m/el90 m /e218 *j Ph m/e219

PAGE 52

43 respectively) with that of 49_ shows similar ions resulting from the same double fragmentation pathway. From these results (summarized in Table 4) it appears that the reactivity of the 1,4-dipole is quite sensitive to stabilization of its positive center. The high yields of oxadiazine when the carbonium ion stabilizing substituents, ethoxy and isobutoxy, are present and the low yield with vinyloxy are believed to mean that the intermediate has more pronounced dipolar character when its positive center is stabilized and hence can add across the weak dipolarophilic alkyl ketones. This is the same reasoning used to explain the earlier copolymerization results. In agreement with the above observations 30 is the PhTD-indene reaction in which no oxadiazine was reported even though the reaction was performed in acetone. TABLE 4. SUMMARY OF INTERCEPTION REACTION RESULTS Vinyl Ether Ketone % Yield M.P. C1I =CH-0-CH CHAcetone 42% 149-151°C CH =CH~OCH CHCyclohexanone 12% a 170-171°C CH I CH =CH-0-CH„-C-CH Acetone 47% 125-126°C b CH =CH-0-CH=CH 9 Acetone trace (a) Yield lower possibly because of difficulty in work up. (b) Identified from nmr. Also some 1,2-diazetidine formed. By employing this unique property of these 1,4-dipoles, it was felt that information on the degradation of the EVE-PhTD copolymer could be obtained. When a high molecular weight sample of this

PAGE 53

44 copolymer was refluxed in acetone, the usual decrease in molecular weight was observed along with a trace amount of oxadiazine 49. This was believed to result from degradation back to the initial 1,4-dipole which in turn was trapped by the acetone. This is interpreted to mean that, at least in part, the degradation is a reverse reaction of the original polymer formation. Soluble salts are generally known to exhibit significant effects in either anionic or cationic polymerizations. It was felt that the ions of a soluble salt would effectively "tie up" some of the "living ends" of the propagating dipole and prevent their intermolecular coupling and hence lower the molecular weight. Mien the EVE-PhTD copolymerization was effected in tetrahydrofuran solution in the presence of 10 mole % of sodium tetraphenylboron, a significant change in the molecular weight was observed. A control in tetrahydrofuran yielded an average molecular weight of. 2040 versus 940 for the sample containing the salt. Another mechanistic pathway which merits consideration is that of a ring opening polymerization resulting from attack of the zwitterionic intermediate on an unopened 1,2-diazetidine. Although the data do not allow this mechanism to be disregarded, especially in the DVE case, the observation of molecular weight increase with time for both the DVE and EVE cases is not consistent with such a propagation mechanism. This evidence is particularly persuading for the EVE-PhTD copolymerizations because of two observations. The first observation resulted from an experiment conducted in an nmr tube. This experiment showed that when the reactants were mixed and inserted directly into tbe nmr cavity only copolymer was observed. The second observation was that

PAGE 54

45 even though all the PhTD was consumed after 10 minutes in the PhTDEVE copolymerization, the molecular weight increased over a 0.5 hour time period (Fig5). Since no adduct was present as indicated by the first experiment, the molecular weight growth is attributed to dipolar 48 coupling. Wilson and Beaman have recently observed a system in which the molecular weight increased after an addition polymerization was complete and attributed the phenomenon to a coupling of residual polymeric dipoles. Another polymerization in which some dipolar coupling was postulated was the catalytically initiated polymerization of 1,1,3 ,3-tetra49 methyl-l,3-disilacyclobutane, 53 . u .-Si — I CH, Si-CH CH_ 3 I CH 3 5_3 The vinyl ether-PhTD copolymerizations are believed to be the first reported cases of a dipolar coupling being the sole propagation mechanism. Mechanism of termination In all of the copolymerizations the highest molecular weights obtained were only in the vicinity of 3000 (Tables 1 and 2). These low molecular weights are thought to be a result of facile termination reactions. As was stated -earlier, ionic polymerizations are readily subject to termination reactions by impurities such as water. At least two other termination reactions could occur. The first would be an intramolecular dipolar coupling to a macrocyclic structure and the

PAGE 55

46 second is a type of disproportionation to an inactive species as shown below. Another possible consideration is that the dipoles are ~n— n n y— N "*) = \ S=0 *" CHUCH 0-V T y~{ xr UN +"N— N H -i ^CH— CH + 6 P Ph R Ph so stabilized to result in a "living" structure. Unfortunately no experimental evidence was obtained supporting any of the possible termination reactions. B. Copolymerization of 4--Pheny l--l,2 > 4-triazo li ne~3,5--dione with. Other Monomers Vinyl acetat e and divinyl carbonate To broaden the scope of the copolymerization and reaction characteristics of PhTD, its reactivity was investigated with several other olefinic systems. Vinyl acetate (VAC) and Divinyl carbonate (DVC) were chosen for investigation because these monomers were expected to be somewhat less reactive than the vinyl ethers. VAC was observed to react with PhTD at room temperature, but at a considerably slower rate than the vinyl ethers. The infrared spectrum of the product exhibited a medium intensity 1610 cm. band. The nmr spectrum gave broao 1 resonances at 57.48, 64.32 and 6?. 16. Superimposed over these resonances were sharp singlets. A reaction conducted at 60°C in a sealed tube yielded as the major product an adduct which was assigned structure 55, l-(formylmechyl)-2-acetyl-l,2 ,4-triazoline-3,5-

PAGE 56

47
PAGE 57

48 dione. This compound apparently arose from an internal trap of the intermediate 1,4-dipole 54. + S\ CtC'0/0 c-h n ch 2 p x:h 3 oL c-ch 3 N — N" *~ \ — N < )• 0=^ >o o-V J~o 'N Ph Ph 54 • 55 The infrared spectrum of 55 showed two weak bands characteristic of an aldehyde carbon hydrogen stretch at 2860 cm. and 2750 cm. A double carbonyl absorbance at 1800 cm. and 1730 cm. was also characteristic of the urazole type structure. The nmc spectrum (Fig. 7) gave resonance signals at 69.56 (singlet, aldehyde hydrogen, 1), 67.50 (singlet, aromatic hydrogens, 5), ^4.80 (singlet, methylene hydrogens, 2) and 62.60 (singlet, methyl hydrogens, 3). The mass spectrum yielded the correct parent peak at m/e 261 and the elemental analysis agreed with the 1:1 structure. The broad nmr resonances and the 1610 cm. infrared band were probably indicative of the formation of some copolymer in the room temperature reaction. The small amount cf polymeric material is be. lieved to be indicative of the low activation energy of the intramolecular s:'x menbered transition state rearrangement. An attempt to trap the initial dipole before the intramolecular reaction occurred was made utilizing a large excess of phenyl isocyanate as the dipolarophile. Only 5_5_ was isolated. The reaction was also performed in acetone so that the initial dipole could be trapped

PAGE 58

49 > ^ i

PAGE 59

50 to form an oxadiazine as was accomplished in the vinyl ethers. The majority of the reaction was 55. A few milligrams of material were isolated which gave an nmr spectrum with resonance signals at 66.30 (mul— tiplet) , 63.75 (doublet) and 61.72 (singlet). The spectrum was complicated by the presence of 55 . The above resonances appeared in the ratio of 1:2:6. This could be evidence for the formation of a small amount of the oxadiazine 56. 9, 0-CCH3 CH. X N — N N — N Ph 56 DVC was found to react slowly at room temperature and at 60°C to give a material shown by elemental analysis to be a 2:1 structure. A strong 1610 cm. band was observed in the infrared spectrum and the nmr spectrum gave broad resonances at 67.38 (singlet, broad, 6) and 65.31-63.31 (multiplet, broad, 1). A molecular weight of 1220 was obtained for the 60° C polymerization. No observations were indicative of the occurrence of a double internal trapping reaction analogous to the vinyl acetate reaction. Divinyl s ulfo ne and_ acr ylonitrile The normally electron poor olefins divinyl sulfone (DVS0_) and acrylonitrile CAN) were chosen for investigation to see if they would act as electron donors with PhTD. CVS0„ appeared to give some reaction since more solid was obtained

PAGE 60

51 in an attempted copolymerization at 60°C than was obtained with a control of PhTD. No sulfone absorbances were noted in the infrared spectrum and an elemental analysis only yielded a trace of sulfur. AN showed no indication of reaction at room temperature or at 60°C for six days. At 60°C, with a free radical initiator present, some product appeared to result. An analysis of the infrared spectrum showed a new medium intensity 1610 cm. band. An elemental analysis yielded a higher nitrogen content than would result from a reaction only involving PhTD. No structure assignments were feasible. N -vinyl carbazol e N-vinyl carbazole (NVC) was observed to spontaneously copolymerize at 25°C to yield an 86% yield of a 1:1 copolymer. The composition was established by elemental analysis. Only a weak-medium 1610 cm. absorbance was observed in the infrared spectrum. The nmr spectrum yielded two large broad resonances centered at 68.50 and 55.30. Because of the weak 1610 cm." absorbance the polymer structure was thought to be 57. —J n Insolubility of the polymer in acetone precluded the usual vapor pressure osmometer molecular weight determination. However, calculation of the number average molecular weight from gel permeation chromatog-

PAGE 61

32 raphy, calibrated with polystyrene, gave a value of 21,000. The weight average was calculated to be 54,000 and the molecular weight distribution (M /M ) was 2.57. In making the calculations a very w n dangerous assumption was necessary. It was assumed that polystyrene and the copolymer had similar coil dimensions in the solvent used for the determination. Although this assumption appeared to be valid in the DVE-PhTD copolymer, it was not necessarily valid in this case. The molecular weight obtained in this system is significantly higher than in the vinyl ether copolymers. No reasons are apparent for the change in structure and the change in molecular weight of the NVC system. When the polymerization was conducted in acetone, a similar polymeric structure was obtained. Only a minute amount, if any, of the corresponding oxadiazine was observed. An nmr spectrum from a small amount of apparently noru-polymeric material showed multiplets at 64.50 from methylene hydrogens and 62.20 from methyl hydrogens. Not enough material was isolated to identify and characterize this product. The failure of acetone to trap the probable intermediate dipole is probably due to the large steric effect of the vinyl carbazole moiety. Stille and Aoki have initiated the homopolymerization of electron donors by addition of catalytic amounts of strong electron acceptors. The homopolymerizations are proposed to be initiated by an excited ionic s'-ate of a charge transfer complex, Since NVC is known to readily homopolymerize, it was thought that the addition of a small amount of PhTD to a solution of NVC could possibly trigger a cationic homopolymerization of the NVC in which the initiation would

PAGE 62

53 be effected by the positive end of the dipole. An attempted polymerization was unsuccessful. £. R eactions and Attempted Horaopolymerizations of 4-Phen yl-l ,2,4triazoline-3 ,5-dlone 4-substituted-l,2 ,4-triazoline-3,5-diones have the potential to yield polymers possessing a nitrogen backbone if an initiation could be effected through the nitrogen to nitrogen double bond. This promise made the investigation of the behavior of the triazoline diones in the presence of radical and ionic initiating species an attractive proposal. PhTD has been described as decomposing instantly in basic solution, while in the presence of acid, water or alcohol the rate of decomposition was noted to be slower. Even in the presence of light or in solution at room temperature some decomposition was reported. No one has studied the decomposition products and their mechanisms of formation. The thermal decomposition of PhTD at 60°C in a scaled tube was studied to determine if there was any appreciable decomposition that could compete with the copolymerizations . During the course of the reaction the color remained red and a few milligrams of a white crystalline solid formed in the bottom of the tube. Precipitation of the red solution yielded a small amount of tan-white solid 59 . The white crystalline solid did not melt when the temperature was raised to 300°C. The infrared spectrum gave no saturated carbonhydrogen stretching absorbances and gave a double carbonyl at 1785 cm. and 1755 cm. The mass spectrum yielded a parent peak at m/e 322

PAGE 63

54 and a base peak at m/e 119 (phenyl isocyanate ion) . Structure 58 , 3,7-diphenyl~l,5--diazabicyclo[3. 3.0]octa~2 ,4,6 ,8-tetraone, was assigned from this data. An elemental analysis perfectly agreed with the calculated value. n ii Ph-N N-Ph i ii 58 52 Two reports of 58 were found in the literature. Snyder reported the formation of a bright orange solid, melting point 203-204°C, during a refluxing reaction of PhTD. In this case PhTD was generated by oxidation with t-butyl hypochlorite in acetone. The only structure proof presented was infrared data which included a double carbonyl 53 and an aromatic absorbance. Koch and Fahr reported the formation of 58_ in a thermal reaction of PhTD in an apolar solvent. No structure proof or physical characteristics were presented. The tan-white solid _59_ isolated by precipitation into hexane had 3500 cm. and 1715 cm. absorbances in the infrared spectrum. The nmr spectrum gave broad resonances at 67.50 (broad multiplet, 6) and 64.48 (broad multiplet, 1). The number average molecular weight from vapor pressure osmometry was found to be 600. The elemental analysis did not correspond to any regular structure resulting from a homopolymerization of PhTD. When PhTD was heated in a sealed tube in methylene chloride solution in the presence, of azobis.isobutyronitrile, results identical to reaction without the free radical initiator were obtained. An

PAGE 64

55 attempt to initiate a free radical homopolymerization of PhTD by photolysis of benzoyl peroxide at -45°C only resulted in a small amount of the oligomeric PhTD decomposition product 59. In attempting to explain the mechanistic pathway for the thermal decomposition of PhTD to 59_, the first reaction is probably the formation of phenyl isocyanate. Phenyl isocyanate could then in turn heat O.rVo ~~~ > Ph-N=C=0 NT ~ N 2 Ph -co react with water to form aniline. When a catalytic amount of aniline H -CO Ph-N-C-0 + H 2 -> [Ph-N-C-0-H] =»PhNH, was added to a methylene chloride solution of PhTD, some of the oligomeric decomposition product 5_9_ resulted. Another related experiment was to see what products were formed in the decomposition of PhTD by water, since PhTD had already been 51 shown to readily decompose in water. When PhTD, in dioxane solution, was added to water a vigorous reaction insued and a large amount of oligomeric product 59_ was obtained. A small amount of N,N'-diphenyl urea was also obtained. One of the products from the reaction is ' most assuredly phenyl isocyanate which then goes to aniline and then reacts with more phenyl isocyanate to yield the diphenyl urea. Since aniline served as a catalyst for formation of the oligomeric product 59 , an investigation using other nucleophilic species was initiated in hopes of effecting the formation of high polymer. Triethylamine was used as the initiator and a similar product 59

PAGE 65

56 was obtained. Surprisingly approximately 10% of 58^ was isolated. The strong nucleophilic reagent, sodium cyanide in dimethylformamide was then used as the initiator and a large yield 70-80 per cent of the tetraone 58 was obtained. A small amount of 5_9^ was also obtained, The rationalization of the formation of 5_8_ from attack of a nucleophile on PhTD presents an interesting mechanistic problem that was not covered in the scope of this research. However, the following explanation is put forth as a possible mechanistic pathway of the unusual reaction. 54 Kealy has observed the formation of 61_ from the decomposition of diazoquinone 60 . He did not propose a mechanism for the formation of J51_, but only referred to earlier work on the decomposition of azo compounds by radical pathways. For example, Leffler and Bond have studied the radical decomposition of dibenzoyl diimide 62_ where ^3 is one radical intermediate. PhC-N=N-CPh 62 \-: ii II m 1 1 2 PhC 63 60 §1 For the diazoquinone, a probable diradical intermediate would be 64_ which could couple with an intact molecule of diazoquinone j50 to yield 61 . If such a diradical. intermediate 65_ was involved in the formation of the tetraone 58 from a nucleophilic catalyzed reaction of PhTD

PAGE 66

57 r 60 61 64 an unusual carbenoid mechanism could be involved as shown below. No proof has been gathered in support of this mechanism, although in the studies conducted on the radical decomposition of 62_ much higher rates of decomposition were observed in strongly nucleophilic solvents like aniline. The reason for this could be a nucleophilic catalyzed reaction as was discussed for the formation of 53. Exp. No. 1 2 3 4 5 6 7 TABLE 6. SUMMARY OF CATALYZED PhTD REACTIONS Conditions Products 90°C, vacuum Most electron poor comonomers CH CI , 60°C, 70 hrs., sealed tube CH CI 60°C, 24 hrs., sealed tube water, dioxane, 25 °C, 1 hr. aniline, CH CI , 25°C triethyl amine, CH CI 25°C, 1 hr. sodium cyanide, dimethylformamide 2,5 hrs., 25 °C 59 (M = 1000) n 59 (small amounts) 59 (27%), 58 (1%) 59 (10.4%), 58 (trace) 59 (61.5%, diphenyl urea, (7.8%) 59 (22.0%) (M = 470) 59 (24.5%), 53 (9.5%) 59 (small amount) 58 (approximately 80.0%) A summary of all the reactions and decompositions of PhTD is presented in Table 6. While this research' was being conducted, Stickler and Pirkle" 1 reported the first synthesis of a nitrogen backboned polymer. Their 12

PAGE 67

38 N~N Ph N n Ph A N Ph rearrangement >„^° 65 53 success resulted from a visible light irradiation of 4-n-butyl-l,2 ,4triazoline-3,5-dione. D. Diels A lder Polymers Synthesis of 4 , 4 ' (4 , 4 ' -dipheny Methylene) -bis-1 , 2 , 4-tr iazoline-3 , 5dione Since the diisccyanate 66^ 4 ,4 ' -dipheny lmethane diisocyanate 5 was readily available from commercial sources, the bis triazoline dione selected as a target for synthesis was _69_, 4 ,4 '-(4,4'-diphenylmethylene)bis-l,2,4-triazoline-3,5-dione . The synthesis of the diurethane precursor _67_ was accomplished in a near quantitative yield by the addition of two moles of ethyl carbazate to 66^. The infrared .spectrum yielded strong N-H stretches at 3330 cm. and 3305 cm. . Strong carbonyl absorbances vere observed at 1735 cm. and 1685 cm. The ninr spectrum gave resonances at 58.77 (singlet, hydrogens on nitrogen, 2), 57.91 (singlet, hydrogens on nitrogen, 2), 57.20 (A ? B., quartet, aromatic hydrogens, 8), 54.05 (quartet, methylene hydrogens, 4),

PAGE 68

59 63.79 (singlet, methylene hydrogens, 2) and 51.19 (triplet, methyl hydrogens, 6.). The product gave the correct elemental analysis. CI1,. -
PAGE 69

60 CH, II 69 -;ycH 3 A CH, ->CH trum which showed resonance signals at 67.33 (multiplet, broad, aromatic hydrogens, 8), 64.00 (broad singlet, allylic next to nitrogen and benzylic hydrogens, 10) and 61.75 (broad singlet, methyl allylic hydrogens, 12). Diels Alder polymerization o_f styrene and 69 Cookson and coworkers have investigated the Diels Alder reactions of triazoline diones and found that PhTD spontaneously reacted with 56 styrene to yield the double Diels Alder adduct 71 . Maleic anhydride and ethyl azobisformate have been shown to react with styrene in a Diels Alder fashion, but the final products in both cases were 7_2 and 73. These products resulted from an ene reaction after the first Diels Alder reaction. Cookson's results meant that styrene, potentially, would be an attractive bis diene to investigate with 69. When styrene was reacted with 6j^ at room temperature in dimethylformami.de solution, the deep red initial color faded to a much lighter red after two hours. After seven and one half hours, the red color, characteristic of unreacted 69^ persisted. The solution was divided and the first half was precipitated into ether to yield a tannish, highly electrostatic powder. The second half was in turn divided into two portions and a discharge of the red color was noted after a few minutes. Precipitation into ether yielded an identical polymer (in-

PAGE 70

61 -C0 2 CH 2 CH -C0 2 CH 2 CH 3 NX .N-C0 2 CH 2 CH 3 C0 2 CH 2 CH 3 73 Ph-N \' / N \x Zi ov \ ph

PAGE 71

62 frared) as the portion precipitated while still red. The last portion was heated to reflux and immediately it began to darken. It was precipitated into ether and a much darker solid resulted. The repeat structure of the polymer was assigned to 74, which results from a Diels Alder adduct which rearomatizes via an ene reaction as 72_ and 73 . This is contrary to what was expected a priori. The assignment was made from the infrared and nmr data and comparison to the model compound 75 . When PhTD and styrene were reacted in methylene chloride at room temperature _7_5 was formed rather than the reported Diels Alder adduct 71 . The infrared spectrum gave an N-H stretch at 3280 cm. and the usual double carbonyls at 1765 cm. and 1720 cm. . The nmr spectrum (Fig. 8) gave resonance signals at 68.38 (doublet, hydrogen on nitrogen, 1) , 67.35 and 67.38 (doublet and multiplet respectively, aromatic hydrogens, 4), 65.70 (triplet, benzyl hydrogen, adjacent to nitrogen, 1) , and 64.22 (multiplet, methylene hydrogens, 2). The elemental analysis agreed with the 2:1 structure. The polymer gave the double carbonyl in the infrared spectrum at 1780 cm. and 1715 cm. . The N-H stretch was very weak. The nmr spectrum (Fig. 9) showed resonances at 68.40 (doublet, broad, hydrogen on nitrogen, 1), 67.37 (singlet, broad, aromatic hydrogens, 12), 65.67 (singlet, broad, benzyl hydrogens adjacent to heteroatom, 1) and 64.50-53.80 (muitiplet, broad, two sets of methylene hydrogens, 4). The polymer was roluble in both dimethylformamide and dimethylsulf oxide. The thermal decomposition was recorded using a Differential Scanning Calorimeter and. was found to start at 307 °C. An intrinsic viscosity determined in dimethylformamide at 28°C was 0.12. Calculation

PAGE 72

63

PAGE 73

64 1°

PAGE 74

65 from gel permeation chromatography showed a molecular weight distribution of 3.34 with the weight average molecular weight, M = 36,000. These values were calculated from a calibration with a polystyrene standard, and again the assumption is made that the coil sizes are similar for the two polymers. An attempted polymerization of 69_ using sodium cyanide in dimethylformamide yielded a light brown polymeric material. The synthesis of a polymer with structure lh_ was the object of this experiment. The infrared spectrum of this material was not similar to the monomeric tetraone 58^ so apparently the desired decomposition and coupling reaction did not take place. 76

PAGE 75

CHAPTER III Triple Strand Polymer Model Compound Studies A. Attempted Synthesis of T etracyclo [ 4.4.0.1 ' .1 ' ] Dodecane and Related Systems Synthetic schemes The synthetic pathway for the attempted synthesis of the cage structure 1_8_ is shown below in Scheme IV. SCHEME IV [J !) + 1 -* f T 1 «? ill z o l ' l 77a, b 1?^.^ ?4 R=a= -0CCH R=b= -H (1) catalytic hydrogenation (2) MsCl 24 base reduction 18 — >. ^. — Scheme V is a proposed synthetic pathway to 25_ which is the precursor to 26, a simplified cage structure related to 18. fib

PAGE 76

6 7 CH„OR or-c o 79a,b 89 R=a= -OCCH R=b= -H 2 5 base SCHEME V

PAGE 77

63 (CH C0CH 2 ) CHCK (CH^OCCHp GH_ /^XIILBr . /--^^CH o 0CCH, 3 /^rf 2 / Ti" 2 3 I) >79a CH 3 CN 85 86 87 59 butadiene sulfone, 8_2_, was prepared by the method of Frank and Seven 29 in 90% yield. This was then brominated with N-bronosuccinimide in 38% yield to 83_. Treatment of this dibromide with silver acetate in acetonitrile resulted in a 73% yield (after recrystallization) of the diacetoxy sulfone 84_. The elemental analysis of this compound agreed with the calculated and the infrared spectrum showed a strong carbonyl absorbance at 1720 cm. for the ester group. The nmr spectrum yielded resonances consistent with the structure and they appeared at 64.75 (singlet, broadened, allylic hydrogens adjacent to acetoxy, 4), 63.86 (singlet, broadened, allylic hydrogens adjacent to sulfone, 4), and 62.08 (singlet, methyl protons, 6). Pyrolysis of 84_ was accomplished smoothly at 200°C and 0.1 mm pressure in 56.6% yield using a Hoskins furnace as the external heat supply. The white solid diene was purified by recrystallization and CO CO yielded the reported melting point. Saponification to 77b was accomplished in 90% yield. By using the same general procedure as used in the preparation of 84 , the sulfone precursor, 87_, to the acetoxy methyl diene 79a was prepared in 74% yield. The bromcmethyl sulfone 86_ was prepared by the method of Krug and Yen by bromination of isoprene sulfone 85_ with N-bromosuccinimide. when 86 was reacted with silver acetate in

PAGE 78

69 acetonitrile 87_ was formed as a yellow-brown oil.. It showed a 1735 cm. ester carbonyl in the infrared spectrum and yielded the correct elemental analysis. The nmr spectrum exhibited resonance signals at 66.07 (singlet, broad, vinylic hydrogen, 1), 64.69 (singlet, broad, allylic hydrogen next to acetoxy, 2), 63.81 (singlet, broad, allylic hydrogen next to sulfone, 4) and 62.10 (singlet, methyl hydrogens, 3). Pyrolysis of this oil was accomplished at 200°C at 0.5 mm. and an 84% yield of 79a was obtained. This was purified by distillation and the infrared characteristics were identical to those reported by Bailey and coworkers who had prepared 79a from the pyrolysis of 88 . 9 9 CH COCH CH CHCH 0CCHCH OpCH 6 J A ttempted Diels Alde r rea ctions with p-benzoquinone Mien the diacetoxymethyl diene 77a and the dihydroxymethyl diene 77b were reacted with p-benzoqulnone, j39_, the normal Diels Alder adducts were not isolated. Reaction of 77a with 89^ in acetic anhydride resulted in the formation of the dehydrogenated adduct 90_. The infrared spectrum of this reddish brown solid exhibited carbonyl absorbances at 1725 cm. (ester) and 1655 cm. (quinone) . The nmr spectrum yielded resonances at 66.75 (singlet, quinodial hydrogens, 2), 64.78 (singlet, allylic hydrogens adjacent to acetoxy, 4), 63.23 (singlet, doubly allylic hydrogens, 4) and 62.12 (singlet, methyl hydrogens, 6). A correct elemental analysis was obtained. The same reaction carried out in benzene yielded a crude oil possessing the same nmr resonances as 90_ with

PAGE 79

70 additional resonances at 66.77, 66.75, 64.64 and .52.43. The 53.23 resonance was broadened considerably. This was apparently a mixture of unreacted quinone (66.77), _90. an d the desired Diels Alder adduct 78a . On addition of ethanol to the oil 90_ was formed as a precipitate and no indication of 78a was found in a spectroscopic analysis. The reaction of 77a and 89_ was then performed in refluxing chloroform and the progress of the reaction was followed by nmr spectroscopy. Disappearance of resonances attributable to starting quinone and diene was observed and the appearance of signals at 66.68 (singlet, quinodial hydrogens, 2), 54.65 (singlet, allylic hydrogens adjacent to acetoxy, 4), 63.27 (multiplet, broad, bridgehead hydrogens, 2) and 62.44 (multiplet, broad, allylic hydrogens, 4) was noted. After 135 hours a conversion of 80% was calculated from the nmr spectrum. 'Removal of the chloroform yielded a yellow oil. This was chromatographed on silica gel and a white solid resulted that showed a strong 3400 cm. band and a disappearance of the 1650 cm. in the infrared spectrum. This indicated that 78a had rearranged to the hydroquinone derivative 91. The nmr spectrum gave resonances at 56.64 (singlet, aromatic hydrogens, 2), 54.48 (singlet, allylic hydrogens adjacent to acetoxy, 4), 63.47 (singlet, doubly allylic hydrogens, 4) and 62.88 (broad, hydroxyl hydrogens) .

PAGE 80

71 The reaction of the dihydroxy diene 77b with 89_ failed to produce the desired Diels Alder adduct as an isolable material also. In refluxing chloroform a brownish solid formed whose nmr spectrum gave no resonances that could be assigned to a Diels Alder adduct. When the reaction was performed in tetrahydrofuran, a brownishyellow oil was obtained which was initially chloroform soluble, but precipitated within a short time as a white solid. The absence of a quinone carbonyl in the infrared spectrum and the absence of bridgehead hydrogen resonances in the nmr spectrum was indicative that the desired Diels Alder adduct 77b was not present. The presence of a strong 1710 cm. absorbance in the infrared spectrum quite possibly may be due to some double Diels Alder adduct 92. There was, however, no H0H 2 C v ^ J^ >s. ^H 2 0H 8

PAGE 81

72 proposed. The infrared spectrum gave a strong 1750 cm. carbonyl from the ester functions. The nmr spectrum had resonances at 57.00 (singlet, aromatic hydrogens, 2), 56.05 (multiplet, vinylic hydrogen, 1), 54.08 (singlet, broad, allylic hydrogens adjacent to bromine, 2), 53.30 (singlet, broad, allylic hydrogens, 4) and centered at 52.30 (two singlets, nonequivalent methyl groups, 3 each). The mass spectrum gave the molecular ion and the molecular ion +2 in the correct percentage for one bromine atom, m/e 339 and m/e 341. The base peak m/e 176 corresponded to the loss of both acetoxy groups and the bromine atom. In the reaction of the acetoxymethyl diene, 79a, with 89_ in benzene at room temperature, quinhydrone, the molecular complex of hydroquinone and quinone, was formed as an insoluble precipitate. It was identified by its melting point, nmr spectrum and mixed melting point with an authentic sample. On evaporation of the benzene a dark oil was formed, which on extraction with hot petroleum ether gave a bright yellow solid which quickly darkened. Column chromatography on silica gel resulted in a yellow oil which quickly darkened also. A thin layer chromatogram yielded two spots. The infrared spectrum gave a strong 3500 cm. absorbance indicative of a hydroxyl group. The nmr spectrum was very complex and from the methyl signal at 52.10, three spikes were apparent indicating a mixture of three compounds. The bridgehead protons for the Diels Alder adduct appeared to be present as a multiplet at 53.25. The downfield region centered at 56.80 appeared as a doublet. From these data it is believed that the initially formed Diels Alder adduct 80a aromatized to %_. From the color and the apparently three different methyl groups, some dehydrogenated material 97_ was possibly present also. All attempts to separate the mixture were unsuccessful. When

PAGE 82

73 the reaction was carried out in ethanol a similar' oily solid was obtained that yielded an infrared spectrum identical to the previous reaction in benzene. H OO 96 H — 0, CH„0CCH, o ' CH OCCH 97 CH nf ,CN '-CN 9 o=c N/\cn CH„ CN 98 The acetoxydiene 79a readily reacted with tetracyanoethylene to yield the Diels Alder adduct 98_. Spectroscopic data and the elemental analysis were all consistent with the normal Diels Alder structure. At the present time, there appears to be no plausible explanation why the Diels Alder adducts of p-benzoquinone, 89^ and the dienes 77a, 77b, 79a and 9^ isomer ize so facile ly to the hydroquinone derivatives or dehydrogenate to the quinone like structures. Since quinhydrone appeared as a byproduct in the formation of 90^ and 96^ 89_ probably acts as an oxidizing agent in the reactions. Although these reactions appear to be the first time such reactions have been observed to occur spontaneously, Ansell and Knights have reported the facile aromatizations of some Diels Alder adducts of l,l'-acetoxyvinylcyclohexene, 99_, and 8jK They found that in ethanol ft R= -OCCH, R 100 R+ 101 102

PAGE 83

74 at room temperature the normal Diels Alder adduct' 100 , formed in 63% yield. In refluxing methanol, however, the authors observed the formation of 101 and 102 . They of ferred no reasons for their observations but did report that most aromatizations of this nature are catalyzed 64 by acid or by base. A previous synthesis of 100 revealed that melting the adduct and then resolidifying resulted in the formation of 101. 2-Cyclohexene-l-one and diazo q uinone a_s_ dienophiles As an alternative approach to the synthesis of a precursor capable of undergoing the cyclization reaction to the cage structures, it was decided to employ dienophiles whose adducts were incapable of undergoing the facile aromatization reaction. The two dienophiles selected for this study were 2-cyclohexene-l-one 103 and diazoquinone 104. J* 103 104 If the normal Diels Alder adduct, 105 , of 103 and 79a were to form then it would not be capable of aromatizing. Hence it was believed that the reactions shown in Scheme VI could be followed. The synthesis of 103 was accomplished by bromination of cyclohexanone with N-bromo.iuccinimide ' followed r ,y d3hydrobromination with collidine. The bromination reaction was accomplished in a 53% yield, while the dehydrohalogenation gave a 58% yield of the desired a,3~unsaturated ketone, an improvement over the 42% yield

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7 5 SCHEME VI 103 + 79a 106 CO CO x CH 2 0CCH 3 separate Mg cl 105 CH OMs S CH 0CCH„~ J base 1) catalytic hydrogenation >reported by the original investigators. An attempted dehydrobromination using lithium bromide in dimethylformamide resulted in a yellow viscous oil. 69 From earlier experiments with 103 by Bartlett and Woods, this dienophile was known to be quite sluggish in the Diels Alder reaction-, therefore forcing reaction conditions were employed. An autoclave attempt to form the adduct from neat reactants at 200°C resulted in a waxy, gummy, polymeric substance. This material gave a sharp carbonyl absorbance at 1710 cm. The nmr spectrum yielded broad resonances centered at 67.00 (1) and 51.00 (13). In benzene solution, in a sealed tube at room temperature for four days, starting materials were recovered. 103 and 79a were then reacted neat, in the presence of a small amount of hydroquinone, in a sealed tube at 190°C for three days. As in the autoclave reaction, a polymeric substance was isolated. It had the identical spectral characteristics of the former polymer.

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76 Aluminum chloride had been found to be an effective catalyst for sluggish Diels Alder reactions. When the Diels Alder reaction of 103 and 79a was attempted in the presence of a catalytic amount of anhydrous aluminum chloride, a vigorous exothermic reaction was noted and could only be controlled by use of an ice bath. On work up, an oil was obtained that yielded a double carbonyl absorbance at 1680 cm. and 1710 cm. Chromatography on silica gel resulted in an oil with a strong 1705 cm. absorbance and no 1680 cm. absorbance. The nmr spectrum exhibited resonances consistent with structure 107 with 65.85 (multiplet, vinyl hydrogen, 1), 54.05 (singlet, allylic hydrogens next to chlorine, 2) and 52.20 (multiplet, broad, ring hydrogens, 12). No resonances that could be assigned to the acetoxy methyl hydrogens were present. The mass spectrum gave a parent peak at m/e 198 with a P+2 peak at m/e 200 which was 35% of the parent. The theoretical P+2 intensity for one chlorine atom is 32.6%. The base peak of the spectrum was m/e 163 corresponding to loss of the allylic chlorine atom. .CH 2 C1 107 The mechanism is not known for the formation of 107 but one could speculate that the initial Diels Alder adluct, which appears to be present in small yield from the infrared spectrum, reacts with adventitious hydrogen chloride present. It is generally known that a trace amount of this impurity is contained in aluminum chloride.

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77 The use of diazoquinone, 104 , as a dienophil'e was believed to be an attractive course of action to pursue to obtain an adduct incapable of aromatizing. Scheme VII shows the intended reaction sequence. 54 Kealy had reported the synthesis of 104 and had reported it to be an extremely potent dienophile. SCHEME VII CIUOR CH OR 1) catalytic hydrogenation 2) MsCl The synthesis of 104_ was accomplished by oxidation of the potassium salt of maleic acid hydrazide with tert-butyl-hypochlorite at -77°C in acetone. Reaction of 104 with the diacetoxydiene 77a at -55°C for twelve hours yielded 45% of a light yellow crystalline solid which was consistent with structure 108a in every respect. The infrared spectrum gave the ester carbonyl at 1730 cm. and the quinone amide carbonyl at 1650 cm. The nmr spectrum gave resonances at 66.92 (singlet, vinyl hydrogens, 2), 54.80 (singlet, allylic hydrogens adjacent to nitrogen, 4) ; 64.57 (singlet, allylic hydrogens adjacent to acetoxy, 4) and 62.09 (singlet, methyl hydrogens, 6). The elemental analysis agreed with the calculated value. The reaction of 104 with the dihydroxy diene 77b yielded the

PAGE 87

/3 Diels Alder adduct lG8b . Again all spectral characteristics were consistent with the assigned structure. The infrared spectrum gave absorbances for the hydroxyl groups at 3480 cm. and 3400 cm.~ x The amide like carbonyl appeared at 1630 cm. The nmr spectrum had resonances at 56.98 (singlet, vinylic hydrogens, 2), 64.51 (singlet, allylic hydrogens adjacent to hydroxyl, 4), 64.11 (singlet, allylic hydrogens adjacent to nitrogen, 4) and 63.50 (broad, probably hydroxyl hydrogens, no integration). The elemental analysis agreed with the calculated values. Attempted catalytic hydro genat ion of Diels Alder adducts The catalytic hydrogenations of the adducts 108a and 108b to the desired structure for the cyclizations were unsuccessful. Two catalyst systems were employed and both were chosen for their efficient reduction of double bonds and their inactivity toward hydrogenolysis of reactive substituent groups. The catalyst system, 5% rhodium on carbon, has been successfully 72 used in the reduction of compound 110 to 111 . Hydrogenation using 5% palladium on carbon has been found to be efficient in systems Rh/C . >o--C-0 110 containing allylic acetoxy groups. Compound 112 was reduced to 113 73 using this system.

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79 ° ° fccH 3 oL, Pd/C >111 113 The results of the hydrogenatlon attempts are shown in Table 7. In all cases, a mixture of products appeared to be present from the complex nmr spectra. Attempts at separation by column chromatography were almost unanimously unsuccessful. Two distinct trends, however, were apparent from these experiments. The first was that the quinone like double bond was easily hydrogenated and the tetrasubstituted double bond was highly resistant to reduction. In all atmospheric hydrogenations almost always approximately one-half of the theoretical hydrogen uptake was recorded in the first fifteen minutes. In experiment 3, the hydrogenation of 1 08b with 5% rhodium on carbon in ethyl acetate, a compound was isolated and purified and assigned structure 114. The nmr spectrum showed an absence of the CH OH 114 quinodial protons of the starting material and gave resonances at 64.29 (singlet, allylic hydrogens adjacent to hydroxyl, 4), 64.10 (singlet, allylic hydrogens, 4), 53.87 (singlet, broadened, hydroxyl hydrogens) and 62.60 (singlet, hydrogens adjacent to carbonyl, 4).

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80 In a hydrogenation attempt under more forcing conditions, i.e., 5% rhodium on carbon at 35 psi., a white crystalline solid was isolated that melted at 151-4°C. The nmr spectrum was indicative of structure 115 which could result from the hydrogenolysis of a carbon nitrogen bond. The resonance signals recorded were 64.31 and 64.13 (two overlapping broad singlets, allylic hydrogens, 4), 62.65 (singlet, hydrogens adjacent to the carbonyls, 4) and 61.75 (broad singlet, allylic methyl hydrogens, 3). The mass spectrum gave the correct parent peak at m/e 228 and the base peak at m/e 210. II CH ' -CH 2 0H *S X^*" CH o 0H II 2 115 s. , s. r if The resistance to hydrogenation of the tetrasubstituted double bond was not surprising since at least one report of a similar case 74 is documented in the chemical literature. Gillis and Beck attempted to hydrogenate 116 with Pd/C, Rainey nickel and Pd/Al„)_ at 59 psi and were unsuccessful. N-COCH CH N-j^0CH„CH_ 116 Hydrogenation of the double bonds of compound 90_ was recognized as another route to lh_. At atmospheric pressure hydrogenation with 5% rhodium on carbon in ethyl acetate resulted in the absorption

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81 TABLE 7. CATALYTIC HYDROGENATION OF DIAZOQUINONE ADDUCTS Conditions Product Experiment

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82 B. Attempted Synthesis of 5 ,5 ,6 ,6-Tetrasubstituted Cyclohexadiene Structures Proposed syntheses Two synthetic routes were investigated as possible means to generate 5 ,5 ,6 ,6-tetracyanocyclohexadiene, 29_. Earlier work had shown that the Diels Alder adduct of butadiene and tetracyanoethylene, 117, was resistant to halogenation reactions. The routes investigated CN C . H 3 , CH 3 CN ,^0 O 117 118 119 were the reaction of tetracyanoethylene with a-pyrone, 118 , and with 3,4-dimethylthiophene-l,l-dioxide, 119, and then subsequent loss of carbon dioxide or sulfur dioxide to the desired tetrasubstituted diene. Adducts of q-pyrone 118 was synthesized by the excellent preparation of Zimmerman and coworkers. 7 Surprisingly the cisoid diene failed to form the desired Diels Alder adduct with tetracyanoethylene under a variety of conditions. Upon mixing the two reactants, a strong reddish-brown color was always observed; however either starting materials or black tars were recovered from each reaction as summarized in Table 8. The failure of tetracyanoethylene to form a Diels Alder adduct with 118 is surprising since this diene has been observed to be quite 77 reactive with rather unreactive dienophiles. Fieser and Haddadin observed 118 to react with the unusual dienophile 120 to yield 121 .

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83 118 CrO 120 121 78 Diels and Alder observed the formation of the Diels Alder adduct with maleic anhydride. This reaction was successfully repeated. Successful Diels Alder additions of 118 with both p-benzoquinone and fumaronitrile to yield 122 and 123 were observed. 122 was .-.0 A o-c*' 1 1 122 ° 123 characterized by the infrared spectrum which gave both a 1750 cm. ester carbonyl and a 1655 cm. quinone carbonyl. The nmr spectrum yielded resonances at 66.82 (singlet, quinone hydrogens, 2) 66.57 (triplet, vinylic hydrogens, 2), 65.69 (quartet, allylic hydrogens next to oxygen, 1), 64.21 (quartet, hydrogen next to carbonyl, 1) and 63.60 (two doublets, bridgehead hydrogens, 2). The elemental analysis was satisfactory for 122 . The fumaronitrile adduct, 123, gave weak infrared absorbances for the nitrile groups at 2245 cm. and 2200 en. The ester carbonyl abscrbance was at 1755 cm. The nmr spectrum gave resonances at 56.92 (multiplet, vinylic hydrogens, 2), 55.80 (multiplet, hydrogen adjacent to oxygen, 1), 64.08 (multiplet, unassigned, 2) and 53.63

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84 (multiplet, unassigned, 1). A correct elemental analysis was obtained. Both dimethyl maleic anhydride and tetraethylethylenetetracarboxylate failed to form the Diels Alder adduct also. It is probable that tetracyanoethylene along with these two dienophiles failed to react because of steric interferences. Under the forcing conditions, where the tars were obtained, it is possible that the adduct formed, lost carbon dioxide and then the resulting diene thermally polymerized under the severe reaction conditions. Adducts of 3,4-dimethylthiophene-l ,1-dioxide 3,4-Diraethylthiophene-l,l--dioxide, 119 , was prepared by first the bromination of 2 ,3-dimethylbutadiene sulfone 82~to the dibromide 124 and then dehydi'ohalogenation with sodium methoxide in tetrahydro— furan. The results of this reaction were not reproducible. Sometimes 119 , the desired product, was formed in good yield, while at other times 79 125 was formed. The literature preparation of 119 involved oxidation -Br if: h Xs '°2 125 of the corresponding thiophene to the thiophene dioxide. A reported dehydrobromination of 124 with potassium hydroxide only yielded 125_119 was found to be unreactive with tetracyanoethylene in the same manner as was ct-pyrone. However, maleic anhydride reacted with 119 in refluxing toluene' to form 126 . This compound was identified by its infrared spectrum with an

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85 TABLE 8. REACTIONS OF TETRACYANOETHYLENE WITH a-PYRONE Experiment

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CHAPTER IV Experimental A. General All melting points and boiling points are uncorrected and reported in degrees centigrade. Melting points were determined in open capillary tubes on a Thomas-Hoover capillary melting point apparatus. Pressures are reported in millimeters of mercury. Elemental analyses were done by Galbraith Laboratories, Inc., Knoxville, Tennessee, Peninsular ChemResearch, Inc., Gainesville, Florida or Atlantic Microlab, Inc., Atlanta, Georgia. Infrared spectra were recorded with either a Beckraan IR 10 or a Beckman IR 8 Spectrophotometer. Visible spectra were recorded on a Beckman DK-2A Spectrophotometer. Proton nuclear magnetic spectra were obtained by use of a Varian A-60 Spectrometer and all resonances are given in the chemical shift parameter 6 and are measured from tetramethylsilane (TMS) as an internal standard. Mass spectral data were obtained using a Hitachi Perkin-Elmer RMU mass spectrometer. All solvents were commercial reagent grade and used as received unless specifically noted. Polymer nonsolvents were technical grade and were filtered before use. All chemicals used as reactants were obtained commercially and used as received unless specifically designated as otherwise. The comonomers divinyl ether, ethyl vinyl ether, isobutyl vinyl ether, styrene, acrylonitrile, divinyl sulfone and vinyl acetate were 36

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87 obtained from commercial sources and distilled immediately prior to use. Divinyl carbonate and N-yinyl carbazole were obtained in high purity from commercial sources and used without further purification. Number average molecular weights were obtained from a Mechrolab Model 302 Vapor Pressure Osmometer. Molecular weight distributions were obtained from a Waters Associates GPC 300 Gel Permeation Chromatograph. Thermal characteristics of the polymers were recorded by a Perkin-Elmer DSC1B Differential Scanning Calorimeter. Intrinsic viscosities were measured employing a Cannon-Ubbelohde semimicro dilution viscometer using standard procedures for operation and calculations. B. Copo lymeri zations and Related R eactions of 4-Substituted 1,2 ,4tri azoline-3 , 5-diones 1 ._ Syn thesis of 4 -phenyl and 4-methyl-l ,2 , 4-triazoline-3, 5-dione s 31 Ethyl carbazate -Diethyl carbonate (20,00 g. , 1.80 mol.). and 88.0 g. (1.80 mol.) of 99% hydrazine hydrate were shaken together for approximately 20 minutes. Some exothermicity was observed and after this time the original two phase system blended into one phase. The solution was left standing overnight. Distillation at 95°C and 12 mm. yielded 147.7 g. (83.5%) of a clear liquid which solidified on standing to a white solid, m.p. 43-45.5° (lit. 44-45.5*). 82 l-Ethox ycarbon y].-4-phenylse micarbazide -Ethyl carbazate (70.0 g., 0.67 mol.) was placed into a 500 ml. round-bottomed, three-necked flask with 350 ml. of benzene. The flask was equipped with a magnetic stirrer, a reflux condenser guarded by a calcium chloride drying tube, a dropping funnel and a thermometer. After refluxing to get the

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83 ethyl carbazate into solution, the solution was cooled to 10°. Through the dropping funnel 70.0 g. (0.59 mol.) of phenyl isocyanate were introduced at a rate which kept the temperature between 10° and 20°. After all the isocyanate was added, the resulting white solid slurry was refluxed for 20 minutes and then cooled and filtered. After drying on under vacuum 124 g. (89%) of the desired product m.p. 152-3° (lit. m.p. 154°) were obtained. 82 4-Phenyl urazole -To 275 ml. of hot 4M potassium hydroxide, 124 g. (0.55 mol.) of l-ethoxycarbonyl-4-phenylsemicarbazide were added in small portions while shaking the potassium hydroxide solution on a steam bath. After the addition was completed, the solution was maintained on the steam bath for an additional 20 minutes. The solution was cooled and carefully acidified with concentrated hydrochloric acid. The precipitate was removed by vacuum filtration and extracted with 95% ethyl alcohol via a Soxhlet extractor. On cooling and then treating the mother liquor 69.2 g. (70.3% yield) of the urazole m.p. 204-7° (lit. 82 m.p. 206-7°) was obtained. 4-Phenyl-l,2 , 4-triazoline-3,5-dione , PhTD -Anhydrous sodium sulfate, 25.0 g., was placed into a 500 ml. Erlenmeyer flask with 300 ml. of methylene chloride and 6.0 g. (0.034 mol.) of 4-phenyl urazole. The slurry was stirred by a magnetic stirrer and cooled to 0-5° with an ice-water bath. By means of a pipette attached to a gas cylinder with a tube, dinitrogen tetroxide was bubbled slowly through the solution. The temperature was kept below 5°.. .after a few minutes a deep red color developed. After all the urazole appeared to have been consumed, usually in about thirty minutes, the sodium sulfate was removed by vacuum filtration and the deep red solution was

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89 evaporated using lukewarm water on a rotary evaporator. 4.8 g. (80% yield) of dark red crystalline PhTD was obtained. Purification was accomplished by sublimation at 70-75° under a vacuum of less than 0.5 mm. The red solid was stored in the absence of light in a freezer until it was used. 4-Methyl~l ,2 ,4-triazoline-3,5-dione , MID -The same procedure used in the synthesis of PhTD was employed in the synthesis of MTD. This synthesis had been previously reported in the literature. Methyl isocyanate was added to the ethyl carbazate and a quantitative yield of the corresponding semicarbazide derivative was obtained. This was cyclized with 4M potassium hydroxide to the corresponding 4-methyl urazole in a yield comparable to the phenyl derivative. Oxidation with dinitrogen tetroxide was accomplished in approximately 90% yield. The light red fluorescent appearing powder was purified by sublimination at less than 0.1 mm. and a temperature between 50 and 60°. 2j_ General c opolymer izat ion procedures a. Spontaneous copolymer i z at ions The following experimental procedure was typical of all spontaneous, room temperature ccpolymerizations unless specifically noted otherwise. All glassware, i.e., Erlenmeyer flasks, syringes and volumetric flasks were scrupulously cleaned, rinsed with acetone, dried in an 80° oven and then allowed to cool to room temperature in a large desiccator. On removal from the desiccator the flasks were immediately capped with serum caps. Solvents were reagent grade and dried for a minimum of 24 hours over 3A molecular sieves. Ethyl vinyl ether, EVE, PhTD copoly aerizationA 50 ml. Erlenmeyer

PAGE 99

90 flask equipped with a magnetic stirring bar and a rubber serum cap was charged with 0.499 g. (2.34 mmol.) of PhTD by removing the cap and adding as a solid. Next, 15 ml. of methylene chloride were introduced using a syringe and adding through the serum cap. This was followed by the addition of EVE (0.203 g., 2.83 mmol.) in the following manner. The vinyl ether was carefully weighed into a 10 ml. volumetric flask through a serum cap and then the flask was brought to volume with methylene chloride. A careful quanitative transfer to the reaction vessel was made using a syringe. The reaction mixture was stirred and within two minutes the dark red colored solution, characteristic of PhTD, was discharged to yellow. After 30 minutes the reaction mixture was precipitated by dropping slowly through a coarse filter frit into cold hexane. The hexane solution was filtered to yield 0.615 g. (86% yield) of a white-yellowish granular appearing solid. The solid appeared to soften at 100° and above 150° it darkened and decomposed. The number average molecular weight was determined to be 1660 by use of a Vapor Pressure Osmometer in acetone solution. The infrared spectrum (KBr) shewed absorbances at 2980 (w) , 1770 (w) , 1715 (s) , 1610 (s), 1500 (m) , 1470 (m), 1420 (n) , 1310 (m) , 1130 (m) , 1070 (w) , 900 (w) , 820 (w) , 760 (m) and 700 (m) cm. The nmr spectrum (CDC1 ) gave resonance signals at 67.45 (s , broadened, 5), 66.00 (m, broad, 1), 63.83 (m, broad) and 61.16 (t, broad, 3). The spectrum is shown in Fig. 1. A nal. Calcd. for a 1:1 copolymer structure, C. H N : C, 58.30; 1Z ij 3 3 H, 5.26; N, 17.00. Found: C, 58.08; H, 5.14; N, 17.16. Table 1 contains a summary of experimental results of all EVEPhTD copolymerizations.

PAGE 100

91 b. Cop olymer izat ions at 60° The following experimental procedure was typical of all copolymerizations at 60° unless specifically noted otherwise. The copolyrr.erizations were effected in heavy walled 13 cm. x 3 cm. Pyrex tubes. All glassware i.e., Pyrex tubes, syringes and volumetric flasks was thoroughly cleaned, rinsed with acetone, dried in an 80° oven and then allowed to cool to room temperature in a large desiccator. On removal from the desiccator the volumetric flasks and the polymer tubes were sealed with serum caps. Solvents were reagent grade and were dried for a minimum of 24 hours over 3A molecular sieves. Copolymerizations were conducted in a 60° oil bath regulated by a Sargent NS112 controller to 0.1". Copolym er izat ion of_ divinyl ether, DVE, and PhTD at 60° -A heavy walled Pyrex polymer tube, capped with a serum cap, was charged with 0.508 g. (2.81 mmol.) of PhTD by removing the cap and adding the solid. This was followed by the addition of 15 ml. of methylene chloride by. means of a syringe. Next DVE (0.200 g., 2.82 mmol.) was carefully weighed into a 10 mi. volumetric flask using a syringe and adding through a serum cap. The flask was brought to volume with methylene chloride and then carefully transferred to the polymer tube by means of a syringe. The polymer tube was then placed on the high vacuum line -4 and carried through a freeze-thaw degassing cycle using a 10 mm. vacuum. The tube was sealed and warmed to room temperature before placing in the 60° bath. After 24 hours at 60° the originally red colored solution had changed to yellow. This color change normally took place within a few minutes after placing the tube in the bath. The tube was removed from the oil bath after 24 hours, cooled to room temp-

PAGE 101

92 erature and opened. Precipitation of the copolymer was accomplished byfiltering the reaction product through a coarse frit into rapidly stirred hexane. A white electrostatic polymeric material, 0.602 g. (86% yield), was obtained. This product softened at 105° and decomposed at 170°. The number average molecular weight was 1590. The infrared spectrum (KBr) showed absorbances at 1770 (in), 1720 (s) , 1640 (m) , 1610 (s) , 1500 (m), 1470 (m) , 1450 (m) , 1425 (m) , 1310 (m) , 1160 (m) , 1070 (m) , 1000 (w), 945 (m), 855 (m) , 760 (m) and 695 (m) cm." The nmr spectrum (CDC1 ) gave resonance signals at 67.39 (s, broad, 5), 66.25 (m, broad, 2) and 64.82-53.50 (m, broad, 4). The nmr spectrum is shown in Fig. 3. Anal . Calcd. for 1:1 copolymer structure c 1 2 H n^3°3 : C ' 58 80 ; H, 4.50; N, 17.20. Found: C, 58.60; H, 4.56; N, 17.17. A summary of the DVE-PhTD copolymerizations is given in Table 2. 3. C opolymerizations of vinyl ethers and PhTD S pontaneous copolym e rization of_ DVE and PhTD The standard method for spontaneous copolymerizations was followed with the flask charged with 0.502 g. (2.87 mmol.) of PhTD, 0.199 g. (2.85 mmol.) of DVE and 25 ml. of methylene chloride. A discharge of the red color was noted in 15 minutes and the contents were precipitated into hexane after 30 minutes. A white solid, 0.477 g. (77.5% yield), was obtained whose number average molecular weight was determined to be 450. The infrared spectrum (KBr) exhibited absorbances at 1770 (m) , 1710 (s), 1640 (w), 1610 (m), 1500 (in), 1425 (m) , 1310 (w) , 1160 (m) , 1025 (w), 850 (w), 770 (m) , and 695 (m) cm.~ The nmr spectrum (CDCl^ gave resonance signals at 57.49 (s , with upfield spikes, 5), 66.50

PAGE 102

9 3 (q, 1), &5.71 (t, 1) and 65. 00-53. SO Cm, 4). Anal. Calcd. for C H N (1:1 structure): C, 58.80; H, 4.50; N, 17.20. Found: C, 57.87; H, 4.45; N, 17.65. Preparation of 3-phenyl-6-vinyloxy-l , 3 , 5-triazablcyclo [3.2 . Ojhepta2,4-dioneAn identical procedure to the previous DVE-PhTD reaction at room temperature was followed. The reaction mixture was precipitated into hexane (not cooled) and after filtration of the solid the filtrate was placed into an ice-water bath for about two hours. A white solid crystallized out and filtration of this solid yielded 0.15 g. of pure 31b m. p. 128-29°. The infrared spectrum (KBr) showed absorbances at 3080 (m) , 3040 (w), 2990 (w), 1795 (m) , 1730 (s) , 1710 (s) , 1645 (n) , 1625 (m) , 1600 (m), 1505 Cm), 1455 (w) , 1420 (m) , 1365 (ra) , 1330 (m) , 1290 (m) , 1240 (m), 1200 (w), 1160 (s), 1130 (m) , 1110 (m) , 1070 (w) , 1020 (m) , 950 (m), 875 (m), 845 (m) , 810 (w) , 725 (m) and 655 (m) cm." 1 . The nmr spectrum (CDC1„) gave resonances at 67.40 (s , 5), 66.60 (q, 1), 65.90 (t, 1) and 64.50 (m, 4). The mass spectrum (70 eV) gave the following fragments, m/e (rel. intensity): 246 (10), 245 (M+, 69), 216 (3), 203 (6), 202 (9), 177 (8), 176 (9), 170 (3), 160 (3), 155 (8), 149 (17), 148 (6), 147 (12), 141 (12), 120 (22), 119 (100), 97 (5), 91 (23), 84 (5), 83 (14), 77 (8), 70 (44), 64 (4) and 57 (9). Anal. Calcd. for C^H^N^: C, 58.80; H, 4.50; N, 17.20. Found: C, 58.88; H, 4.61; N, 17.24. Attempted rad ical initiated copolymerizatio n of PhTD and DVE by p hotolysi s of benzo yl peroxideA polymer tube was charged with 0.500 g. (2.84 mr.ol.) of PhTD, 0.032 g. of benzoyl peroxide (0.46 wt.%) and then 15 ml. of methylene chloride were added. The solution was frozen in

PAGE 103

94 liquid nitrogen and then 0.201 g. (2.88 mmol.) of DVE was dissolved in 10 ml. of methylene chloride and introduced into the tube. The contents were frozen (two layers existed-one red and one white) and the tube was degassed on the high vacuum line and sealed. The tube was placed into a -45° ethanol bath in which the temperature was maintained by circulating the ethanol through a dry ice isopropanol bath. The tube was irradiated for nine hours with a Hanovia Utility Ultraviolet Quartz Lamp. The solution gradually lightened in color over this time, but was still pink when the tube was removed and opened. The contents were filtered at dry ice temperature through a dry ice jacketed filter funnel and then quickly added to hexane which had been cooled to -10°. A white solid precipitate formed and was removed by filtration and then dried in vacuo. The filtration was performed with care to keep the hexane from warming. The resulting solid, when redissolved in methylene chloride, gave an insoluble portion (0.19-5 g.) and a soluble portion (0.255 g.). Both solids gave very similar infrared spectra. The infrared spectra were very similar to the spontaneous copolymerization product of DVEPhTD. The nmr spectrum gave identical resonance signals to the spectrum of the spontaneous copolymerization product of the two monomers. Photol y sis of DVE and PhTD-As a control the previous reaction was performed in the absence of benzoyl peroxide. After nine hours of irradiacion 0.389 g. of soluble product were obtained and the spectral characteristics were identical to those from the previous reaction. Copolymeriz ation uf DVE and PhTD at 60° under "dry conditions"The normal procedure for the 60° copolymerization was followed with the following alterations and precautions taken.

PAGE 104

95 Reagent grade methylene chloride was distilled from 3A molecular sieves through a twelve inch column into a flask containing more 3A sieves. The flask was immediately stoppered with a serum cap. The PhTD was dried for two hours in a drying pistol in vacuo at refluxing ether temperature and the DVE was distilled into 3A molecular sieves and left for 24 hours before use. A polymer tube and a 10 ml. volumetric flask were dried overnight in an oven and then connected to a vacuum pump, flamed out, cooled in a desiccator and then stoppered with serum caps. The PhTD was transferred to the polymer tube in a nitrogen flushed glove bag. The DVE was added in the usual manner by means of a syringe. The monomer charge was 0.500 g. (2.85 mmol.) cf PhTD and 0.197 g. (2.31 mmol.) of DVE. After the customary freeze-thaw cycle on the high vacuum manifold the tube was sealed. The reaction was continued for 24 hours and 0.602 g. (86% yield) of product was obtained. The infrared absorbancej of the copolymer were identical to those of other 60° DVE-PhTD copolymers. On dissolving for the molecular weight determination, an acetone soluble fraction (0.422 g.) and an acetone insoluble fraction were obtained. The molecular weight of the soluble fraction was determined to be 2540. DVE-PhTD co pol yme ri zation in the p res ence of a f ree radical inhibitorIn the usual manner for 60° copolymurizations , a polymer tube was charged with 0.499 g. (2.85 mmol.) of PhTD, 0.200 g. (2.86 mmol.) of DVE and 0.010 g. (1.5 wt.%) of m-dinitrobenzene. After placing in the 60° oil bath the solution turned yellow as was usually observed in the 60° copolymerizations. Precipitation after 24 hours yielded 0.459 g. (71.5% yield) of polymeric material. The infrared spectrum of the polymeric material was identical to the other spectra from the DVE-PhTD 60° copolymerizations. Tbe filtrate residue yielded a solid that gave

PAGE 105

an infrared spectrum with the 1610 cm. and 850 cm. bands absent but identical in all other respects. The molecular weight of the polymer was determined to be 2130. Spontaneous copolymer izat ion of PhT D and DVE with a. 2 ;1 feed compositionFollowing the usual procedure for the spontaneous room temperature copolymerizations 0.501 g. (2.85 mmol.) of PhTD and 0.098 g. (1.40 mmol.) of DVE were allowed to react, for 30 minutes in methylene chloride. The red color persisted at the end of the reaction time and precipitation into hexane yielded 0.256 g. (44% yield) of product. The product was not sufficiently soluble in acetone to obtain a molecular weight. The infrared spectrum (KBr) showed a less intense 1610 cm. band and a very weak 860 cm. band when compared to the usual DVE-PhTD spontaneous products. The nmr spectrum gave the same signals as the 1:1 feed composition 60° DVE-PhTD copolymerizations with the aromatLc region enhanced to approximately twice its absorbance in the 1:1 copolymers. Copolymer izat ion of PhTD and DVE at_ 60° with a_ 2 :1 feed composit ionA polymer tube was charged in the usual manner, but with 0.502 g. (2.85 mmol.) of PhTD and 0.099 g. (1.41 mmol.) of DVE. After 24 hours the usual yellow color was observed; however, considerable white fluffy solid was present. After filtering the insoluble portion (0.021 g.), precipitation into hexane yielded 0.545 g. (91.0% yield) of soluble product. The insoluble portion gave an infrared spectrum (KBr) with the following absorba^ces .• 1775 (m) , 1710 (m) , 1600 (m) , 1495 (m) , 1420 (m) , 1395 (m), 1290 (m) , 1245 (m) , 1145 (m) , 1105 (m) , 1070 (m) , 1045 (m) , 1020 (m), 940 (m),*875 (m) , 835 (m) , 735 (m) , 7/5 (m) , 740 (m) and 690 (m) cm."

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97 Anal. Calcd. for C OA H~ .N.0 C (2:1 copolymer): C, 57.20; H, — — 20 16 6 5 3.82; N, 20.00. Found: C, 54.45; H, 3.70; N, 19.02. The soluble portion gave an infrared spectrum (KBr) showing absorbances at 1775 (m) , 1715 (s), 1640 (w) , 1610 (m) , 1495 (m) , 1420 (s), 1310 (m), 1290 (m) , 1265 (m) , 1150 (ra) , 1070 (m) , 1025 (m) , 940 (w), 860 (w), 765 Cm) and 695 (m) cm." 1 Anal . Calcd. for C i 2 H 11 N 3 3 C 1:1 copolymer): C, 58.80; H, 4.50; N, 17.20. Found: C, 55.63; H, 4.10; N, 1885. Copolymerization of DVE and MTD at 60° -Using the typical procedure for 60° copolymerizations, MTD (0.324 g. , 2.86 mmol.) and DVE (0.198 g. , 2.83 mmol.) were reacted in a sealed tube in methylene chloride for 24 hours. The red color faded as usual to yellow. Precipitation into hexane yielded 0.264 g. (50.0% yield) of yellowish-white powdery electrostatic product. The infrared spectrum (KBr) gave 2950 (w) , 1770 (m), 1720 (s), 1640 (m) , 1610 (s)-, 1510 (ra) , 1480 (m) , 1400 (m) , 1230 (m) , 1160 (m), 1115 (w), 1030 (w) , 995 (w) , 860 (m) , 770 (m) and 750 (m) cm." The nrar spectrum (CDC1 ) gave resonance signals at 66.33 (broad, 2), 64.33 (broad, 4) and 63.03 (s, 3). The nmr spectrum is shown in Fig. 4. Co polymer izat ion of DVE and M TD at 60° with free radical initiatorThis experiment was identical to the preceding copolymerization except for the addition of 0.5 wt . % of azobisisobutyronitrile. A yellowishwhite powder was obtained as before and Its infrared spectrum was identical to the reaction performed without initiator. A molecular weight of 900 was obtained. Spontaneous copolymerization of MTD and EVEIn the usual manner for room temperature polymerizations 0.452 g. (4.00 mmol.) of MTD and 0.283 g. (3.95 mmol.) of EVE were polymerized for 30 minutes in 25 ml.

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98 of methylene chloride. The red color was not completely discharged after this time, but was still a faint pink. Precipitation of the methylene chloride solution into hexare resulted in a pink jelly like material. Redissolving in methylene and precipitating into ether and then redissolving this product into acetone and precipitating into ether yielded only a few milligrams of solid product. The infrared spectrum (KBr) yielded tibsorbances at 2980 (w) , 1770 (m) , 1705 (s) , 1470 (s), 1400 (in), 1270 (broad, w) , 1240 (broad, w) , 1100 (m) , 1050 (broad, m) , 760 (m) and 720 (w) cm. Copolymerization of PhTD and isobu tyl vinyl ether , IVEThe comonomers PhTD (0.500 g. , 2.80 mmol.) and IVE (0.280 g., 2.80 mmol.) were reacted in the usual manner for spontaneous copolymerizations . Within 10 minutes the red color had discharged to yellow. Precipitation into hexane yielded 0.400 g. (51.5% yield) of a white electrostatic polymer. The infrared spectrum (KBr) showed absorbances at 3080 (w) , 2975 (m) , 2960 (w), 2880 (w) , 1770 (in) , 1720 (s) , 1610 (m) , 1500 (m) , 1420 (m) , 1250 (w), 1170-1000 (m, broad), 910 (w) , 760 (m) and 685 (m) cm." The nmr spectrum (CDC1„) gave resonance signals at 67.30 (m, broad), 66.20 (m, weak, broad), 54.00-63.00 (ra, broad), 61.70 (broad, m) and 50.80 (m, broad). The spectrum was not integrated because of its complex nature. Ca talyt ic hydro genation of the DVEPhTD copolymer with 5% Rh/C in ethyl acetateA catalytic hydrogenation flask for an atmospheric pressure hydrogenation apparatus was charged with 0.149 g. of the DVEPhTD copolymer, 50 ml. of ethyl acetate and 0.115 %. of 5% Rh/C catalyst. At atmospheric pressure only 5 ml. of hydrogen were absorbed. Application of a small pressure via the mercury measuring column gave an uptake of 21.1 ml., whereas a blank under the same conditions absorbed 11.2 ml.

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09 The net, 9.9 ml., was only 66.0% of the theoretical 15 ml. for a 1:1 copolymer with, structure 4l_. An nmr spectrum of the product CCDC1 ) showed resonance signals at 67.38, 56.10-65.30, 64.30-63.20, and 61.4060.83. Catalytic hydrogenatlon of the DVE-PhTD c opolymer with _5 % Pd/Al in ethyl acetate -The catalytic hydrogenator was charged with 0.168 g. of the DVE-PhTD copolymer, 0.135 g. of 5% Pd/Al and 75 ml. of ethyl acetate. The hydrogen uptake was exactly equal to the theoretical after subtraction for the blank. The infrared spectrum had three distinctive changes, i.e. , the 1640 cm. band, the 1610 cm. band, and the 850 cm. band disappeared. The nmr spectrum (CDC1„) gave resonances at 67.38, a much decreased resonance at 66.50, a broader resonance from 55.00 to 63.00 and a large resonance at 51.20. No integration was taken because of the broadness. The original molecular weight of 1590 was reduced to 490. Catalytic h ydrogenation of the EVEP hTD copolymer with 5% Pd/Al^O in ethyl acetateThe same procedure used for hydrogenation of the DVEPhTD copolymer was followed. The hydrogenation flask was charged with 0.165 g. of EVE-PhTD copolymer, 75 ml. of ethyl acetate and 0.127 g. of 5% Pd/Al 0„. At first it appeared as if more hydrogen than the blank was absorbed; however after a couple of hours the amount measured was identical to that measured for the blank. The infrared spectrum was identical to the original copolymer except the strong 1610 cm. had disappeared.

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100 4_. Interception of the 1,4-dipole of PhTD and vin yl e thers by Ketone solvents Spontaneous reaction of PhTD and EVE in acetone-PhTD (0.500 g. , 2.85 mraol.) was placed into a 50 ml. Erlenmeyer flask equipped with a magnetic stirring bar and a serum cap. Using a syringe, acetone (15 ml.) was introduced and a deep red solution resulted. EVE (0.199 g., 2.80 mmol.) dissolved in 10 ml. of acetone was added in like manner. After 30 minutes the dark red color had faded to a slight pink-tinged solution. The acetone was removed on a rotary evaporator at ambient temperature. The solid product was dissolved in methylene chloride (15 ml.) and then precipitated by slowly dropping into 300 ml. of hexane. A white polymeric solid was removed by filtration and the resulting yellow filtrate carefully evaporated to dryness on a rotary evaporator. The light yellow crystalline product (0.361 g., 42% yield) was recrystallized from absolute ethenol to give pure _49_, m.p. 149-51°. The infrared spectrum (KBr) showed absorbances at 2980-2880 (m) , 1770 (s), 1710 (s), 1600 (w) , 1490 (m) , 1420 (s) , 1390 (m) , 1280 (w) , 1250 (m), 1245 (w) , 1205 (w) , 1170 (m) , 1150 (m) , 1130 (m) , 1080 (w) , 1030 (m), 990 (m) , 950 (m) , 880 (w) , 855 (w) , 815 (w) , 780 (m) , 740 (m) , 710 (m), 690 (m), 650 (m) and 610 (m) cm." 1 The nmr spectrum (CDC1„) showed resonance signals at 57.40 (m, 5), 65.02 (q, 1), 63.73 (m, 4) , 61.85 (s, 3), 61.70 (s, 3) and 61.25 (t, 3). The mass spectrum (70 eV) gave the following fragments, m/e_ (rel. intensity) 305 (M+, 4), 260 (7), 248 (17), 247 (100), 219 (8), 218 (22), 205 (7), 191 (13), 190 (59), 177 (2), 174 (2), 159 (4), 149 (2), 148 (4), 128 (4), 120 (18), 119 (27), 99 (11), 81 (10), 77 (7), 72 (26) and 71 (24). Anal . Calcd. for C i5 H 19 N 3 a : c » 59.00; H, 6.24; N, 13.79.

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101 Found: C, 59.03; H, 5.33; N, 13.79. The white polymeric solid was formed in 40% yield (0.283 g.). It was reprecipitated twice from methylene chloride into hexane. The nmr spectrum was characteristic of the EVE-PhTD copolymers with broad resonances centered at 67.41, 56.00, 64.00 and 61.15. A new resonance appeared at 62.12 as a broad singlet. It did not decrease in intensity after the two reprecipitations and was assigned to acetone incorporated into the polymer. A calculation based on its relative intensity indicated about 20% incorporated. Spontaneous reaction of PhTD and IVE in ac etoneThe experimental procedure followed was identical to the EVE case except isobutyl vinyl ether (IVE) was used in place of EVE. The light yellow product was recrystallized from absolute ethanol to give pure 50_, m.p. 125-6° in 47% yield. The infrared spectrum (KBr) showed absorbances at 2980-2880 (m) , 1770 (s), 1710 (s), 1600 (w) , 1490 (s) , 1470 (m) , 1445 (m) , 1415 (s) , 1380 (s), 1280 (m), 1250 (m) , 1245 (m) , 1205 (m) , 1170 (s) , 1130 (s) , 1090 (m), 1035 (s) , 1015 (m) , 990 (m) , 950 (m) , 915 (w) , 880 (w) , 855 (w), 815 (w), 780 (m), 740 (m) , 710 (w) , 690 (m) and 610 (w) cm. -1 The nmr spectrum (CDC1„) showed resonance signals at 67.42 (m, 5), 65.00 (q, 1), 63.50 (m, 4), 61.85 (s, 3), 61.70 (s, 3) and 60.95 (d, 6). The mass spectrum (70 eV) gave the following fragments, m/e (rel. intensity) 333 (M+, I), 276 (4), 275 (20), 261 (1), 260 (7), 219 (6), 218 (30), 191 (30), 190 (100), 177 (1), 162 (1), 149 (1), 148 (1), 141 (1) , 135 (2), 134 (1), 120 (15), 119 (22), 100 (2), 91 (8), 84 (5), 77 (5), 71 (18), 59 (24), 58 (3-), 57 (30) and 56 (29). Anal . Calcd. for C H N : C, 61.30; H, 6.90; N, 12.61.

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102 Found: C, 61.49; H, 6.98;. N, 12.47. Spo ntaneou s reaction of P hTD and EVE in c yclohexanoneThe experimental procedure followed was identical to the two previous cases with a change in the work up due to the high boiling point of cyclohexanone. The cyclohexanone was removed by vacuum distillation at 60°. The resulting oily residue was dissolved in methylene chloride and added slowly to hexane as before. The gummy polymeric material formed was filtered and the filtrate evaporated to obtain a white solid which was readily purified by recrystallization from absolute ethanol to give a 12% yield of pure 51_. The actual yield was probably much higher but was lowered by the complicated work up procedure. The white needle like crystalline solid melted at 170-71°. The infrared spectrum (KBr) yielded absorbances at 2980-2860 (m) , 1775 (s) , 1715 (s), 1600 (w) , 1490 (m), 1420 (s) , 1385 (m) , 1365 (m) , 1335 (w) , 1285 (w) , 1260 (m) , 1250 (m), 1220 (m) , 1170 (m) , 1150 (in) , 1135 (s), 1070 (m) , 1020 (m) , 980 (m), 970 (m) , 910 (m) , 870 (w) , 850 (w) , 825 (w) , 800 (m) , 770 (m) , 740 (m), 685 (m) , 660 (w) and 640 (w) cm." 1 The nmr spectrum (CDC1.,) gave resonance signals at 67.40 (m,5), 65.10 (q, 1), 53.70 (m, 4), 61.50-62.80 (broad m, 11) and 61.25 (t, 3). The mass spectrum (70 eV) yielded the following fragments, m/e_ (rel. intensity) 345 (M+, 2), 300 (3), 248 (18), 247 (100), 219 (11), 2.13 (21), 214 (3), 205 (8); 191 (12), 190 (37), 177 (3), 162 (1), 149 (1), 148 (4), 135 (2), 128 (5), 121 (2), 120 (21), 119 (29), 99 (15), 91 (10), 81 (14), 77 C7), 71 (26) and 56 0-6). Anal. Calcd. for C. -IL-N-O. :' C, 62.60; H, 6.67; N, 12.17. Found: C, 62.73; H, 6.76; N, 12.32. Spon taneous reaction of FhTD and DVE in acetone-The experimental

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103 procedure followed was identical to the EVE case. The reaction mixture was precipitated into hexane and the solid polymeric material was removed by filtration. The polymeric material gave an nmr spectrum (CDC1_) with broad bands centered at 67.48, 64.48 and two upfield multiplets at 52.20 and 61.80, possibly from incoroporated acetone. The filtrate was evaporated to dryness and an nmr spectrum (CDC1.) of the small amount of solid was indicative of two products. Signals for the 1,2-diazetidine, 31b, were present. Also resonances were present at 66.42 (q, 1), 55.25 (t, 1), centered at 64.30 (complex m, after subtracting for 31b, 4) and 61.75 (s , 6) which were characteristic of the oxadiazine. No other characterization of this product was possible because of its small yield. 5. Reactions and copolymer izat ions of PhTD and other monomers Reaction of PhTD with vinyl acetate , VAC , at_ 60°-The normal procedure for the 60° copolymerizations in sealed tubes was followed. PhTD (0.503 g., 2.86 mmol.) and VAC (0.249 g. , 2.90 mmol.) were reacted for 24 hours in 25 ml. of methylene chloride solution. The red color of PhTD disappeared after four hours. Precipitation in hexane yielded a white solid and as the filtrate cooled under the water aspirator vacuum a white solid began to crystallize from solution. After cooling this filtrate in a freezer for 'two hours, filtration yielded 30% of pure 55_, m.p. 130-31°. The white granular solid gave an infrared spectrum (KBr) that showed absorbances at 3080 (w) , 3005 (w) , 2990 (w) , 2890 (w) , 2860 (w), 2750 (w) , 1800 (m) , 1730 (s) , 1600 (w) , 1495 (m) , 1425 (s), 1390 (m), 1370 (in), 1325 (m) , 1275 (s), 1240 (m) , 1175 (m) , 1145 (m) , 1090 (m) , 1040 (w) , 1000 (w) , 995 (m) , 950 (m) , 875 (m) , 810 (m) ,

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104 755 (in), 690 (m) and 640 (m) cm." The nmr spectrum (CDC1„1 gave resonance signals, all singlets, at 69.56 (s, 1), 57.50 Cs, 5), 64.80 Cs, 2) and 52.60 (s , 3). The mass spectrum C70 eV) gave the following fragments, m/e (rel. intensity) 262 (14), 261 (M+, 100), 220 (11), 219 (86), 191 (11), 176 (11), 175 (11), 132 (18), 131 (36), 122 (11), 121 (14), 120 (18), 119 (79), 104 (89), 93 (25), 91 (32) and 77 (54). Anal. Calcd. for C 12 H 11 N 3°4 : C ' 55 ' 20; H ' 4,22; N > 16 ' 09 Found: C, 55.34; H, 4.28; N, 15.95. The initial solid, 0.186 g. , yielded an nmr spectrum which indicated it was in the most part 55_. Also present were broadened resonances at 67.75, 64.50 (weak) and 62.15. The melting point was recorded as 110-18°. Evaporation of the final filtrate yielded an additional 0.119 g. of impure 5_5. By combining all three products, the total yield of the reaction was 71%. Reaction of PhTD and VAC at room temper a tureThe normal room temperature copolymerization procedure was followed with 0.499 g. (2.84 mmol.) of PhTD and 0.246 g. (2.89 mmol.) of VAC in 25 ml. of methylene chloride. The flask was stirred for 21 hours and upon precipitation of the contents (still pink) 0.426 g. (57.3% yield) of a white solid was obtained. The infrared spectrum was practically identical to the 60° product. The nmr spectrum was identical • to the first precipitated product from the 60° reaction verifying it to be impure 55 . R eaction of PhTD and VAC at 60_°_ in acetoneThe normal 60° reaction conditions were employed with acetone in the place of methylene chloride as the solvent. PhTD (0.502 g. , 2.86 mmol.) and VAC (0.252 g., 2.96 mmol.) were reacted in 25 ml. of acetone. Precipitation into hexane gave a gummy solid which was dissolved and reprecipitated in hex-

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105 ane. The filtered solid gave spectral data indicative of 55. The filtrate was evaporated and a small amount of solid was obtained which yielded an nmr spectrum showing some other compound with the following additional resonances 67.42 (d , one peak from 55), 66.20 (t, 1), 63.75 (d, broad, 2), 62.17 (s , broad, 3) and 51.80 Cs , broad, 6). Since only a very small amount of solid was formed, no other characterizations were made. R eaction of_ PhTD and VAC at 60° in the presence of phenyl isocyanate-This reaction was conducted in an identical manner to the 60° PhTDVAC reaction in methylene chloride with the addition of 2.18 g. CIS. 30 mmol.) of phenyl isocyanate. On opening the polymer tube after 24 hours at 60°, the sharp odor of phenyl isocyanate was noted. Precipitation into hexane yielded a light yellow solid that gave an oily solid which had a strong phenyl isocyanate odor. After setting overnight this oil changed to a white solid. This solid was identified as diphenyl urea from its melting point, i.e., 238-40° (lit. m.p. 241-42°). Copolymer izat ion of PhTD and DVC at room temperatureIn a manner analogous to other room temperature polymerizations 0.499 g. (2.85 mmol.) of PhTD and 0.326 g. (2.86 mmol.) of DVC were reacted for 14.5 hours. The flask was wrapped with aluminum foil to protect the light sensitive divinyl carbonate. The solution, which remained red, was precipitated into hexane and the reddish precipitate obtained was extracted twice with 50 ml. of anhydrous ethyl ether. A white solid was left after the unreacted monomers had been extracted and filtration yielded 0.370 g. (44.9%). The infrared spectrum (KCr) gave the following absorbances: 3080 (w) , 3 775 (s), 1720 (s), 1650 (w) , 1610 (m) , 1600 (m) , 1500 (m) , 1415 Cs) , 1300 (m) , 1250 Cs) , 1150 Cm) , 1100 (w) ,

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106 1070 (m), 1025 (w) , 980 (m) , 940 (w) , 890 Cm), 760 (m) and 690 (m) cm." 1 The nmr spectrum (CDC1 ) exhibited resonance signals at 67,38 (s , btoad, 6) and 65.31-53.31 (m, broad, 1). Anal. Calcd. for C o1 tt,,N £ 0_ (2 : 1 structure): C, 54.35; H, 3.45; 21 16 6 7 * N, 18.10. Found: C, 54.45; H, 3.87; N, 18.10. Copolymerization of PhTD and DVC at_ 60°In the same manner as followed for all 60° copolymerizations, a polymer tube was charged with. 0.500 g. (2.86 mmol.) of PhTD and 0.326 g. (2.86 mmol.) of DVC and 25 ml. of methylene chloride. After about 18 hours the resulting solution was clear and colorless, in contrast to all other reactions with PhTD when the solutions were yellow. Precipitation into hexane yielded a white solid, 0.608 g. (73.5% yield). The infrared and nmr spectra were identical to the room temperature trial. A molecular weight determination yielded a value of 1240. Attempte d copolymerization of PhTD with divinyl sulfone , DVS0 ? , at 60°A polymer tube was charged with 0.499 g. (2.84 mmol.) of PhTD, 0.320 g. (2.72 mmol.) of DVS0 2 and 0.004 g. (0.5 wt . %) of AIBN. The polymerization was carried out in the usual manner and after 24 hours at 60° 0.229 g. (29% yield) of a white solid were obtained. The infrared spectrum (KBr) was very similar to PhTD decomposition products except that some minor differences were recorded for the 1140 cm. and 1290-1260 cm. bands. The nmr spectrum (CDC1 ) gave resonance signals at 67.37 (s , broad with spike at 67.23, 7), 66.50 (m, broad, 1), 65.89 (m, broad, 1) and 54.50-6 3.80 (m, broad, 1). Anal . Calcd. for C 12 H 11 N 3°4 S ^ 1:1 structure ) " c > 49.20; H, 3.73; N, 14.31; S, 10,95. Found: C, 56.67; H, 3.91; N, 20.69; S, trace.

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107 Attempted co polymerizati on of_ PhTD with acry l onitrile , AN, at room temper ature -In the usual manner for room temperature polymerizations 0.501 g. (2.86 mmol.) of PhTD, 25 ml. of methylene chloride and 0.155 g. (2.88 mmol.) of AN were reacted for 42 hours. The solution remained red and precipitation yielded only 0.099 g. (15.1% yield) of a yellowwhite solid. The infrared spectrum was identical to the product from the PhTD horaopolymerization experiments, indicating no reaction with the AN. Attempted copolymerization of PhTD with AN at 60° The same procedure was used as followed in other 60° copolymerizations. The feed was 0.500 g. (2.66 mmol.) of PhTD, 0.151 g. (2.79 mmol.) of AN and 25 ml. of methylene chloride. The solution was still red when the contents of the tube were precipitated after six days at 60°. A tannishwhite solid (0.409 g., 63% yield) was obtained, whose infrared spectrun was identical to that of the preceding room temperature experiment, indicating that no reaction had occurred. Attempted copolymerizatio n of PhTD with AN at 60° with AIBNA polymer tube was charged with 0.500 g. (2.86 mmol.) of PhTD, 0.155 g. (2.88 mmol.) of AN, 0.003 g. (0.5 wt . %) of AIBN in 25 ml., of methylene chloride. A polymerization time of 24 hours was used and, on precipitation, 0.211 g. (31.8% yield) of a light yellow solid was obtained. The infrared spectrum (KBr) gave no absorbance that could be attributed to a nitrile. Some weak absorbance at 1610 cm." was the only apparent difference from PhTD decomposition products. The nmr spectrum (CDC1 3 ) gave resonance signals at 67.32 (s , broad, 5), 66.00-63.00 (very broad, approximately 2 or 3). Anal. Calcd. for C-q^N^ &:1 structure): C, 57.90; H, 3.50;

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103 N, 24.58. Found: C, 56.74; H, 3.64; N, 23.49. S pontaneous copolymer izat ion of_ N-vi nyl carbazole , NVC , and P hTD at room temperatureIn the usual manner for the 25° copolymerizations 0.502 g. (2.86 mmol.) of PhTD and 0.547 g. (2.33 mmol.) of NVC were reacted in 25 ml. of methylene chloride. The reaction discharged its red color within txro minutes after the comonomers were mixed. Precipitation yielded 0.899 g. (85.7% yield) of a white electrostatic solid. The infrared spectrum (KBr) gave the following absorbances: 3060 (m) , 1780 (m), 1725 (s), 1610 (m) , 1600 (m) , 1480 (m) , 1410 (s), 1320 (m) , 1255 (m), 1215 (m) , 1155 (m) , 1065 (w) , 1020 (w) , 740 (s), 720 (m) and 685 (m) cm. The nmr spectrum (CDC1~) gave one large broad resonance signal 68.50-65.80. Analysis of the polymer by gel permeation chromatography in dimethylformamide solvent resulted in a M of 54, 000, M a f j j w n of 21,000 and a molecular weight distribution. M /M , of 2.57. This ° w n value was calculated from a calibration of the column by a polystyrene standard. Anal . Calcd. for C 2 2 H 16 N 4°2 ^ 1:1 co P ol y mer ) : c > 71.25; H, 4.34; N, 15.21. Found: C, 71.59; H, 4.56; N, 15.43. Attempted hoaopolymerization of NVC by PhTDA solution of 1.659 g. (8.60 mmol.) of NVC dissolved in 50 ml. of methylene chloride was prepared and divided into two 25 ml. portions. To one portion, 0.5 mol. % of PhTD (0.004 g. in five ml. of methylene chloride) was added and stirred for 30 minutes. Precipitation into hexane yielded no solid formation. A control with no PhTD behaved similarly. ^.l Determi nation of rat e constants for PhTD-vinyl ether copolymerizations in various solvents

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109 The procedure used for determination of the rate constant in PhTD in its reaction with EVE in acetone solution is outlined below. It is an example of the experimental technique employed in determining the effect of solvents of various polarities on the rate of the PhTD-vinyl ether reactions and ccpolymerizations . PhTD (0.0176 g.) was weighed into a 10 ml. volumetric flask so that a 0.010 M solution resulted when brought to volume with dry spectro grade acetone. A 0.10 M solution of EVE was prepared by weighing 0.1800 g. of EVE into a 25 ml. volumetric flask and then bringing to volume. A 10-fold excess of EVE was used because of the difficulties encountered in weighing and transferring the EVE due to its high volatility. The extinction coefficient (e) and X were determined by fillJ max ing the sample cell with one ml. of the PhTD solution and one ml. of acetone and then scanning the 500-550 my region using a Beckman DK-2A spectrophotometer. A previous report in the literature pointed out a visible absorbance in this ranee. This determination of X was ° max made after setting a baseline of solvent versus solvent. The instrument was set at the determined A (523 my for acetonemax PhTD) and the sample cell was filled with one ml. of the PhTD solution and then one ml. of the EVE solution was added. The cell was shaken and immediately inserted into the spectrophotometer and the readings of absorbance commenced. The initial concentration of reactants was 0.05 M EVE and 0.005 M PhTD. A plot of the amount of PhTD consumed, calculated from the extinction coefficient, ver;.us time is shown in Fig. 10. The reaction was found to be first order in PhTD and the first order rate constant was determined by taking the slope of the plot of In [PhTD] /[PhTD] or A /A versus time as shown in Fig. 11.

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110 [-') O >; 4 o E o 0> E ::3 CO r.: O Q Z 0. r. O E o 10 (8 (minutss) r igure 10. Plot of consumption of PhTD versus time for EVE-PhTD in dioxane at 25 °C.

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Ill Time (minutes) Figure 11. Logarithmic plot of [PhTD] /[PhTD] or A /A versus time for EVE-PhTD in dioxane at 25 °8.

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112 7j_ Reactio ns of_ PhTD Ther mal decomposition of PhTD at^ 6Q°A polymer tube was sealed containing 0.500 g. (2.86 mmol.) of PhTD in 25 ml. of methylene chloride. After 24 hours the tube remained red with some white solid present. The white solid was removed by filtration and the red solution precipitated into hexane to yield 0.052 g. of a tan -white solid. The insoluble white crystalline solid failed to melt at 300°. From the following data it was assigned to structure 5_8. The infrared spectrum (KBr) was characterized by absorbances at 3060 (m) , 1735 (s) , 1755 (s) , 1625 (w) , 1500 (m), 1435 (s) , 1340 (m) , 1295 (w) , 1175 (s) , 1075 (m) , 1020 (m) , 925 (w), 780 (w), 750 (m) , 735 (m) , 725 (m) , 695 (m) and 650 (m) cm." 1 The mass spectrum (70 eV) gave the following fragments, m/e (rel. intensity) 322 (M+, 11), 321 (57), 150 (2), 149 (22), 146 (6), 145 (3), 120 (17), 119 (100), 91 (41), 90 (6), 84 (5), 77 (6), 70 (18), 65 (17), 64 (46), 63 (19), 52 (17), 51 (35), 50 (15) and 49 (11). Anal. Calcd. for C,,H, rt N,0, : C, 59.60; H, 3.11; N, 17.48. 16 10 4 4 Found: C, 59.60; H, 3.08; N, 17.48. The. tan-white solid which had been formed by precipitation into hexane yielded the following spectroscopic data. The infrared spectrum (KBr) gave absorbances at 3500 (m) , 1715 (s) , 1630 (w) , 1600 (w) , 1495 (m), 1420 (m) , 1280-1220 (w, broad), 760 (m) and 695 (m) cm." 1 The nmr spectrum (d, -acetone) yielded resonance signals at 67.50 (m, 6) and 64.48 (m, broad, 1). The molecular weight was determined to be 600. Anal. Calcd. for C o H c N o o (homopolymer of PhTD): C, 54.80; — O 5 J L H, 2.86; N, 24.00. Found: C, 54.47; H, 3.68; N, 21.52. Attempted free radical polyme rization of PhTD with AIBN at 60 °jThe previous reaction was repeated with 0.5 wt . % of AIBN present. Products

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113 identical in every respect to those of the previous reaction were obtained. Attempted radical polymerization of PhTD by p hotolysis of benzoyl peroxideA polymer tube was sealed in the usual manner with 0.501 g. (2.86 mmol.) of PhTD and 0.003 g. of benzoyl peroxide. The tube was inserted into an ethanol bath at -45° for nine hours while it was irradiated by a Hanovia lamp with ultraviolet radiation. The red color persisted in the solution and precipitation into hexane yielded 0.257 g. (51.4% yield) of a faint pink solid and a red filtrate. An infrared spectrum of the solid was identical to that of an authentic pure sample of the PhTD indicating no reaction had occurred. Reaction of PhTD with water-PhTD (0.598 g., 3.41 mmol.) dissolved in 25 ml. of dioxane was slowly added to 50 ml. of rapidly stirred water. Immediate reaction occurred resulting in a murky tan solution. The reaction was left to continue for one hour. The solids were removed by filtration and the filtrate was evaporated on the rotary evaporator at a temperature less than 40°. All the solids were extracted with methylene chloride and a small amount of insoluble white solid was obtained. The methylene chloride soluble portion was precipitated into hexane, redissolved and precipitated again and 0.392 g. (65.7% yield) of product was obtained. Its spectral characteristics were identical to other PhTD oligomeric products. The white solid, insoluble in methylene chloride, 0.046 g. (7.7% yield) was identical in all respects to an authentic sample of N, N'-diphenyl urea. Attempted homopolymerization of PhTD v^ith aniline -An Erlenmeyer flask was charged with 0.620 g. (3.54 mmol.) of PhTD dissolved in 30 ml. of methylene chloride. A solution of 0.0189 g. of aniline dissolved in

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114 10 ml. of methylene chloride was prepared. Two nils, of this solution were injected into the PhTD solution and after one hour a small aliquot gave no precipitate in hexane. Two additional mis. of the aniline solution were added and after 100 minutes no precipitate was noted on sampling and dropping into hexane. A total of five ml . more were added over the next 25 minutes and after 2.5 hours total reaction time precipitation into hexane yielded 0.133 g. (21.5% yield) of a brown precipitate. The molecular weight was determined to be 470. The infrared spectrum (KBr) was identical to the other PhTD oligomeric products. Attempted homopolymerization of PhTD with trie thy lamineInto an Erlenmeyer flask were introduced 0.620 g. (3.54 nmiol.) of PhTD dissolved in 25 ml. of methylene chloride. A triethylamine solution was prepared by dissolving 0.024 g. of triethylamine in 10 ml. of methylene chloride. Five ml. of the amine solution were injected via a syringe and the solution became turbid within five minutes. The reaction was allowed to continue for 17 hours at the ambient temperature. The mixture was filtered and then precipitated into hexane. The methylene chloride insoluble portion amounted to 0.059 g. (9.5% yield) and the methylene chloride soluble portion was 0.152 g. (24.5% yield) of a light tan material. The light tan material gave an infrared spectrum (KBr) identical to other PhTD oligomeric products. The infrared spectrum of the methylene chloride insoluble product was identical to the tetraone 58. Rea ction of PhTD with sodium cyanide in dimethy l formamideA sat84 urated solution of sodium cyanide in dimethylfornamide was prepared by dissolving 0.49 g. of the anhydrous salt in 50 ml. of dimethylformamide. A 50 ml. Erlenmeyer flask was then charged with 0.518 g.

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115 (2.96 mmol.) of PhTD and 20 ml. of dimethylformamide and 2 ml. of the salt solution were injected via a syringe. The reaction immediately turned dark and some gas evolution was noted. After about one hour of reaction the solution appeared black with a considerable amount of white solid present. After a total reaction of 2.5 hours the solid was removed by filtration and the filtrate precipitated by slow addition to ether. On filtration this yielded a brown solid. The initially insoluble solid 0.140 g. (27.1% yield) gave an infrared spectrum (KBr) identical to the tetraone 5_3. The brown solid 0.240 g. (46.3% yield) gave an infrared spectrum very similar to 58_. This solid was stirred with 25 ml. of acetone for 0.5 hours and the residue was much lighter in color with a dark brown acetone solution which on evaporation yielded a dark brown solid. The infrared spectrum of the dark brown solid was very similar to other PhTD oligomeric products. The acetone insoluble tan-white material was extracted on a Soxhlet extractor for several hours and seemed to exhibit partial solubility. Both the soluble and insoluble portions from the extraction had infrared spectra characteristic of the tetraone 58 . 8j_ Diels Alder Polymerization Study a^ Synt hesis of monomer Reactio n of ethyl carbaza te with 4 ,4 '-diphenylmethylene diisocyanate4,4'-diphenylmethane diisocyanate (11.9 g. , 0.047 mol.), freshly distilled before use, war dissolved in 30 ml. of benzene. This solution was dropped slowly into a solution cf the ethylcarbazate (9.95 g., 0.095 mol.) in 100 ml. of benzene. The isocyanate was added at room temperature and the rate of addition was controlled to maintain the temperature

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116 at 45° or below. After the addition was complete the voluminous white slurry was refluxed gently for two hours. The white solid was removed by vacuum filtration and then dried "in vacuo" to yield 21.2 g. (97.0% yield) of product with a m.p. 240-244° (with decomposition). A sample was purified for analysis by dissolving in dimethylformamide and precipitating into ether. The infrared spectrum (KBr) exhibited absorbances at 3380 (s , broad), 3305 (s , broad), 3025 (w) , 3000 (w) , 2940 (w), 1735 (s) , 1685 (s) , 1645 (s) , 1605 (s) , 1560 (s) , 1510 (s) , 1415 (m), 1370 (w) , 1315 (m) , 1305 (m) , 1225 (s), 1115 (w) , 1095 (w) , 1055 (m), 1035 (m) , 900 (w) , 850 (w) , 760 (m) and 615 (m) cm." 1 The nmr spectrum (d, -dimethyl sulfoxide) gave resonance signals at 68.77 (s, 2), 63.57 (s, 2), 67.91 (s, 2), 67.20 (q, 8), 64.05 (q, 4), 63.79 (s, 2), and 61.19 (t, 6). Anal . Calcd. for c 2 i H ?5 N 55-00; H, 5.54; N, 18.35. Found: C, 55.25; H, 5.77; N, 13.16. Preparation of 4 ,4 ' (4 , 4 ' -dipheiiy lmethylene) -diurazoleQn a steam bath, 5 g. (1.09 mmol) of the bis semicarbazide was added slowly to 25 ml. of 4 M potassium hydroxide. The addition, which was assisted with frequent swirling, took about one hour and the reaction was left on the steam bath for an additional hour. On removal from the steam bath it was noted that all the bis carbazide had gone into the basic solution except for a few white particles floating on the surface which were filtered. The solution was then cooled to 10-15° and 50% hydrochloric acid was t lowly added. On addition of >.ach drop, a polymeric like portion of solid would form which could be put back into solution with vigorous stirring. Attempted stirring with a magnetic stirring bar resulted in the precipitating solid adhering to it. (This problem

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117 was eliminated in later preparations by diluting the original volume of the solution to be acidified by about four fold.) As the reaction mixture was neutralized and just made acidic, a voluminous white precipitate resulted. This was removed by filtration and dried about 30 minutes on the water aspirator and then dried overnight at 70° "in vacuo". A quantitative yield of the bis urazole was formed. This product was recrystallized with water/5% methanol to yield white needles, m.p. 320° (decomposition). The infrared spectrum (KBr) was very similar to the 4-phenyl urazole and gave the following absorbances: 3410 (ra), 3320-2760 (s, broad), 1765 (m) , 1680 (s) , 1510 (s) , 1440 (s) , 1210 (m), 1120 (m), 1095 (m) , 1030 (w) , 1010 (w) , 865 (m) , 785 (m) , 760 (m) , 710 (m) , 690 (w) and 640 (m) cm." The nrar spectrum (d r dimethylsulf oxide) gave a broad resonance from 67.80-67.20 with a sharp spike at 67.38 equivalent to 12 protons and another resonance at 64.03 (s, 2). Anal . Calcd. for C^H^NgO : c, 55.75; H, 3.83; N, 22.90. Found: C, 55.73; H, 3.93; N, 22.94. Preparation of 4,4 '--(4 ,4 '-diphenylmethylene)-bis-l > 2 ,4-triazoline3,5-dioneThe bis urazole (2.30 g. , 6.25 mmol.) was placed into a 500 ml. Erlenmeyer flask with 25 g. of sodium sulfate and 250 ml. of methylene chloride. The solution was stirred in an ice-water bath and cooled to 5°. Dinitrogen tetroxide was bubbled slowly through the stirring slurry until a dark red color persisted (about 30 minutes). The sodium sulfate was removed by filtration and the dark red filtrate ,ras evaporated on a rotary evaporator using lukewarm water. A light pink solid was formed (1.80 g., 79.8% yield). -The solid had the following melting characteristics: 160-180° pink color changed to tan and up to 320° there was no

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118 decomposition. The infrared spectrum gave absorbances at 3620 (m) , 3060 (m), 2960 (w) , 2930 (w) , 2570 (w) , 2330 (w) , 2260 (w) , 1925 (w) , lyOO (m), 1875 (w), 1845 (m) , 1790 (s) , 1760 (s), 3 710 (m) , 1635 (m) , 1600 (w), 1510 (s), 1460 (m) , 1430 (m) , 1415 (m) , 1385 (s), 1300 (m) , 1180 (s), 1175 (s), 1150 (s), 1100 (w) , 1070 (w) , 1020 (m) , 955 (m) , 395 (m), 845 (m) , 810 (ra) , 790 (m) , 730 (s) , 715 (m) , 675 (s), 630 (m) , 625 (w) and 620 (m) cm. The mar spectrum (d, -acetone) yielded resonances at 67.48 (s , 8) and 54.18 (s, 2). Since the nmr spectrum indicated the bis triazoline dione to be free of impurities, it was used without further purification. b. Polymerization studies Copolym er izat ion of styrene and bis triazoline dione -A 100 ml. round-bottom flask was charged with 50 ml. of dimethylformamide and 1.30 g. (3.60 mmol.) of the bis triazoline dione. By means of a dropping funnel 0.374 g. (3.60 mmol.) of freshly distilled styrene, dissolved in 25 ml. of dimethylformamide, were added over a two hour period. The dark red color of the original solution lightened considerably over this time. After 7.5 hours no further color change was noted so the solution was warmed fur 10 minutes with an infrared lamp. No change appeared to be effected so the solution was divided into two equal parts. One portion was precipitated into ether yielding a light pink colored solid, which after washing with ether appeared tannish colored (solid A) and after drying weighed 0.493 g. The second portion of the original mixture was left stirring overnight and no significant change was noted. This was divided into two more portions. To the first was added 0.05 g. of styrene and after 10 minutes the residual red color was discharged to yellow. Precipitation

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119 into ether and drying yielded 0.306 g. (solid B) of a light tannish solid. The second portion was heated via a heating mantle to reflux for 15 minutes and during this period the solution turned to a dark brown color. Precipitation into ether resulted in 0.574 g. of a dark brown solid (solid C) . Solid A gave an infrared spectrum (KBr) with absorbances at 1780 (m), 1715 (s), 1605 (w) , 1515 (m) , 1495 (w) , 1415 (in), 1135 (w) , 1100 (w), 1020 (w), 815 (w) and 750 (w) era." 1 The nmr spectrum (d,D dimethylsulfoxide) yielded resonance signals at 68.40 (d, broad, 1), 57.37 (s, broad, 12), 65.67 (s, broad, 1), and 64.50-53.80 (m, broad, 4). A DSC thermogram recorded a decomposition temperature of 307°. The intrinsic viscosity in dimethylformamide at 28° was 0.12. Number average and weight average molecular weights, calculated from a gel permeation chromatogram, gave 36,000 and 120,000 respectively. The determination was made in dimethylformamide and was based on a calibration curve determined with standard polystyrene samples. The infrared spectra from solids B and C were identical to A. No other characterizations were done on B and C. Reaction of s tyrene and PhTDA 50 ml. Erlenmeyer flask was charged with 0.500 g. (2.86 mmol.) of PhTD, 0.151 g. (1.43 mmol.) of styrene and 25 ml. of methylene chloride. After five minutes the red color discharged to yellow which then went on to give a colorless solution. After 15 minutes a white precipitate began to form and at 45 minutes the reaction was stopped and the resulting solid was removed by filtration (solid A). The filtrate was stripped off on a rotary evaporator : and the resulting s.olid (solid B) remained soluble in methylene chloride, but on dissolution immediately began to precipitate.

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120 Solid A had a melting point of 250-52°. The infrared spectrum (KBr) gave absorbances at 3280 (m) , 1765 (m) , 1720 (s) , 1600 (w) , 1585 (w), 1495 (m), 1460 (w) , 1420 (m) , 1365 (w) , 1325 (w) , 1310 (w) , 1270 (w), 1250 (w), 1215 (w) , 1160 (w) , 1130 (m) , 1095 (w) , 1075 (w) , 1020 (w), S60 (w), 790 (w) , 750 (m) , 725 (m) , 685 (m) and 640 (w) cm." 1 The nmr spectrum (d,-dimethylsulfoxide) yielded resonances at 68.38 (d, 1), 67.35 and 67.38 (d and m respectively, 14), 65.70 (t, broad, 1) and 64.22 (m, 2). Anal. Calcd. for C o ,H 1 _,N.0. (2:1 adduct) : C, 63.48; H, 3.96; 24 17 4 4 ' ' N, 18.50. Found: C, 63.41; H, 4.01; N, 18.38. Solid B gave an infrared spectrum identical to solid A. It gave a melting point of 222-26°. No further analysis was performed. Reaction of sodium c yanide in dime thy If ormamide with 4 ,4'-(4,4 'diphenylmethylene)-bis-l,2 ,4-triazoline-3,5-dioneThe bis triazoline dione (0.188 g., 0.52 mmol.) was .dissolved in 25 ml. of dimethylformamide and then one ml. of concentrated sodium cyanide in dimethylformamide solution was injected via a syringe. A very slight gas evolution was noted and the only other change was loss of the red color to brown. Addition of another 0.5 ml. of the salt solution gave no significant change. The reaction was left for 24 hours and then precipitated into ether. A dark oily brown solid formed, which after washing with acetone and methylene chloride, yielded a light brown powder. The infrared spectrum (KBr) gave the following absorbances 2250 (w) , 1700 (m) , 1680 (m), 1650 (m) , 1510 (m) , 1370 (m) , 1170 (m) , 1C20 (w) and 750 (w) cm. ' No further effort was invested in characterizing this product.

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121 C. Syn theses Related to Tri ple Strand Model Comp ound Studies 1. Preparation of dienes 59 Preparation of 2 ,3-dimethyl-l ,3-butadiene sulfone , 82 -Into a 500 ml. autoclave, precooled in an isopropanol dry ice bath, were placed 60 ml. of methanol, 3.0 g. of hydroquinone, 78.0 g. (1.22 mol.) of sulfur dioxide and 100.0 g. (1.22 mol.) of 2 ,3-dimethyl-l, 3-butadiene. The autoclave was heated to 85° for four hours and the resulting solid was recrystallized from absolute methanol. Approximately 135 g. 59 (80% yield) of white crystals m.p. 134-37° (lit. m.p. 136-37°) were obtained. Recrystallization of the solid obtained on evaporation of the mother liquor raised the yield to approximately 90%. Preparation of 2 > 3-di-(bromomethyl)-l,3-butadiene sulfone , 83J" Into a 3 1. round-bottomed flask, 640 ml. of chloroform (reagent grade, washed 4 times with water and dried over magnesium sulfate and then distilled) were added. To the chloroform, 64.9 g. (0.443 mol.) of dimethylbutadiene sulfone, 82_, and 159.0 g. (0.886 mol.) of N-bromosuccinimide were added. Benzoyl peroxide (5.0 g., 0.021 mol.) was added as an initiator. The white slurry turned yellow and then amber during reflux and after 3-10 hours of reflux it returned to the original light yellow. The reaction mixture was allowed to cool and the resulting succinimide was removed by filtration. Most of the chloroform was removed on a rotary evaporator and the oily residue was refiltered to remove the remaining succinimide. Further evaporation on the rotary evaporator removed the remaining chloroform. An equal amount of 95% ethanol was added to the oily residue and the mixture was shaken vigorously for several rainutes (until the oily residue appeared as a white solid) . The product was placed in the refrigerator

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122 and shaken occasionally for 2 days. After filtering and recrystallizing from benzene 50.6 g. (37.6% yield) of slightly yellow crystals m.p. 120-21° (lit. * m.p. 124-125°) were obtained. Preparatio n of 2 ,3 -di-(acetoxymethyl)-l,3-butadiene sulfone , 847.0 g. (0.023 mol.) of the dibromosulfone, 7.6 g. (0.046 mol.) of silver acetate and 75 ml. of acetonitrile were placed into a 200 ml. roundbottomed flask equipped with a magnetic stirring bar and a reflux condenser. The acetonitrile was gently refluxed for three hours. At first, a white color was noted in the solution. This darkened during the reaction. The silver bromide formed was removed by filtration yielding a yellow filtrate. The acetonitrile was removed on a rotary evaporator leaving a brownish oil. About 50 ml. of chloroform were added to the oil, and the resulting solid, which seemed to be residual silver salts, was filtered. The filtrate was evaporated on the rotary evaporator and a yellowish white solid was obtained. The crude yield was 5.0 g. (86%). Recrystallization twice from absolute ethanol yielded 4.2 g. (72.5%) of white flaky crystals, m.p. 90-2°. The infrared spectrum (KBr) showed absorbance bands at 3040 (w) , 2995 (w), 2950 (w), 1720 (s), 1655 (w) , 1475 (w) , 1388 (m) , 1362 (s) , 1312 (s), 1255 (s), 1230 (s), 1185 (s) , 1139 (s), 1094 (m) , 1019 (s) , 960 (m). 920 (m), 884 (m) and 810 (w) cm." 1 The nmr spectrum (CDC1 ) exhibited resonance signals at 64.75 (s, broadened, 4), 53.86 (s , broadened, 4) and 62.03 (s , 6). Anal . Calcd. fov C 1Q H 4 fi S: C, 45.80; H, 5.35. Found: C, 45.70; H, 5.21. Pre paration of 2 , 3--di-(acetoxymethyl)-l,3-butadiene , 7_7_a-A 9 inch pyrolysis tube with a 14/35 ST female joint was charged with 4.0 g.

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123 (0.015 mol.) of the diacetoxy sulfone. The tube was connected by a double male 14/35, 14/20 ST joint to an adapter which led to a receiver flask immersed in an ice bath. Trie system was evacuated to less than 0.1 mm. and then the pyrolysis tube was inserted into a preheated Hoskins furnace at 200°. After a few minutes, liquid was seen collecting in the adapter leading to the receiver. The pyrolysis was stopped after one hour and 1.70 g. (56.5%) of the diene were obtained. After recrystallization from anhydrous ethyl ether, a white solid 58 m.p. 41-4° (lit. in. p. 43-4°) was observed. The infrared spectrum was identical to that reported. The nmr spectrum (CDC1 ) exhibited resonance signals at 55.35 (s, 4), 64.80 (s, 4) and 62.12 (s, 6). 58 Preparation of 2 ,3-di-(hydroxyme thyl)-l ,3-butadiene , 77b A 100 ml. round-bottomed flask was charged with 2.7 g. (0.014 mol.) of the diacetoxy diene, 1.9 g. (0.048 mol.) of sodium hydroxide and a fextf milligrams of diphenyl amine. The reaction flask was equipped with a condenser and was placed on a steam bath for 2.5 hours. On removal the solution was extracted 12 hours with ether on a continuous extractor. The ether was removed on a rotary evaporator and to the resulting oily residue 125 ml. of toluene were added. This solution was refluxed for three hours on a Dean-Stark trap to remove water. As the toluene was removed on a i otary evaporator, a white solid was formed which was removed by filtration to yield 1.4 g. (89.6%) 58 of product with m.p. 63-4.5° (lit. m.p. 63-4°). The infrared spectrum was identical, to that reported. The nar spectrum (CDC1_) exhibited resonance signals at 65.30 (s , 4), 54.37 (s, 4) and 51.88 (s, 2). 59 Preparation of is oprene sulfone , 85' -Isoprene (81.6 g. , 1.20 mol.),

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124 purified by distillation after washing twice with 100 ml. portions of 10% acidified ferrous ammonium sulfate, was placed into a one 1. autoclave that was precooled in a dry ice-isopropanol bath. To the isoprene 113 g. (1.77 mol.) of sulfur dioxide, 4.0 g. of hydroquinone and 88 ml. of methyl alcohol were added. The sealed autoclave was placed into a shielded autoclave reactor for 2.5 hours. Filtration and then work up of the mother liquor resulted in 175.9 g. of crude product. On recrystallization from methyl alcohol 150.0 g. of the 59 sulfone were obtained m.p. 62-64 (lit. m.p. 63-64°). 60 Preparation of 2-bromomethyl-l,3-butadiene sulfone , 86 -To 1.6 1. of chloroform (dried over anhydrous calcium chloride) in a three 1. round-bottomed flask, 132.0 g. (1.0 mol.) of isoprene sulfone, 178 g. (1.0 mol.) of N-bromosuccinimide and 12.0 g. (0.050 mol.) of benzoyl peroxide were added. The reaction was stirred and appeared as a white slurry at the start. The original preparation called for a reaction temperature of 75° which was not possible since chloroform boils at 61.2°. Vigorous boiling. and frothing started after several minutes at chloroform reflux and after two hours the reaction appeared dark red. The reaction was stopped after 24 hours tmd the solvent was removed on a rotary evaporator. Succinimide crystals were filtered off before all the solvent was evaporated. An equal amount of 95% ethyl alcohol was added and the flask was vigorously shaken for several minutes. The yellowish, cloudy mixture x^as left in the refrigerator for 24 hours and a crude product o c light, fluffy yellowishwhite solid was removed by filtration. Only 41.0 g. were obtained compared to 80.0 g. expected from the procedure. The product had a melting range of 74-78° versus lit. 78-84°. Care was taken in handling the solid because it was a strong lachryraator .

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125 Prepa ration of 2-brom.om ethyl -l,3-butadiene -The literature procedure was modified to the following method: 41.0 g. (0.195 mol.) of the halogenated isoprene sulfone were placed into a 500 ml. roundbottomed three-necked flask equipped with a Claisen head and a receiver immersed in an ice bath. The sulfone was heated via a heating mantle and 12.2 g. (43% yield) of a brownish liquid were collected between 35° and 35° at 10 mm. The infrared spectrum was as reported and an nmr spectrum indicated approximately 90% purity. This diene was used without further purification because it was a horrible lachrymator as reported! Preparation of 2-acetoxyme thyl-1 , 3-butadiene sulfone , 8714.3 g. (0.067 mol.) of the monobromo sulfone and 12.0 g. (0.072 mol.) of silver acetate were placed into a 250 ml. round-bottomed flask with 125 ml. of acetonitrile. The flask was equipped with a magnetic stirring bar and a reflux condenser. The reaction was refluxed for three hours with stirring. The solids were removed by filtration and the acetonitrile was removed on a rotary evaporator. Addition of chloroform to the dark oil resulted in the formation of some solid which when removed by filtration turned dark. On evaporation of the chloroform a yellow brown oil was obtained in 74% yield. This oil polymerized to a rubbery solid after a few hours; therefore it was used immediately after its formation. The infrared spectrum (neat, salt plates) had absorbances at 3030 (m) , 2980 (m) , 2940 (m) , 1735 (s) , 1655 (w), 1550 (w), 1+35 (m) , 1400 (m) , 1380 (my, 1305 (s), 1230 (s) , 1150 (m), 1125 (s), 1030 (m) , 970 (m) , 900 (m) , 780 (m) and 650 cm." 1 The nmr spectrum (CDC1 ) gave resonance signals at 66.06 (s, broad, 1), 64.69 (s, 2), 63.81 (s, 4) and 62.10 (s, 3).

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126 Ma 1. Calcd. for C H / S : C, 44.30; H, 5. '27. Found: C, 44.41; H, 5.03. Preparation of 2-acetoxymethyl-l,3-butadiene , 79aPyrolysis of the acetoxymethyl sulfone was accomplished by using a thermo-regulated horizontal Hoskins furnace. The pyrolysis was done at 200° at a pressure of 0.5-1.0 mm. A nine inch 14/35 ST pyrolysis tube was loosely packed with 6 mm. glass beads and these beads were then coated with 7.0 g. (0.037 mol.) of the sulfone to be pyrolyzed. The pyrolysis tube was connected to an adapter via a double male 14/35, 14/20 ST connector tube. The receiver was placed in a dry ice trap. The system was evacuated before its insertion into the preheated furnace. 3.90 g. (84% yield) of crude diene was collected which was purified by distillation at one ram. and 25°. The infrared characteristics were identical to those reported. 2 . Diels Alder Reactions o_f the Dienes with p-Benz o quinone Reaction of p-benzoquinone , 89 , with 2 , 3-di-(acetoxymethyl)1,3-butadien e in_ acetic anhydride . at room temperature-In a 50 ml. round-bottomed flask, the diacetoxymethyl diene (1.40 g. , 7.06 mmol.), quinone (1.0 g. , 9.25 mmol.) and 25 ml. of acetic anhydride were stirred together for 20 days. After this time 200 ml. of water were added to the solution and a brownish oil fell to the bottom of the flask. This oil was observed to crystallize overnight. A reddish-brown solid (0.5 g.) was obtained on filtration which was recrystallized from absolute ethanol to yield a reddish-brown solid m.p. 128-30°, which was identified as ^0_ by the following spectroscopic data. The infrared spectrum (KBr) exhibited the following absorbances : 2955 (w) , 1725 (s), 1655 (s), 1605 (m), 1595 (m) , 1435 (w) , 1455 (m) , 1425 (m) , 1410 (m) ,

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127 1380 (ra), 1340 (w) , 1303 (s) , 1235 (m) , 1245 (s) , 1225 (s) , 1140 (w) , 1120 (m), 1030 (s), 1000 (m) , 960 (m) , 925 (m) , 895 (w) , 840 (m) , 820 (m), 665 (ra) and 620 (m) cm." The nmr spectrum (CDC1 ) gave resonance signals at 66.75 (s , 2), 54.78 (s, 4), 63.23 (s, 4) and 62.12 (s, 6). Anal . Calcd. for c 16 \ 6 ° 6 : C, 63.20; H, 5.26. Found: C, 63.33; H, 5.02. Reaction of 89 w ith 77a in benzene at room temperatureA small flask was charged with 0.77 g. (3.89 mmol.) of the diene 77a, 0.76 g. (2.00 mmol.) of 89_ and 15 ml. of benzene. The flask was left at room temperature for 16 days. Removal of the solvent resulted in a brownish oily residue. An nmr spectrum gave resonance signals at 66.77 (s) , 56.75 (s), 66.67 (s) , 64.78 (s), 64.64 (s) , 63.23 (broad, with a sharp peak in middle), 52.43 (m, broad) and 62.05 (s) . This spectrum was indicative of a mixture of 90_ and the desired Diels Alder adduct 78a . The oily residue was dissolved in ethanol and immediately a brownishred precipitate was formed. Its spectral characteristics were identical to 90. Reaction of 89_ with 77a in ref luxing chloroform-A 10 ml . roundbottomed flask was charged with a few boiling chips, 0.25 g. (1.26 mmol.) of the diacetoxy diene 77a and 0.136 g. (1.26 mmol.) of quinone 89. These reactants were dissolved in eight ml. of chloroform and the reaction brought to reflux. The reaction was followed by nmr by removing an aliquot, blowing off a small portion of the chloroform with nitrogen and replacing it with CDC1„, and then taking an nmr spectrum. After 135 hours over 80% of the starting materials had beexi converted to desired Diels Alder adduct as exemplified by the

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128 disappearance of 65.34 and 54.80 singlet resonances of the diene and the formation of 66.68 (s) , 64.65 (s) , 63.27 (broad m) and 62.44 (broad) in the ratio of 2:4:2:4 respectively. All these peaks were similar to the known dibromo adduct 2]_. After 135 hours, the reaction was stopped and the solvent was removed and a yellow oil remained. Thin layer chromatography indicated that chloroform would remove remaining starting material and that ethyl acetate would move the desired compound. This was done on a silica gel column and a yellow oil was obtained which on redissolving in chloroform yielded a chloroform insoluble white crystalline substance m.p. 147-8°. This substance was believed to be 9JL. The infrared spectrum (KBr) gave absorbances at 3400 (s) , 1730 (s) , 1620 (m), 1485 (m), 1425 (m) , 1390 (m) , 1360 (m) , 1340 (m) , 1310 (s), 1290 (s), 1255 (s), 1235 (m) , 1195 (in) , 1145 (w) , 1110 (w) , 1025 (m) , 990 (m), 955 (m), 930 (m) , 895 (w) , 845 (w) , 800 (m) , 745 (m) , 695 (w) , 640 (w) and 610 (w) cm. The nmr spectrum (d, -acetone) gave resonance signals at 66.64 (s, 2), 64.48 (s, 4), 63.47 (s , 4), 52.88 (s , broad, 4) and 52.10 (covered by solvent) . Reacti on of 2 , 3-di( hyd rox y methyl) -1 , 3-butadiene , 77b , with 89 in ref luxing chloroformA 50 ml. round— bottomed flask was charged with 0.31 g. (2.73 mmol.) of the dihydroxy diene 77b, 10 ml. of chloroform and 0.293 g. (2.71 mmol.) of 89_. This mixture was allowed to reflux gently overnight. After 15 hours a brownish precipitate was formed and removed by filtration. On cooling, the filtrate yielded a fexj milligrams of unreacted diene. The brownish solid was extracted with boiling chloroform and a small amount of yellowish-white solid was obtained that gave a broad melting point around 150°. An nmr spectrum (d fi -

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129 dimethylsulfoxide) gave no indication of the desired adduct. Re action of 77b and 89_ in tetrahydro furan in a_ pressure bottle at 65°A pressure bottle was charged with 0.20 g. (1.76 mmol.) of the dihydroxy diene 77b and 0.19 g. (1.85 mmol.) of the quinone 89_. Tetrahydrofuran was added (10 ml.) and the bottle was flushed with nitrogen, sealed and placed into a 65° oil bath for 24 hours. The solvent was then removed on a rotary evaporator and a brownish-yellow oily like material was obtained which turned darker after a few minutes. The product was initially soluble in chloroform, but after a few minutes it precipitated out yielding a white solid which turned brown between 250° and 290° and did not melt or decompose below 325°. This solid was partially acetone soluble and the soluble portion gave an infrared spectrum (KBr) with absorbances at 3480-3100 (broad, s) , 2950-2860 (broad, m), 1670 (s), 1600 (w) , 1510 (m) , 1460 (m) , 1420 (m) , 1380 (m) , 1360 (m), 1280 (m) , 1250 (m) , 1210 (m) , 1190 (m) , 1140 (m) , 1095 (m) , 1040 (m), 1015 (m), 985 (m) , 950 (m) , 935 (m) and 710 (broad, m) cm. The nmr spectrum (d, -acetone) gave resonance signals at 66.70 (d, 1), 64.18 (s, broad, 1), 62.82 (s, 4), 52.52 (broad, 2). The few milligrams of acetone and chloroform insoluble material gave an infrared spectrum (KBr) with absorbances at 3350 (broad, s) , 2950-2890 (broad, m) , 1710 (s) , 1420 (m) , 1355 (w) , 1325 (w) , 1260 (m) , 1240 Cm), 1210 (m), 1170 (w) , 1140 (w) , 1085 (m) , 995 (m) and 795 (m) . Reaction of 2-b romomethy l-l , 3-butadiene , 94 , with 89 -Into a 200 ml. three-necked round-bottomed flask, 60 ml. of acetic anhydride, 11.0 g. (0.075 mol.) of the bromodiene and 8.0 g. (0.075 mol.) of 89_ were added. The reaction was left stirring at room temperature and after 36 hours a precipitate began to form. After 96 hours the reaction

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130 was stopped and the solid removed by filtration and 10.0 g. (57.7% yield) of a yellow solid were obtained. The material was readily recrystallized from benzene to give a light yellow powder m.p. 154-6°. This solid was identified as 9^5, the aromatized and acetylated Diels Alder adduct by the following spectral data. The infrared spectrum (KBr) showed absorbance bands at 2890-2800 (m, broad), 1750 (s) , 1365 (s), 1180-1110 (s, broad), 1015 (s), 940 (w) , 885 (m) and 815 (m) cm. The nmr spectrum gave resonance signals at 67.00 (s, 2), 66.05 (broad m, 1), 64.08 (broad s, 2), 63.30 (broad s, 2) and 52.30 (two s, 3 each). The mass spectrum (70 eV) gave the following fragments m/e (rel. intensity), 341 (1), 339 (M+, 1), 299 (6), 297 (6), 261 (12), 259 (12), 257 (12), 255 (30), 237 (6), 216 (15), 176 (100), 162 (9), 131 (9), 115 (9), 92 (9) and 43 (76). Anal . Calcd. for C H O.Br: C, 53.50; H, 4.40; Br, 23.60. Found: C, 52.57; H, 4.45; Br, 21.38. (sample appeared to decompose slightly before it was sent for analysis.) Reactio n of 2-acc t oxymethyl-l,3-butadiene with 89 at room temperature in benzeneA 50 ml. pear-shaped flask was charged with 1.0 g. (8.00 mmol.) of the acetoxymethyl diene 79a, 0.84 g. (7.70 mmol.) of recrystallized 89^ and then 10 ml. of benzene. The flask was flushed with dry nitrogen, stoppered and left for one week in the dark. At this time the solution was yellow and a greenish crystalline solid appeared in the bottom of the flask. After another weak the insoluble solid was clear and was removed by filtration. The nmr spectrum (d. -acetone) of this solid exhibited two equivalent sharp singlets at 66.80 and 66.68 (4 each) and a broad singlet at 52.83 (2). The melting point was 170-71°. Quinhydrone , m.p. 171°, fits all the characteristics of this

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131 product. After evaporation of the filtrate on a rotary evaporator, an oily residue was obtained which on extraction with petroleum ether yielded a yellow solid which darkened immediately on isolation. Thin layer chromatography yielded two spots and then column chromatography on silica gel with acetone/petroleum ether resulted in a yellow oil that darkened immediately. An infrared spectrum gave two prominent absorbances at 3500 cm. and 1600 cm. The nmr spectrum (CDC1.) gave resonance signals at 56.65 (m) , 55.75 (m) , 54.50 (2, broad singlets), 52.90 (s) and 52.10 (m) . The spectrum was not integrated and no further work was invested in isolation and identification of the product, Reaction of 79a with 89 in refluxing ethanolA small flask was charged with 0.25 g. (2.30 mmol.) of 89_, 10 ml. of absolute ethanol and 0.3 g. (2.40 mmol.) of the diene 79a.The flask was equipped with a condenser and then the reaction mixture was refluxed for 12 hours. After stopping, petroleum ether was added until a cloudy appearance persisted and then the flask was put aside in a freezer. A brown oil appeared in the bottom which was separated and chroma tographed on silica gel. Three fractions were taken and all were yellow-brownish oils. The middle fraction gave an infrared spectrum containing strong -OH absorbances at 3500 cm. and a broad carbonyl at 1710-1650 cm. The spectrum was practically identical to the one from the previous reaction in benzene. Since the product was not the desired Diels Alder adduct, it was not characterized further. Reaction of tetr acyanoet hylene with 79aA 25 ml. round-bottomed flask was charged with 0.6 g. (4.70 mmol.) of the diene and 0.6 g. (4.70 mmol.) of tetracyanoethylene. These reactants were dissolved in

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132 10 ml. of tetx'ahydrofuran and a yellow-brown complex of tetrahydrofuran and tetracyanoethylene was observed. The flask was stoppered and left for 24 hours. The solvent was removed on a rotary evaporator and a brownish oil was obtained, which when chloroform was added gave a light brown precipitate (unreacted tetracyanoethylene) and a yellow-brown solution. The chloroform was evaporated at reduced pressure to yield 1.1 g. (91.6% yield) of a crude brown solid. Two recrystallizations from 95% ethanol yielded a white crystalline solid m.p. 135—36°. The infrared spectrum (KBr) showed absorbances at 2990 (m) , 2905 (w) , 2340 (w), 2250 (w) , 1730 (s) , 1465 (m) , 1445 (m) , 1432 (m) , 1352 (m) , 1330 (w), 1312 (m), 1240 (s), 1220 (s), 1180 (m) , 1115 (m) , 1020 (a), 1000 (m), 905 (m), 870 (m) , 830 (m) , 790 (m) , 700 (w) , 650 (w) and 625 (w) cm. The nmr spectrum (CDClO gave resonance signals at 55.89 (m, 1), 64.51 (s, 2), 53.10 (s , 4) and 62.10 (s , 3). Anal . Calcd. for c 13 H 10 N / 2 : c > 61.40; H, 3.94; N, 22.02. Found: C, 61.20; H, 4.02; N, 22.30. 3. Preparation and reactions of 2~cy clohexene-l-one , 103 , and diazoq uinone, 104 Preparation cf q-bromocyclohexanone ' -In a two 1. three necked round -bottomed flask, 40.0 g. (0.41 mol.) of cyclohexanone, 73.0 g. (0.71 mol.) of N-bromosuccinimide and 2.0 g. of benzoyl peroxide were dissolved in 250 ml. of carbon tetrachloride and the resulting solution was reacted for one hour at 75°. The first observation was development of a yellow color which preceded a period of exothermicity and vigorous boiling during which a fluffy white solid formed on the sides of the flask. After the solid formed, the mixture was gently refluxed for the

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133 remainder of the hour. The mixture was cooled and the solid, which was water soluble, an indication that it was succinimide, was removed by filtration. The carbon tetrachloride was removed under reduced pressure. Further distillation at 65° and 2 mm. (reported 74°, 3 mm.) resulted in 38.5 g. (53% yield) of a colorless liquid which rapidly turned yellow on standing. The product was stored in the absence of light in a refrigerator and used as quickly as possible. Storage for three months resulted in a dark brown solid. Reaction of a-bromocyclohexanone with lith ium bromide in dimethylc o f ormamide A 500 ml. three -necked round-bottomed flask was set up with a nitrogen flush, a magnetic stir bar, a condenser and a thermometer. a-Bromocyclohexanone (35.0 g., 0.198 mol.), 200 ml. of dimethylformamide and 16.1 g. (0.185 mol.) of lithium bromide were introduced and the flask immersed in an oil bath at approximately 130°. The inside temperature rose to 120-130°. The reaction was followed by thin layer chromatography and after 18 hours the disappearance of starting materials was noted and the reaction stopped. To the dimethylformamide solution 200 ml. of water were added and then the aqueous solution was extracted three times with 75 ml. of ether. The ether extractions were combined and washed three times with 50 ml. of water. Evaporation of the ether yielded 10.9 g. of a yellow oily product with a phenolic odor. Vacuum distillation yielded only a few drops of a liquid with a phenolic odor and a viscous yellow oily residue which did not distill at 135° and two mmwas isolated. The viscous oil was soluble in carbon tetrachloride and chloroform. The infrared spectrum gave absorbances at 3400 (m, broad), 2950-2820 (s) , 1710-1650 (m, broad), 1440 (w), 1320 (w), 1085 (w) , 900 (w) and 740 (w) . The nmr spectrum

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134 gave an enormous multiplet centered at 52.00 and smaller multiplets at 65.70 and 66.70. No further work was done on this substance. Reaction of a-bromocyclohexanone with collidine Freshly distilled a-bromocyclohexanone (15.0 g. , 0.085 inol.) was placed into a 100 ml. round-bottomed flask equipped with a condenser. Collidine (15.0 g., 0.124 mol.) was added and the reaction vessel was immersed into a 180° oil bath for five minutes. During this period, the reaction mixture hissed and puffed up into the condenser as a solid. The solid residue was washed with 55 ml. of benzene and then the resulting slurry filtered. The solid was washed with 55 ml. of hot benzene and the combined filtrates were washed with a total of 60 ml. of 2 N hydrochloric acid twice. The benzene was dried over magnesium sulfate and then removed on a rotary evaporator. Vacuum distillation, 62-64.5°, 10 mm. (lit. 67 61-62°, 10 mm.) resulted in 4.7 g. (58.2% yield, lit. 42%) of the desired 103 . Autocla ve reaction of 2-cyclohexene-l-one , 103 , with 2-acetoxymeth yl-1 , 3-butadieneA 25 ml. autoclave was charged with 1.0 g. (8.00 nunol.) of the diene 79a and 1.0 g. (10.40 mmol.) of cyclohexenone, 103 . The autoclave was flashed with dry nitrogen, closed and then placed into an oil bath at 200° for 48 hours. The pressure rose to 100 psig. Upon cooling and opening, a waxy, gummy polymeric material was isolated. The material was soluble in acetone and chloroform. The infrared spectrum (KBr) gave absorbances at 2930 (s) , 1710 (s), 1450-1375 (m, broad), 1290 (ra) , 1245 (m) , 1000 (w) , 800 (w) and 750 (w) . An nmr spectrum (CDC1„) resulted in broad resonances centered at 67.00 and 61.70 in the respective relative intensities of 1:13.

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135 R eaction of 103 wi th 79a in a_ sea led t ube at room temperatureA tube prepared for sealing was charged with 1.0 g. of 103 (10.4 mmol.), 1.0 g. (8.00 mmol.) of the diene 79a and 10 ml. of benzene. The tube was evacuated and carried through a degassing cycle before sealing. After four days at room temperature the color had changed to a reddishbrown. The tube was opened and the solvent removed; an nmr spectrum of the oily residue indicated only starting materials. Aluminum chloride catalyzed reaction of 103 with 79a-To 3.02 g . (32.0 mmol.) of cyclohexenone in 10 ml. of methylene chloride, 3.5 g. of aluminum chloride were added. Much boiling and frothing occurred and the reaction turned reddish-brown. Then 4.00 g. (32.0 mmol.) of the diene 79a was added and the boiling was so vigorous that the mixture had to be cooled in an ice bath. After four hours the dark reddishbrown solution was poured over ice and the organic layer was separated in a separatory funnel. The methylene chloride was dried over magnesium sulfate and then removed on a rotary evaporator. An infrared spectrum of the crude reaction product gave a broad double carbonyl absorbance at 1680 and 1710 cm. The product was chromatographed on a silica gel column with benzene. An oil yielding only a 1705 cm. carbonyl absorbance was separated. Other infrared absorbances of this oil were at 2940 (m) , 2880 (m) , 1705 (s) , 1440 (m) , 1260 (m) , 1170 (w) , 1100 (w) , 1050 (w), 1020. (w) and 670 (m) cm." The nmr spectrum showed a broad multiplet centered at 62.20 (12), a singlet at 54.05 (2) and a multiplet at 55.85 (1). The mass spectrum indicated a halogen by its peak at m/e 198 and M+2 at m/e_ 200 which was 35% of M. One chlorine theoretically would give an isotope effect of 32.6%. The base peak at m/e corresponded to loss of a chlorine atom. From these data this product is believed to be 107.

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136 Reaction of_ 103 with 79a in a_ sealed t_ube at 190° A tube prepared for sealing was charged with 2.0 g. (16.0 mmol.) of the diene 79a , 1.53 g. (16.0 irariol . ) of the unsaturated cyclic ketone and a few milligrams of hydroquinone. The tube was sealed after degassing one time and placed into a 190° oil bath for three days. After cooling and opening 1.2 g. of a tan solid were isolated. This solid was purified by dissolving in chloroform and precipitating into pentane. At 210° it softened and began to turn brown and at 270° it decomposed. The infrared spectrum gave absorbances at 2920 (s), 2360 (m) , 1710 (m) , 1680 (m) , 1445 (m), 1370 (w) , 1229 (m) , 1150 (w) and 749 (w) cm." 1 The nmr spectrum (CDC1 ) exhibited resonance signals at 67.50-66.50 (broad, 1) and 63. 70-60. 75 (broad, 14). The substance was very similar, if not identical, to that isolated from the autoclave reaction. No further work was invested in this material. QC Prep aration of t-butyl hypochlorite -Fresh commercial Clorox bleach (500 ml.) was stirred in a one 1. three necked flask, which was placed into an ice bath and cooled to below 10°. A solution of t-butyl alcohol (37 ml., 0.39 mol.) and glacial acetic acid (24.5 ml., 0.43 mol.) was added quickly to the rapidly stirring bleach and the stirring was continued for three minutes. In a darkened hood, the mixture was poured into a one 1. separatory funnel. The lower clear aqueous layer was washed once with 50 ml. of 10% sodium carbonate solution and then 50 ml. of water. The product was dried over 2.0 g. of calcium sulfate 85 and filtered to yield 18.2 g. (43.2%, lit. 70-°>0%) of the hypochlorite which was stored in a brown glass stoppered bottle in the freezer. 54 Preparation of the potassium salt of ma.l eic acid hydrazi deMaleic acid hydrazide (112.0 g. , 1.0 mol.) was dissolved in a solution

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137 of 66.0 g. (1.16 mol.) of potassium hydroxide in 400 ml. of water by warming the mixture on a hot plate. The solution was then evaporated to dryness under vacuum. The product x^as dried for 96 hours at 97° in a vacuum oven. A total of 130.0 g. of the salt was obtained. 54 Preparation of diazoquinone , 1 04 -Into a 250 ml. three-necked round -bottomed flask equipped with a low temperature thermometer and a calcium chloride drying tube, 100 ml. of dry acetone were added along with a magnetic stir bar. The flask was placed into a dry ice acetone bath and cooled to -75°. 4.40 g. (0.40 mol.) of t-butyl hypochlorite were added and after stirring for several minutes 6.0 g. (0.04 mol.) of the potassium salt of maleic acid hydrazide were added. The mixture was left stirring at -77° for approximately 3.5 hours. The solution was observed to gradually turn to a green color. The solids v.ere filtered under nitrogen and through a dry ice jacketed coarse filter frit and the green filtrate was collected in the filter flask which was cooled to -77° in a dry ice acetone bath. Reaction of 104 with 2 ,3-di-(acetoxymethyl)-l,3-butadieneTo the just prepared diazoquinone, 1.5 g. (7.60 mmol.) of freshly prepared and recrystallized diacetoxy diene 77a were added after being dissolved and precooled to -77° in acetone. The green color did not disappear immediately upon addition of the diene. The mixture was left at -77° for 0.5 hours and then placed into a cold box at -55° for 12 hours. During this time the temperature slowly climbed to -10°. The flask was removed from the ."-.old box and 1.0 g. (.45 . 4% yieJd) of light yellow crystalline solid m.p. 142-44° was removed by filtration. The solid was recrystallized from absolute ethanol to give light yellow needle like crystals m.p. 148-49°. The infrared spectrum (KBr) gave absorbances at

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138 2960 (w), 1730 (s), 1675 (m) , 1650 (s) , 1595 (m) , 1480 (w) , 1445 (m) , 1425 (m), 1395 (m) , 1375 (m) , 1360 (m) , 1345 (m) , 1335 (m) , 1290 (m) , 1250 (s), 1235 (s), 1220 (s) , 1135 (ra) , 1030 (m) , 1000 (m) , 960 (m) , 945 (ra), 930 (ra) , 905 (m) , 850 (m) , 775 (m) , 670 (ra) , 620 (m) and 600 (m) cm." The nmr spectrum (CDC1 ) gave resonance signals at 56.92 (s , 2), 64.80 (s, 4), 54.57 (s, 4) and 62.09 (s, 6). Anal. Calcd. for C, ,H n ,N o 0, : C, 54.50; H, 5.20: N, 9.10. 14 16 2 6 Found: C, 54.35; H, 4.98; N, 9.01. Reaction of 104 with 2 , 3-di-(hydroxymethyl)-l , 3-butadieneThe procedure followed -,/as identical to the previous reaction in which the diacetoxy diene was used. 1.0 g. (52.0% yield) of cream colored fluffy solid was obtained with m.p. of 159-63°. Recrystallization from absolute ethanol yielded a yellowish cream colored solid m.p. 166-69°. The infrared spectrum (KBr) exhibited absorbances at 3480 (s), 3400 (s) , 3070 (ra), 3010 (w) , 2850 (w) , 1630 (s), 1585 (m) , 1440 (s) , 1350 (m) , 1275 (ra), 1260 (m) , 1235 (m) , 1155 (m) , 1110 (m) , 1030 (m) , 1015 (s) , 955 (w), 950 (m), 920 (w) , 860 (m) , 790 (ra) , 750 (w) , 695 (ral and 650 (m) cm. The nmr spectrum (d,-dimethylsulfoxide) gave resonance signals at 66.93 (s, 2), 64.51 (s , 4), 64.11 (s , 4) and 63.50 (broad, no accurate integration) . Anal. Calcd. for C 10 H 12 N 2°4 : C ' 53,50; H > 5 35 5 N > 12 -50. Found: C, 53.57; H, ^.50; N, 12.50. 4. Catalytic hydrogen at.ion of D_iels Alder adduc ts 72 Butadiene-89 aduuct -The catalytic hydrogenation of the Diels

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139 Alder adduct of 1,3-butadiene and p-benzoquinone was studied to obtain a model compound and to become familiarized with the hydrogenation equipment. The catalytic hydrogenation vessel was charged with 0.190 g. (1.17 mmol.) of the adduct, 40 ml. of ethyl acetate and then 0.08 g. of 5% Rh/C catalyst. After connecting to the apparatus, the flask was flushed five times with nitrogen and once with hydrogen before filling with hydrogen for the reaction. . This was the procedure used for all the hydrogenations at atmospheric pressure. After the theoretical uptake of hydrogen was observed, no further or additional hydrogen was absorbed. The catalyst was removed by filtration and the filtrate evaporated in 72 vacuo to yield 0.160 g. of a low melting solid m.p. 40-50°, (lit. 42.5-48.5°). 2 , 3-di-(acetoxymethyl)-l , 3-butadiene , 77a , and diazoquinone , 104 , at atmospheric pressure, ethyl acetate , 5_% Rh/CThe hydrogenation reactor was charged with 0.2227 g. (0.72 mmol.) of the adduct, 50 ml. of ethyl acetate and 0.094 g. of 5% Rh/C catalyst. The theoretical hydrogen uptake was 35.4 ml. and after two hours of reaction 36.1 ml. were absorbed. The catalyst was removed by filtration and the solvent removed on a rotary evaporator to yield a clear oil. An infrared spectrum (salt plates) of the oil showed 1735 cm. and 1675 cm. carbonyl absorbances. The runr spectrum was complex (d,-acetone) and gave ab— sorbances at £4. 50 -52.30 (complex m, 9), 62.10 (sharp s on top of solvent), 62.00-61.20 (m, 6) and 61. 20-60. 40 (m, 2). Column chromatography on silica gel resulted in a clear oil yielding an infrared spectrum identical to the original material except for new absorbances at 2250 and 920 cm. The reaction was repeated with similar results.

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140 2 , 3 -dl(hy drox ymethyl) -1 , 3-butadien e , 77b , and diazoguinone , 104 , atmospheric pressure , ethyl ac etate , 5% Rh/C -The reaction was carried out in the previous manner using 0.2055 g. (0.93 mmol.) of the adduct 108b and 0.112 g. of the 5% Rh/C catalyst in 50 ml. of ethyl acetate. Within 10 minutes exactly half of the theoretical uptake was observed and an additional several hours of reaction only gave a total of 89% of the theoretical uptake. From evaporation of the solvent a broad melting solid 132-37° was obtained which after recrystallization from absolute ethanol yielded a white solid m.p. 133-36°. This compound was identified as 114 from the following data. The infrared spectrum (KBr) gave absorbances at 3400 (s, broad), 2980-2850 (m, broad), 1650 (s , broad), 1440 (s, broad), 1320 (w) , 1265 (s) , 1230 (m) , 1200 (m) , 1175 (m) , 1160 (m), 1110 (w), 1030 (w) , 1045 (m) , 1005 (s) , 925 (m) , 905 (m) , 840 (m), 770 (w) , 740 (s), 695 (w) and 665 (m) era." 1 The nmr spectrum (CDCl„-d,-dimethylsulf oxide) gave resonances at 64.29 (s, 4), 54.10 (s , 4), 63.87 (s , broad, approximately 4) and 62.60 (s , 4). The mass spectrum gave a parent peak at m/e_ 226. 108b, atmospheric pressure , ethyl alcoh ol, 5% Rh/CThe same procedure was followed with 0.1627 g. (0.74 mmol.) of adduct, 0.089 g. of catalyst and 50 ml. of absolute ethanol as the reactor charge. The hydrogen uptake was 53.3 ml. compared to 35.4 ml. required for two double bonds. The uptake was identical for three equivalents. The product was a clear oil which gave an infrared spectrum with absorbances at 3410 (s, broad), 2980-2390 (m, broad), 2250 (m) , 169C-1650 (s , broad), 1450-1400 (s, broad), 1315 (m) , 1265 (m) , 1240 (m) , 1185 (m) , 1155 (m) , 1125 (m), 1105 (m), 1045(m) , 980 (m) , 925 (m) , 890 (m) , 875 (w) , 3 ; 840 (m) , 735 (m) and 650 (m) cm. The nmr spectrum (CDC1 ) possessed

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141 resonances at 64.20-63.20 (broad m, 6), 62.62 (s , two spikes, 4), 62.3261.60 (m, broad, 2) and 61. 40-60. 86 (septet, 2). No other analyses were performed. 108b, a tmospheric pressure , ethyl alcohol , 5% Pd/CThe reaction was performed almost exactly as the previous reaction except the 5% Pd/C catalyst was used. Almost three equivalents of hydrogen were taken up and the oil isolated gave an infrared spectrum identical to the previous product. The nmr spectrum was very similar with resonances at 64.6863.30 (m, broad, 7), 52.60 (s, 4) and 60.98 (sextet, 3). The mass spectrum gave m/e 211 as the parent peak and m/e 195 as the base peak. The oil was not characterized further. 108b , atmospheric pressure , ethyl a cetat e, 5% Pd/C-Using the same procedure, 0.0887 g. of 5% Pd/C and 50 ml. of ethyl acetate along with 0.2241 g. (1.02 mmol.) of 108b were put into the reactor and after 7.5 hours 90% of the theoretical absorption of hydrogen was measured. An infrared spectrum (salt plates, neat) of the resulting oil gave absorbances at 3500-3380 (s, broad), 2975-2880 (s, broad), 1690-1620 (s , broad), 1450-1400 (s, broad), 1315 (m) , 1270 (s) , 1235 (m) , 1190 (s), 1160 (m), 1105 (m), 1045 (s) , 985 (m) , 910 (w) , 890 (m) , 875 (m) , 840 (m) and 735 (m) cm. The nrnr spectrum (CDC1„) gave resonances at 64.20-63.20 (m, broad, 5), 62.60 (s , 4), 61.70 (s, 2) and 61. 10-50.77 (m, 2). The mass spectrum gave a parent peak at m/e 212. No further attempts were made to characterize this oil. 103b , 35 psi. , ethyl acetate , 5% Rh/CA Paar Hydrogenator was charged with 0.4766 g. (2.16 mmol.) of the dihydroxy adduct, 0.1728 g. of 5% Rh/C and 50 ml. of ethyl acetate. The system was flushed three times with hydrogen and .set at 35 psi and left rocking for 24 hours. On

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142 filtering the catalyst and evaporation of the solvent, an oil was obtained with some solid material. Recrystallization from ethanol yielded a white solid and a brown oil. The solid was crystalline with a m.p. of 151-54°. The infrared spectrum (KBr) gave the following absorbances: 3420 (s , broad), 2980 (m) , 2930 (m) , 2370 (m) , 1675 (s) , 1635 (s), 1440 Cm), 1420 (m) , 1310 (w) , 1260 (m) , 1225 (m) , 1180 (m) , 1155 (m), 1120 (w), 1105 (w) , 1040 (w) , 1000 (s) , 945 (w) , 910 (m) , 890 (m), 830 (m) , 730 (m) , 685 (w) and 645 (w) cm. -1 The nmr spectrum (CDC1~, with one drop of d,-dimethylsulf oxide) gave resonances at 64.31 and 64.13 (two overlapping broad singlets, 6), 62.65 (s, 4) and 6.1.75 (s , broad, 3). The mass spectrum (70 eV) gave the following major fragments: m/e 228, m/e 226, m/e_ 210 (base peak), m/e 194 and m/e_ 179. The brown oil gave an nmr spectrum (CDC1„) with resonance signals showing 64.50-63.30 (m, broad, 9), 62.60 (d, 5), 61.75 (d , 2), ol.OO (m, broad, 8). No further characterizations of the oil were attempted. 2 , 3-di(acetoxymethyl) -1 , 3-buta diene and p-benzoquinone , 90, 5% Rh/C, ethyl acetat e, atmospheric pressureIn a similar procedure to that used for the diazoquinone adducts, 0.2017 g. (0.66 mmol.) of 90 and 0.1046 g. of 5% Rh/C were added with 50 ml. of ethyl acetate to the reaction flask. The theoretical hydrogen uptake was 48.3 ml. and after five minutes 19 ml. were taken up and after two additional hours no further hydrogen uptake was noted. A brownish solid was obtained which was recrystallized from chloroform to give a white-silvery solid m.p. 143-45°. The infrared spectrum was identical to 91 . No further effort was exerted in characterization of this comDOund.

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143 5. S yntheses for attempted intramolecula r Die Is Ald er r eaction 29 Reaction of 89 with 2 , 3 -di(bromom e thy 1) -1 , 3-butadiene -Freshly prepared 2, 3-di-(bromomethyl) -1 , 3-butadiene (3.0 g., 0.013 mol.) and 4.0 g. (0.037 mol.) of p-benzoquinone were dissolved in 30 ml. of acetic anhydride. Over a five day period at room temperature a yellowishwhite precipitate appeared. The solid was removed by filtration and the product washed several times with water. The acetic anhydride filtrate was stirred with water and the resulting solid formed was combined with the original residue. After recrystallization from benzene 3.1 g. (74.5% yield) of the desired adduct m.p. 153-55° (lit. 29 m.p. 154-56°) were obtained. Reaction of the adduct of_ 89_ and 2 , 3-di(bromomethyl) -1 , 3-butadiene with zinc in dimethylforma mide -Zinc dust was purified by treating it three times with 5% hydrochloric acid. This was followed by washings with water, methyl alcohol and anhydrous ether. The zinc was then dried in a vacuum oven. To remove moisture, all glassware was flamed under a sweep of dry nitrogen. Into a 100 ml. three-necked round-bottomed flask, 2.5 g. (7.2 mmol.) of the dibrcmide adduct were added along with dimethylformamide (dried over molecular sieves for 24 hours). To this solution 2.0 g. of the purified zinc dust were added. After 24 hours of vigorous stirring, the reaction was stopped and the zinc dust removed by filtration. The dimethylformamide was added slowly to 400 ml. of water with stirring and a cloudy white precipitate formed which darkened on filtration. After isolation it was insoluble in both dimethylformamide and dimethylsulf oxide. The infrared spectrum (KBr) gave absorbances at 2900-2350 (m) , 1705 (s), 1665 (s) 5 1400 (m) , 1240 (m) ,

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144 1120 (m) , 975 (w) and 385 (w) cm. -1 From the insolubility and broad infrared bands, this solid was believed to be a crosslinked polymer. Zinc /dime thylformamide reaction in the_ presence of tetracyanoethy leneA predried 100 ml. three-necked round-bottomed flask was charged with 75 ml. of dry dimethylformamide, 2.3 g. (13.0 mmol.) of tetracyanoethylene, 3.1 g. (8.90 mmol.) of the dibromide adduct and 2.0 g. of treated zinc dust. On addition of the tetracyanoethylene to the dimethylformamide, a deep red color developed which persisted until the reaction was stopped after 48 hours. The excess zinc dust was removed by filtration and the filtrate was precipitated by addition of 200 ml. of water. The brownish solid isolated gave an infrared spectrum identical to tetracyanoethylene. The initial filtrate residue appeared to contain organic material along with the excess zinc. However, attempts to dissolve this material were unsuccessful. Seemingly, crosslinked polymeric material had been formed. Zinc /dime thylformamide reaction in presenc e of maleic anhydrideThe dibromide adduct (1.8 g. , 5.18 mmol.) was put into a dried 200 ml. three-necked flask with 75 ml. of dry dimethylformamide and 1.0 g. (10.2 mmol.) of freshly sublimed maleic anhydride. Zinc dust (2.0 g.) was added and the mixture stirred under a positive nitrogen pressure. The reaction turned to a reddish-yellow color and began to get cloudy during the first hour. After 24 hours, the reaction was stopped and the zinc was allowed to settle to the bottom and the suspended solid was removed by filtration and washed with water to remove zinc salts. The product was not soluble in organic solvents and was soluble in 50% potassium hydroxide. An infrared spectrum gave broad absorbances at

PAGE 154

145 1750 cm. and 1650 cm. Further attempts to work up and purify this product were not carried out. 6. Attempted preparation of 5 ,5 ,6 ,6-t etrasubstituted cyclohexadienes Preparation of coumalic acid -Malic acid, 200 g. (1-49 mol.) was placed into a two 1. round-bottomed flask with 170 ml. of concentrated sulfuric acid. To this suspension three 50 ml. portions of 30% fuming sulfuric acid were added at 45 minute intervals. The frothy mixture was put into a 90° water bath for two hours. During this time it was occasionally shaken and the color changed from cream to yellow to a dark brown. The solution was poured, with stirring, into 800 g. of crushed ice and a light yellow suspension was formed. On filtering and drying QC. over water 83.3 g. of the coumalic acid m.p. 185-90° (lit. m.p. 195-200°) were obtained. Recrystallization from 400 ml. of methanol and Norite gave 40.0 g. of a yellow powder m.p. 206-208° (lit. m.p. 206209°). Pre paration of a-pyrone Coumalic acid (79.5 g., 0.567 mol.) was charged into a 30 cm. x 10 cm. cylindrical flask which was inverted over a paddlewheel-powder stopcock. This was attached directly to a Vycor tube (60 cm. x 2.5 cm.) packed with approximately 15 g. of copper turnings. On top of the copper and above the heat zone a two cm. layer of six mm. Berl saddles was held in place by copper wire. The Vycor tube was run through a Hoskins Furnace (heat zone 32 cm.) and attached directly to a 500 ml. receiver which was immersed in ?n ice water bath. The receiver was connected to a two 1. gas surge reservoir followed by two dry ice traps and a highcapacity vacuum pump. After evacuation, the furnace was brought to 650° and the coumalic acid was dropped slowly

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146 through with the rate control such that the pressure remained below 10 mm. Occasional back release of air was found to loosen stoppage of the powdered acid at the stopcock. A black oily product was collected in the receiver. Vacuum distil76 lation at 75-76.5° and 1.3 mm. (lit. 83° , 2.6 mm.) yielded 30.0 g. 76 (54.8% yield, lit. 63.9%) of colorless product. The product was noted to become yellow in a few hours, even in the refrigerator. Reactions of q-py rone and tetracyanoethylen ea. Neat, room temperatureq-Pyrone (2.0 g. , 20.8 mmol.) was added to a 50 ml. three-necked round -bottomed flask and the flask was cooled to 5° in an ice water bath. Tetracyanoethylene (2.6 g. , 20.2 mmol.) was added and the mixture immediately turned a dark brownish-red color. After this the flask was removed from the bath and allowed to warm to room temperature and then it was left for an additional two hours. An nmr spectrum indicated only unreacted starting materials. b. Ref luxing te trahydrofuranTetrahydrofuran, 50 ml., and tetracyanoethylene (2.5 g, 20.0 mmol.) were mixed in a 100 ml. round -bottomed flask and a yellow colored solution resulted. To this solution 2.0 g. (20.3 mmol.) of a-pyrone were added and no noticeable color change was noted at room temperature for 24 hours. Ref luxing at 68-69° for an additional 24 hours resulted in a darkening of the yellow color. However an nmr spectrum of the reaction mixture indicated only unreacted starting materials. Cj_ Neat , 14C°, excess q-pyroneA 50 ml. r< und-bottomed threenecked flask was charged with 810 g. (83.5 mmol.) of q-pyrone and 6.0 g. (41.7 rnmol.) of tetracyanoethylene and then flushed with nitrogen. The excess q-pyrone was used to help put the tetracyanoethylene

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147 into solution and to guard against getting a "double" Diels Alder reaction. The temperature was gradually increased to 140° and was stirred smoothly for approximately two hours. After this time the mixture became black and tarry. This substance was extracted with chloroform and a brown oil was obtained which was identified as unreacted a-pyrone by its nmr spectrum. The black solid was not characterised further. d. Neat , 100° A small flask was charged with 1.5 g. (11.70 mmol.) of tetracyanoethylene and 3.5 g. (36.4 mmol.) of a-pyrone. After flushing with nitrogen the flask and contents were inserted into a 100° oil bath. After three hours a thin layer chromatogram of an aliquot indicated no reaction had occurred. After 24 hours the temperature was raised to 110° and a black solid appeared to start forming. The flask was removed from the oil bath and the black solid was rinsed with ether, which when evaporated gave a dark brown oil indicative of unreacted a-pyrone. The black solid was soluble in dimethylsulf oxide, but an nmr spectrum in this solvent gave no indication of the desired adduct. e. He fluxing xylene -Into a 100 ml. round-bottomed flask were introduced the following: 65 ml. of p-xylene, 6.0 g. (62.5 mmol.) of a-pyrone, 4.5 g. (35.1 mmol.) of tetracyanoethylene. The tetracyanoethylene formed a dark yellow-brown complex with the solvent. The solution was refluxed for 48 hours and after this time a black solid was filtered from the dark reddish-brown xylene. The xylene was removed in vacuo to yield large plate like brownish crystals which had a 4 m.p. of 197-99°, tetracyanoethylene (lit. m.p. 200°). These crystals were soluble in benzene with for-mation of a yellow color, a characteristic of tetracyanoethylen-e. From these observations it appeared no adduct was present and no further attempts to characterize these two

PAGE 157

solids were made. f . Refluxing bcnzene-Tetracyanoethylene (1.0 g. , 7.82 mmol.) and a-pyrone (1.0 g., 10.3 mmol.) were dissolved in 15 ml. of benzene and refluxed for 45 hours. A black solid was isolated which was not characterized. g. Refluxing tolueneTetracyanoethylene (1.0 g., 7.82 mmol.) and a-pyrone (1.0 g. , 10.3 mmol.) were refluxed in 15 ml. of toluene for 44 hours. A black solid tarry like substance was again isolated and was not further characterized. h. Tetrahydrofuran scaled tubeA heavy walled Pyrex tube was charged with 2.0 g. (14.6 mmol.) of freshly recrystallized tetracyanoethylene, 1.5 g. (15.6 mmol.) of recently distilled a-pyrone and 15 ml. of dry tetrahydrofuran. The tube was carried through a freeze-thaw cycle for degassing the contents and then sealed. The tube and its contents (dark yellow-brown) were placed into a 60° oil bath for 188 hours. On removal the contents had only darkened somewhat. An nmr analysis verified that no reaction had occurred. Reaction of a-pyrone and fumar onitril e-Fumaronitrile (1.0 g., 12.8 mmol.) and a-pyrone (1.0 g., 11.9 mmol.) were placed into 15 ml. of toluene and refluxed for four days. The reaction turned cloudy on cooling and a white solid was removed by filtration. Recrystallization from ethanol-ethyl acetate resulted. in a white crystalline solid m.p. 201-203°. The infrared spectrum (KBr) gave absorbances at 3100 (w) , 3045 (m), 2950 (m) , 2245 (m) , 2200 (w) , 1755 (s) ,. 1605 (w) , 1365 (s), 1345 (m), 1300 (w) , 1265 (m) , 1205 (m) , 1135 (m) , 1120 (m) , 1030 (m) , 1010 (m), 1000 (s), 980 (s) , 900 (m) , 300 (m) , 725 (ra) and 655 (m) cm." 1 Th e nmr spectrum (d, -acetone) gave resonance signals at 65.92

PAGE 158

149 (m, 2), 55.80 (m, 1), 64.08 (m, 2) and 5 3.63 (m, 1) . Anal. Calcd. for C n H,N„0„: C, 62.01; H, 3.45; N, 16.02. Found: y 6 i 2 C, 61.52; H, 3.62; N, 15.89. Reaction of p -benzoquinon e with g-pyroneA small flask was charged with p-benzoquinone O--0 g. , 9.25 mmol.) and a-pyrone (4.6 g., 54.6 mmol.), stoppered and set aside. After three days the reaction had darkened and another 1.0 g. of quinone was added. After two weeks, the insoluble portion was removed by filtration and the 1.2 g. of crude product were recrystallized from chloroform to yield 1.0 g. (56% yield) of light yellow crystals m.p. 149-52°. The infrared spectrum gave absorbances at 3050 (w) , 2950 (w) , 1750 (s) , 1655 (s), 1610 (m) , 13S0 (w) , 1355 (m), 1325 (m) , 1280 (m) , 1265 (m) , 1225 (w) , 1205 (w) , 1160 (ra) , 1115 (m) , 1100 (m) , 1060 (w) , 1005 (in) , 965 (m) , 940 (m) , 865 (m) , 825 (m), 805 (m) , 745 (w) , and 700 (m) cm." 1 The nmr spectrum (CDC1„) showed resonances at 66.82 (s , 2), 56.57 (t, 2), 65.69 (q, 1) and 63.60 (q, 2). Anal. Calcd. for C^HoO,: C, 64.70; H, 3.90. Found: C, 64.73; J.l o 4 H, 3.99. Reaction of_ a-p yrone with dimethyl maleic anhydrideDimethyl maleic anhydride (1.0 g. , 7.95 mmol.) and a-pyrone (1.0 g. , 11.9 mmol.) were refluxed for five days in 15 ml. of toluene. On removal of the toluene on a rotary evaporator a yellow liquid was obtained. An nmr spectrum indicated only starting materials. No further effort was put into the reaction. Reac tion of a-pyrone with tetraeth ylethylenetetracarboxylateThe tetra ester (1.0 g. , 3.16 mmol.) and a-pyrone Q..0 g., 11.9 mmol.) were refluxed for five days in 15 ml. of toluene. A yellowish-brown

PAGE 159

150 oil was obtained after the solvent was removed, 'a thin layer chromatogram indicated starting materials. The oil was set aside and after one year large crystals were noted formed in the bottom. No characterizations were attempted. R eaction of 2 , 3-dimethyl-l ,3 butadiene sulfone with bromine 80 A 250 ml. three-necked round-bottomed flask was charged with 20.0 g. (0.137 mol.) of the sulfone and 50 ml. of dry chloroform. Bromine, 21.8 g. (0.137 mol.), dissolved in 50 ml. of chloroform was added via a dropping funnel in small increments. A white solid (37.3 g., 89% Of) yield) was isolated m.p. 230-33° (lit. m.p. 215°). Prepara . t ion of. l^^dime thylthiophene-l , 1-dioxide -A 100 ml. three necked flask was equipped with a reflux condenser and drying tube with a nitrogen flush inlet. Into the flask were introduced 50 ml. of tetrahydrofuran (distilled from lithium aluminum hydride and stored over molecular sieves), 2.0 g. (33.0 mmol.) of sodium methoxide followed by 5.0 g. (1.63 mmol.) of the dibromide. Stirring was accomplished via a magnetic stirrer. A slight exothermicity was noted on the bromide addition. The reaction was heated at reflux with a fast nitrogen sweep for five hours. After cooling the residual solid was removed by filtration under a nitrogen flush. The solid was soluble in water, formed a precipitate on addition of silver nitrate and weighed 3.40 g. The theoretical amount of sodium bromide formed during the reaction was 3.38 g. Approximately 1.3 g. (45% yield) of crude productwere obtained m.p. 95-107°. Recrystallization from ethanol and petroleum ether gave a white solid m.p. 114-115° (lit. m.p. 114°). An nmr spectrum (CDC1 ) gave resonance signals at 66.32 (s, 2) and 62.06 (s, 6).

PAGE 160

151 Pr eparation of 2-hyd ro-3methylene4-meth ylthiophene-l , 1-dioxideUnder the identical conditions as the previous reaction, 9.7 g. (31.8 mmol.) of the dibromide, and 3.8 g. (36.3 mmol.) of sodium methoxide were reacted in 150 ml. of tetrahydrofuran. The reaction turned yellow and then very dark and on filtration sodium bromide was obtained. The black filtrate changed to yellow overnight and the yellow solid thus obtained, 3.3 g. , was recrystallized from ethanol-petroleum ether to 79 give a yellow solid m.p. 105-108° (lit. m.p. 110 ). The nmr spectrum (CDC1 ) gave resonance signals at £6.69 (s, 1), 65.60 (m, 1), 65.44 (m, 1), 64.00 (m, 2) and 62.10 (s, 3). Reaction of_ 3,4-dimethyl-thlophene-l,,l-dioxide with tetracyanoethyleneA 25 ml. pear-shaped flask was charged with 0.115 g. (0.80 mmol.) of the diene, 0.111 g. (0.89 mmol.) of tetracyanoethylene , a couple of carborundum chips and 10 ml. of dry tetrahydrofuran. The solution was refluxed for four days with the color darkening over this time. On evaporation of the tetrahydrofuran and redissolving the reaction mixture in chloroform the tetracyanoethylene was recovered quantitatively. Reaction o_f 3 ,4-dimethylthiophene-l, 1-di oxide with maleic anhydrideInto a 25 ml. pear-shaped flask were placed 0.143 g. (1.49 mmol.) of maleic anhydride and 0.222 g. (1.54 mmol.) of the diene. Toluene (10 ml.) was added and the mixture was brought to reflux. After a few hours small crystals appeared on the sides of the flask. The reaction was stopped after 24 hours and a few milligrams of the brownish crystals were obtained, m.p. 280°. Removal of the toluene gave a dark oil which gave an infrared spectrum featuring a double carbonyl anhydride and two bands at 1625 cm. and 1595 cm. " characteristic of a diene.

PAGE 161

152 The infrared spectrum (KBr) of the solid gave absorbances at 3005 (m) , 2990 (m), 2940 (m) , 2375 (w) , 1850 (s), 1730 (s), 1660 (m) , 1430 (m) , 1380 (w), 1310 (m), 1210 (s) , 1145 (m) , 1030 (m) , 1030 (m) , 900 (s) , 790 (m), 725 (m) and 670 (m) cm." 1 The nmr spectrum (d,-dimethylsulfoxide) gave resonance signals at o 63.55 (s, broad, 4), 63.20 (s, broad, 2) and 61.62 (s, 6). The mass spectrum (70eV) m/e (rel. intensity) gave fragments 277 (J-4), 276 (M+, 72), 249 (4), 248 (28), 176 (30), 175 (70), 174 (44), 159 (12), 131 (72), 130 (94), 117 (10), 115 (16), 107 (10), 106 (100), 105 (56), 99 (26), 92 (10) and 91 (82).

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REFERENCES CITED 1. B. T. Billis in Jan Hamer: "1,4-Cycloaddition Reactions," Academic Press, New York (1967), Ch. 6. 2. R. M. Joyce, U.S. Patent 2,507,718, May 16, 1950. 3. J. Sauer and B. Schroder, Angew. Chem. (IE), 4, 711 (1965). 4. W. J. Middleton, R. E. Heckert, and E. L. Little, J. Am. Chem. Soc, 80, 2783 (1958). 5. J. Sauer, Angew. Chem. (IE), 6_, 26 (1967). 6. G. B. Butler, 133rd ACS Meeting, San Francisco, California, April 1958. 7. K. C. Joyce, Ph.D. Dissertation, University of Florida, December 1966. 8. G. B. Butler and K. C. Joyce, J. Polyra. Sci., C 2_2, 45 (1968). 9. G. B. Butler and A. J. Sharpe, Jr., Polymer Preprints, 11, 42 (1970), 10. G. B. Butler, A. Crawshaw, and W. L. Miller, J. Am. Chem. Soc, . 80, 3615 (1958). 11. R. Huisgen, J. Jakob, W. Siegel, and A. Cadus, Ann., 590, 1 (1954). 12. W. H. Pirkle and J. C. Stickler, J. Am. Chem. Soc, 92, 7497 (1970). 13. J. K. Stille and L. D. Gotter, J. Polym. Sci., A-l, 7_, 2493 (1969). 14. R. J. Cotter and M. Matzner, "Ring Forming Polymerizations," Academic Press, New York (1969), p. 99. 15. W. J. Bailey, J. Economy, and M. E. Hermes, J. Org. Chem., 27, 3295 (1962). 16. , U.S. Patent 2,890,207, June 9, 1959. C.A. 53: 17572h. 17. J. K. Stille, Fortschr. Hochpolym. Forch.j3_, 43 (1961). 18. W. H. Carothers, Trans. Farad. Soc, 32_, 39 (1936). 19. J. K. Stille and L. Plummer, J. Org. Chem., 26_, 4026 (1961). 20. J. K. Stille and F. W. Harris, Macromolecules, 1_, 463 (1968). 153

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154 21. C. L. Segal, Ed., "High Temperature Polymers," Marcel Dekker, Inc., New York, N.Y. (1967). 22. F. L. Wallenberger, Angew. Chem., 76_, 484 (1964). 23. W. De Winter, Rev. Macromol. Chem. , 1_, 329 (1966). 24. M. M. Koton, J. Polym. Sci. , 52_, 97 (1961). 25. G. B. Butler and R. W. Stackman, J. Org. Chem., 25_, 1643 (1960). 26. (a) G. H. Fisher, Jr., Master of Science Thesis, University of Florida, 1968. (b) G. B. Butler, unpublished results. 27. G. B. Butler and G. C. Corfield, J. Macromol. Sci. -Chem., A5, 37 (1971). 28. K. Alder and M. Fremery, Tetrahedron, 14_, 190 (1961). 29. G. B. Butler and R. M. Ottenbrite, Tetrahedron Letters, 4373 (1967). 30. E. K. von Gustorf, D. V. White, B. Kim, D. Hess and J. Leitich, J. Org. Chem., 35, 1155 (1970). 31. H. Sato and T. Tsuruta, J. Macromol. Sci. -Chem., 2_, 295 (1970). 32. M. L. Brcy and P. Tarrant, J. Am. Chem. Soc, 7_9, 6533 (1967). 33. R. M. Silverstein and G. C. Bassler, "Spectrometric Identification of Organic Compounds," 2nd Ed., John Wiley and Sons, Inc., New York, (1967). 34. S. Tazuke and S. Okamura, J. Polym. Sci., AjJ^, 7_, 715 (1969). 35. N. G. Gay lord and A. Takahashi, J. Polym. Sci., B, 6^, 743 (1968). 36. F. F. Miller and H. Gilbert, Canadian Pat. 569,262, January 20, 1959. 37. N. C. Yang and Y. Gaoni, J. Am. Chem. Soc, 86_, 5023 (1964). 38. E. M. Kosower, Prog, in Phys . Org. Chem.j3_, 81 (1965). 39. G. B. Eutler and A. J. Sharpe, Jr., J. Polym. Sci., B, 9_, 125 (1971) 40. D. M. Jones and N. F. Wood, J. Chem. Soc, 5400 (1964). 41. M. Szwarc, "Carbanions , Living Polymers and Electron Transfer Processes," Inter science Publishers, New York (1968). 42. R. Gompper, Angew. Chem. (IE), 8_, 312 (1969).

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BIOGRAPHICAL SKETCH Sam Richard Turner was born October 17, 1942 in Madison, Tennessee. He graduated from DuPont High School in Old Hickory, Tennessee in June, 1960. In September 1960 he entered Tennessee Technological University in Cookeville, Tennessee and earned his Bachelor of Science degree, with honors, in chemistry in June 1964. While an undergraduate he held several student government positions including President of the Junior Class. He was also active in athletics, earning all conference honors in baseball and he captained the baseball team his senior year. He remained at Tennessee Tech through June 1966 and obtained the Master of Science degree in Chemistry. His research efforts were directed by Dr. Vernon R. Allen. In September 1966 he enrolled in the Graduate School of the University of Florida and has since continually pursued the degree of Doctor of Philosophy. He is a member of Alpha Chi Sigma, Kan pa Mu Epsilon and the American Chemical Society. On December 13, 1969 he married the former Pamela Sue Webb of Orlando, Florida. 157

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I certify that I have read this study aad that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. George B. Butler, Chairman Professor of Chemistry I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. James A. Deyrup Associate Professor of Chemistry I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. William R. Dolbier Assistant Professor of Chemistry

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I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. Martin T. Vala Assistant Professor of Chemistry I certify that I have read this study and that in my opinion it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. ~~t Robert B. Bennett Professor of Chemical Engineering This dissertation was submitted to the Dean of the College of Arts and Sciences and to the Graduate Council, and was accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy. June, 1971 Dean, College of Arts ana Sciences Dean, Graduate School

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UNIVERSITY OF FLORIDA 3 1262 08553 3254