Title: Mechanistic, model compound, and copolymerization studies of the 4-substituted-1,2, 4-triazoline-3,5-dione ring system
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Title: Mechanistic, model compound, and copolymerization studies of the 4-substituted-1,2, 4-triazoline-3,5-dione ring system
Physical Description: ix, 104 leaves. : illus. ; 28 cm.
Language: English
Creator: Wagener, Kenneth Boone, 1946-
Publication Date: 1973
Copyright Date: 1973
 Subjects
Subject: Polymers and polymerization   ( lcsh )
Chemistry thesis Ph. D
Dissertations, Academic -- Chemistry -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
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Thesis: Thesis -- University of Florida.
Bibliography: Bibliography: leaves 100-103.
General Note: Typescript.
General Note: Vita.
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Volume ID: VID00001
Source Institution: University of Florida
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MECHANISTIC, MODEL COMPOUND, AND COPOLYMERIZATION

STUDIES OF THE 4-SUBSTITUTED--1,2,4-TRIAZOLINE-

3.5-DIONE RING SYSTEM






By



KENNETH ECONE WAGLNER


A DISSEPTATIC'E PRESENTED TO T-E GRADUATE CCUNCIL OF

THE', UNi:VERSITY OF FLORIDA 7i PARTIAL FULTILL;:'E;T OF THE

FEQUJRE:iME1ITS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY






UNIVERSITY CF FLORIDA

1973
























This dissertation is dedicated to my brother Earl whose

accomplishments, both in our profession and in everyday life,

constantly set my personal goals.


















ACKNOWLEDGEMENTS


I would like to express my sincere appreciation for the encourage-

ment, guidance, and understanding provided by my research director,

Professor CGerge B. Butler. His presence during the course of this

work made the task both exciting and rewarding. I would also like

to acknowledge the members of my supervisory committee for their

comments and suggestions.

I wish to thank Dr. S.R. Turner, who initiated this research

project, for clearly defining the work to be done and for providing

valuable advice( during its completion. Discussions with Do. Chester

Wu were also illuminating.

The friendship provided by my fellow, grad-uare students in this

laboratory and by Vr. Ralph Spafford, Mr. Joe Wrobel and Mr. Bill

Mohle of Dr. !!. Vala's research group have made my stay at the

University of Florica most enjoyable. I am also indebted to Dr.

Richard Veazey for proofreading.the manuscript and Ms. Jimmie McLecd

for tying the dissertation.

I would like to acknowledge the Department of Chemistry for

providing the teaching assistantships, without which my attendance

would not have been possible.

Finally, ccnpleticn of the requirements for the degree would

have been extremely difficult without the love and understanding

of my wife, :gargaret.


iii


















TABLE OF CONTENTS


ACKr1OWLEC GE4ENTS . . . . . . . . . . .

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

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

ABSTRACT . . . . . . . . . . . . .

CHAPTER

I. IUTRODUCTIO; . . . . . . . . . .

A. General Background . . . . .......
B. Research Objectives . . . .

II. RESULTS AND DISCUSSION . . . . . ....

A. 1,LI-Dipole Copolymors . . . . . . .
E. The 1,4-Dipole Intr.amolecular Rearrangemnt .
C. Bis-Trtiazoline-dione Copclnymerizations . . .
D. Potential Aoplications . . . . . . .

III. EXPERIPLNTAL . . . . . . . . . .

A. General Information .......
B. Synthesis of 4-Phenyl-1,2,4-triazoline-3,5-dione
C. The 1,4-Dipole Copolymerizations .. . ....
D. The 1,4-Dipole Intramolecular Rearrangement .
E. Bis-Triazoline-dione Copolvyerizations ...

REFELRE CES CITED . . . . . . . .

BIOGRAPHICAL SKETCH . . . . . . . . . .


Page

iii

v

vi

vii

















LIST OF TABLES


Table Page

I. Summary of the 1,4-Dipole Copolymers Prepared by

Turner, Guilbault and Butler . . . . . . 14

II. Additional 1,4-Dipole Copolymiers . . . . .. 18

III. Molar Ratios for 1,4-Dipolc Copolymers . . ... .22

IV. Comonomer Nolar Ratios for Vinyl Benzoate

Copolymerizations .. ... . . . . . 28

V. Nuclear Magnotic Resonance Data for the Vinyl

Ester/PhTAD Reactions . . . . . . . .. 33

VI. Relative' Yields of Products . . . . . ... 3C

VII. Kinetic and Thermodynamic Data for the Vinyl

Esrer/PhTAD reactions . . . . . . . 39

VIII. Nuclear Magnetic Resonance Data for the Diels-Alder

Ene Model Compounds . . . . . . . . 57

IX. Nuclear Magnetic Resonance Data for the Diels-Alder

Ene Copolyners . . . . . .... ...... 58

X. Kinetic Data for the Vinyl Ester/PhTAD Reactions

Measured at Various Temoeratures . . . . .. 76


















LIST OF FIGURES


Figure Page

1 Aromatic Single: of 49 As It Opens to Copolyer . . 25

2 Comparison cf Nuclear Magnetic Resonance Spectra

of 51 and 34 . . . . . . . . ... . 32

3 Assignment of Proton Type to Nuclear Magnetic

Resonance Signals for 76 . . . . . . . 47

4 Nuclear IMagnetic Resonance Spectrum of 86 ...... 53

5 Nuclear Magnetic Resonance Spectrum of 87 . . . 54










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


MECHANISTIC, MODEL COMPOUNID, AND COPOLYMERIZATION
STUDIES OF THE 4-SUBSTI3UTED-1,2,4-TRIAZOLINE-
3,5-DIONE RING SYSTEM


By

Kenneth Boone Wagener

August, 1973


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


nWile the high reactivity of 4-substituted-l,2,4-triazoline-3,5-

diones has been studied extensively, little work has been done to

probe its utility in copolymerizations; thus, the major goals of this

research have been to investigate model compound reactions of

triazoline-diones that exhibit potential for copolymerizations, and

to study the copolymerizations themselves.

4-Phenyl-l,2,4-triazoline-3,5-dione (PhTAD) had been observed

to copolTyerize with vinyl ethers and other electron rich monomers

yielding one to one, alternating copolymers via a 1,4-dipole coupling

mechanism. The reactions of PhTAD with sever additional electron

rich comonomers were studied by this author, and the experimental data

obtained in formation of the low molecular weight copolyners allowed

refinement of the proposed mechanism.

PhTAD had also been observed to react with vinyl acetate to

yield l-formyl-2-acetyl-4-phenyl-l,2,4-triazoline-3,5-dione by means

of a 1,4-dipole intramolecular rearrangement. The mechanism of this

rearra!ngemen;t -as exhauctivelv studied by this author by reacting

vii











PhTAD with five new vinyl esters varying the size and electronic

stabilizing ability of the vinyl ester substituents. Steric blocking

decreased the relative yield of the trisubstituted triazoline-diones

producing substituted 1,3,5-triazabicyclo[3.2.0]hepta-2,4-diones by

closure of the 1,4-dipole, and copolyners by a mechanism similar to

that suggested for the PhTAD and vinyl ether copolymerizations.

Kinetic measurements were made on these reactions, and they were found

to be second order overall, first order in each reactant. In comparison

with the PhTAD/vinyl acetate reaction, electronic stabilization or

destabilization uf the l,'i-dipole respectively increased or decreased

the reaction rates of the other reactions. The energies and entropies

of activation were also calculated from the kinetic data, and these

quantities also lent additional support to the proposed mechanism.

Tn an attempt to employ the 1,4-dipole intramolecular rearrange-

ment as a means of propagation in copolymerization, divinyl and diiso-

propenyl adipate were reacted with bis-(p-3,5-dioxo-l,2,4-triazolin-4-

ylphenyl)-methane and a new bis-triazoline-dione synthesized by this

author, 1,6-hexane-bis-l,2,4-triazoline-3,5-dione. The copolymer-

izations produced approximately ten percent of the desired ccpolymer

and eighty percent of an insoluble solid which was not completely

characterized.

Previous studies suggested that the reaction of styrene and

bis-(p-3,5-dioxo-l,2,4--triazolin-4-ylphenyl)-methane yielded an

alternating, high molecular weight copolymer. The repeat unit was

thought to result from a Diels-Alder reaction followed by an ene

reaction. This copolymerization was reinvestigated, and the copolymer's

spectra were cormrared with the spectra of model compounds, which were










synthesized by the reaction of two moles of f'i'AD with styrene. The

comparison revealed that two types of repeat units existed in the

copolynmer, one ensuing a Diels-Alder reaction follo-wed by an one

reaction, the other resulttinr from tiwo consecutive Dials-Alder reactions.

The repec;L units were recent in .- two to one ratio, respectively.

Another Diels-Ald raieree copcly]er w .-s prepared by ti': reaction of

1,6-l.exar-bi s-l,2, -i.'a-zolnine-3 ,-dione with styrene, and was

characterized by conmpari.on of its spectra with those of analogous

model compounds. The i.c.:I(.e compounds were synthesized by reacting

two moles of 4-methyl- ,2 ,4-triawoline-3 ,5-dicna :ith stye sne. The

structure of the Di]ls-Alder ene model compound was exhaustively

charccteri :el including deuterium labelling studies.

















CHAPTER I

Introduction

A. General Background

4--Substituted- -,2,i4-triazoline-3,5-diones, 1, (TAD), a ring system

first synthesized in 1894 by Thiele,1 possess an extremely reactive

nitrogen double bond capable of a wide variety of reactions. The


0


/ H
o 0

i 2

compound is generated via oxidation of the corresponding urazole, 2,

a reaction which may be affected by oxidation with a number of

different reagents. Thielel used lead peroxide in cold, dilute

sulfuric acid to yield 4-phenyl-l,2,4-triazoline-3,5-dione, and

other chemists have had varying degrees of success with heavy metal
2
salts of the urazole in reaction with iodine, t-butyl hypochlorite

in acetone,3 lead tetraacetate in methylene chloride, bromine,5

fuming g nitric acid,6 and manganese dioxide, calcium hypochlorite or
7 8
N-bro:.ouccinnimide. Stickler and Pirkle reported the most effective

oxidation, however, accomplished by passing dinitrogen tetroxide gas

through a slurry of the urazole precursor in methylene chloride.

Purification is achieved by solvent evaporation and sublimation.











Although a number of triazoline-diones have been prepared in

this fashion, the parent compound, R=H, has never been isolated.

Stolle2 synthesized hut did not isolate it in 1912, and, more recently,
9
de Amezua, Lora-Tamayo, and Soto trapped it with several dienophiles

via the Diels-Alder reaction.

The chemistry of triazoline-diones with the exception of their

enhanced reactivity is similar to that of diethylazodicarboxylate
10-20
and other a-carbcnyl azo compounds.- TInvestigations into their

chemistry were begun in earnest early in the 1960's when Cookson,

Gilani, and Stevens3 published low temperature 4+2 cycloadditions of

4-phenyl-1,2 ,4-triazoline-3,5-dione, 3, (PhTAD) with cyclopentadiene

butadiene, and cycloheptatriene to yield 4, 5, and 6, respectively.






Y 6 5 66 6


4 5 6



This paper initiated an extensive amount of research concerning Diels-

Alder reactions of triazoline-diones.21-26 Other cycloadditions

include cbe reaction of PhTAD with tropone, azepin', and diazepine
27
which produced 1:1 adducts 7, 8, and 9, respectively.7 Evin and
S- OEt C02Et




'CEH5 C6H5 Y ICH5

7 8 9










08
Arnold8 have shown that isopyrazoles react with PhTAD affording

structures such as 10, which can be irradiated, resulting in loss of

nitrogen leading to 11. PhTAD then reacted further with 11 to give
29
the 2:1 adduct. 12.9 Addition to a cyclopropane ring fused in a



R ./' R


R


10 6H5
11
if---- IYN





CHS CH 5 0



12 13


five membered bicyclic system had been demonstrated previously by

reaction of PhTAD with bicyclc[2.1.0]-pentan-5-spiro-cyclopropane.3
31
Cookson, Gilani, and Stevens1 also reported a 2:1 adduct, 13, of

PhTAD with styrene, presumably the result of a double Diels-Alder

reaction. Other 2:1 adducts have been observed, such as 14, the
32
product of FhTAD and benzylidenecyclopropane and the 1:1 adduct of

PhTAD and oxonin, 15, which adds another FhTAD to give a 2:1 adduct
33, 34, 35
of unknown structure.

Other investigations of Diels-Alder cycloadditions include

reactions of PhTAD with 5-iodocyclopentadiene which gave 16,36 and

with polyenic azonines that produced compounds structured as 17.37
























5- 15


C H
I C6H5

(X=NCCOME)
(X=i-CO;ilE2)



16 6
16 17





As previously mentioned, triazoline-diones contain an extremely

reactive ring system, especially in cycloaddition conversions. Kinetic

studies have shown PhTAD to be one of the most powerful dienophiles

known to date.38 Ph-AD, in reaction with 2-chlcro-l,3-butadiene, was

found to react one thousand times faster than tetracyanoethylene and

some two thousand times faster than maleic anhydride.

Cyclcadditions of triazoline-dlones are not limited to Diels-Alder
39
reactions as recent studies show. Past and Chen39 observed a
2 2 2
((a 2+ )+ 2) cycloaddition of alkenylidenecyclopropanes, 18, and

PhTAD affording 19 and 20. Other cycloadditions of PhTAD and

alkenylidenecyclopropanes have been reported nore recently.40

trans-2,3-Dimethylmrethylenecyclopropane reacts with PhTAD at room

temp tur to yel he 2+2 cloadditin adduct, 2132 These
temperature to yield the 2+2 cycloaddition adduct, 21. These














R' -
Q~Z2----


R --/

R 0 + H65
R' R 0


authors have also observed cycloaddition reactions of substituted

vinyl cyclopropanes with PhTAD.41 Von Gustorf and coworkers42


CH3
H
H c
C3 6 5



found PhTAD to react in a 2t2 fashion with dihydro-1,4-dioxime

yielding 22, and with indene giving 23. The indene reaction pathway

was thought to be polar in nature, as the proposed 1,4-dipole was

trapped with water.


i -C6H5










The presence of an ionic reactive intermediate was also noted

in the addition of PhTAD to oxabenzonorbornadiene yielding 24, which

underwent a Wagner-Meerwein alkyl shift and ring closure to 25.43



0 1 N0

-C -H



24 25


Another type of reaction pathway available for triazolinediones
32
is the Diels-ene conversion (shown below). Past and Chen observed


S0 R








the ene product, 26, in the reaction of (4-phenylbutylidene)-cyclo-

propane and PhTAD. Pirkle and Stickler4 also investigated the ene

reaction and found PhTAD to be thirty thousand times more reactive

than ethylazodicarboxylate in reaction with a number of monoclefins

having a-hydrogens.

H /CH2C6 H5

RNR2N-
SC -CCH

K1 8










Cookson and coworkers45 have reported the oxidation of alcohols

to aldehydes and ketones with PhTAD. Substituted hydrazines also

have been oxidized by PhTAD affording an N-nitrene, which reacted

with a second PhTAD to yield an azimine, 27.46,47 Oxidation of

benzophenone hydrazone yielded an Ni-nitrene which reacted with PhTAD!

as before, but the azimine produced was unstable. Nitrogen was

evolved forming 28 which reacted further with benzophenone hydrazone

to give the azine, 29.4


(C, H ) C\
55 2

0N (C5H) 2-C=N-N=C-(C~5)2

C6H5
28 29

PhTAD has been used in the synthesis of prismane by initial

reaction with benzvalene, followed by basic hydrolysis and then

photolysis.49

PhTAD has also been reported to be a useful ligand in iridium

complexes.










B. Research Objectives

While the high reactivity of the triazoline-dione ring system

has been investigated extensively as a monofunctional molecule, few

attempts have been made to utilize this high reactivity as a propagating

mode in polymerization; thus, the main objectives of this study have

been:

1. To investigate nodel compound reactions of triazoline-diones

that exhibit potential for copolymerization.

2. To attempt the copolymerizations themselves.

Pirkle and Stickler5 homopolymerized 4-huryl-1,2,4-triazoline-

3,5-dione in chlorinated solvents by photolyzing the solution with

a visible light source (150 watt quartz-iodine tungsten lamp). The

polymer was thought to have a repeat unit 30 and a degree of polymer-

ization of twenty.




14-


IH9 n

30

Depolynerization of the polymer in solution resulted, however, upon

removal of the irradiating source regenerating 73% of the monomer;

for this reason, further studies of the homopolymers were not contem-

plated, even though the thermal stability could be enhanced by end-

capping the polyner with diazomethane.

Saville- has studied the reaction of bis-(p-3,5-dioxo-l,2,4-

triazolin-u-ylphenyi)-methane, 31, with a solution of natural rubber























and observed crosslinking due to the occurrence of the ene reaction;

however, the high reactivity of 31 prevented its use as a uniform

crosslinking agent of dry, unextended rubber.

Butler, Guilbault, and Turer53 investigated the reaction of

triazoline-diones with vinyl ethers and discovered the formation of

low molecular weight, alternating copolyners containing repeat units







nL n



32 33


32 and 33 via a 1,4-dipole coupling mechanism. When alkyl ketones

were used as solvents for the reaction, the 1,4-dipoles were trapped
54 55
yielding a new oxadiazine ring system.5 Guilbault, Turner and Butler5

also synthesized polymers having backbones of similar molecular

structure by reacting PhTAD with N-vinyl carbamates. Further studies

of these copolvmerizations were planned specifically to refine the

proposed mechanism and to characterize the new ccpolymers and has

been a primary objective of this study.











In addition, Turner56 found that, in reaction with vinyl

acetate, PhTAD yielded a 1,4-dipoie which underwent intramolecular

rearrangement to yield l-formyl-2-acetyl-4-phenyl-l,2,4-triazoline-

3,5-dione, 34. An exhaustive study of this rearrangement was proposed,



HJ 'CH29-p-- H
/ H3

C H5
34


and reactions were planned using the rearrangement as a propagation

mode for copolymerization.

In the past, few Diels-Aider reactions have been used successfully

in polymerizations. 2-Vinylbutadiene, 35, undergoes self-addition

yielding an insoluble polymer. a,a'-Bis(cyclopentadienyl)p-xylene,

36, also undergoes self-addition in benzene yielding soluble polymers.57










n CH2=CH-C =CH2 2
CH 2=C
1 n

















n -H2- Q CC CHC



36


Step-growth copolymerizations of a bidiene with a bidienophile have

also been studied, such as the copolymerizations of several bidienes,

37, prepared from 2-hydroxymethylbutadiene, with N,N'-bis-(maleimides),

38, yielding copolymers of low intrinsic viscosity.58 The major



H2CH0 R[ K


CH +
2 0 2

37 38






CFCH20ROCH



n


drawback of most of these and other Diels-Alder polymerizations is

the fact that the yields and reaction conversions are inherently low.

Propagations by the Diels-Alder reaction can be classified as step-

growth mechanism, addition polymerizations; thus, molecular weights











are governed by the Carothers Equation (Equation 1). The average

degree of polymerization, DP, is a function of the reaction conversion,

p, and a conversion of 98% or greater is necessary for high molecular

weights.

Equation 1 DP = --


This requirement severely limits polymerization by the Diels-Alder

reaction. Attempts to increase conversion by raising the temperature

usually initiates a retro-Diels-Alder reaction, which results in

depolymerization. Since triazoline-diones are extremely reactive

dienophiles, it was thought that their use might result in high

conversions at relatively low reaction temperatures; thus, model

compound reactions and copolyrerizations were planned with the

objective of obtaining high molecular weight copolymers.

















CHAPTER II

Results and Discussion

A. 1,4-Dipole Copolymers

Review of previous results

Recently G.3. Butler, L.J. Guilbault, and S.R. Turner prepared

low molecular weight, alternating copolymers by the reaction of

4-substituted-l,2,4-triazoline-3 ,5-diones with vinyl monomers

containing electron donating groups adjacent to the double bond.53

These copolymers, listed in Table I, were described as containing

both repeat units 39 and 40, with 39 predominating when the electron





^-H CH --CH-CH'



R n 0 k n


39 40

donating ability of "E" was large. Repeat unit 40 identified by
-i
its strong infrared band at 1610 cm. due to the -C=N- linkage -

isonerized to 39 if heated or allowed to stand in solution. The

copolymers were soluble in most organic solvents, and were white,

odorless solids softening around 100. Yields were generally greater

than 80%. Catalytic hydrogenation of the divinyl ether/PhTAD

copolymer yielded a copolymer having the same nuclear magnetic















Table I 59

Sumnary of the 1,4-Dipole Copolymers

Prepared by Turner, Guilbault and Butlera


Comonomer Product 1 (Range)c
n

Divinyl Ether 1:1 copolymer (450-3100)

Ethyl Vinyl Ether 1:1 copolymer (410-3900)

Isobutyl Vinyl Ether 1:1 copolymer

Civiny] Carbonate 2:1 copolymer 1240

N-Vinyl Carbazole 1:1 copolymer (3000-5000)d

N-Vinyl Carbamate 1:1 copolymer 4400



Copolymerizations carried out in methylene chloride. Other solvents

were also studied.

Analysis by vapor pressure osmometry.

"Large number of samples prepared.

dAnalysis by gel permeation chromatography, S.R. Turner, Private

Communication, Xerox Corporation.










resonance chemical shifts as observed for the ethyl protons in the

ethyl vinyl ether/PhTAD copolymers.

The copolymerizations occurred spontaneously at room temperature

and were thought to proceed via coupling of a dipolar intermediate

(Scheme I). When the copolymerizations of PhTAD and ethyl vinyl

ether (EVE), divinyl ether (DVE), or isobutyl vinyl ether (IVE) were

completed using acetone as the solvent, a small percentage of the

proposed 1,4-dipole was trapped by the carbonyl yielding the corres-

ponding tetrahydrooxadiazines.


SCHEME I


0=1 =
R
,R -


+


:E,--R'







R


1,4-Dipole couplii


R'












-g











The 1,4-dipole copolymers were either formed exclusively or

as a mixture of copolymer and the corresponding 1,3,5-triazabicyclo-

[3.2.0]hepta-2,4-dione (commonly referred to as a 1,2-diazetidine),

depending upon the electron donating ability of the group adjacent

to the vinyl group of the vinyl comonomer. For example, the reaction

of PhTAD and ethyl vinyl ether afforded copolymer exclusively,

while the divinvi ether/PhTAD reaction yielded a mixture of the

1,2-diazetidine and copolymer. These results were attributed to

the greater stability of the ethyl vinyl ether/PhTAD 1,4-dipole

relative to the divinyl ether/PhTAD 1,L-dipole, whose stability was

decreased (and reactivity increased) by the electron withdrawing

vinyl group. The divinyl ether/PhTAD 1,2-diazetidine could be

converted to copolymer by heating a methylene chloride solution

to 60.

The N-vinyl carbamate/PhTAD reaction55 also yielded a 1,2-

diazetidine along with an alternating 1:1 copolymer; however, the

1,2-diazetidine was thermally stable, even at 600. The ring could

be opened to copolymer chemically by hydrolyzing the amide function

to the amine with gaseous HBr, after which polymerization occurred.

Three possible methods of termination which would lead to

low molecular weight copolymers were proposed. Since the propagating

species were thought to be ionic, impurities such as water could

easily have terminated the chain. Dipolar coupling would also

terminate the chain leading to a nacrocycle. Thirdly, disproportion-

ation between two chains would lead to a vinyl ether end group and

a urazole end group concluding growth of both chains.











Preparation of new copolyners

Further studies of 1,4-dipole copolymers were completed by this

author, and Table II describes additional copolyrers resulting from

the reaction of vinyl monomers and PhTAD.

Ecuimolar quantities of 1,2-dimethoxyethylene (80% trans) and

PhTAD reacted spontaneously at room temperature resulting in an

80% yield of a white, odorless solid. Spectral and elemental analysis

indicated the solid to be polymeric in nature with repeat units 42

and 43 present, 43 predcminating as confirmed by the strong 1610 cm.-1

band in the infrared spectrum. Further analysis of the reaction

revealed a 12% yield of a white, odorless adduct whose elemental




OCHO

O I OC H O



I n H5 n
C6H5

42 43

and nuclear magnetic resonance analysis indicated the presence

of a 1,2-diazetidine ring structure. Upon heating a solution of

the adduct in tetrahydrofuran to 600, the 1,2-diazetidine ring

apparently opened to a low molecular weight, alternating ccpolymer.

Analysis as before showed the predominating repeat unit to be 43.

p-2-Vinyl.oxyethoxytoluene reacted rapidly with PhTAD giving

an 85% yield of a crystalline, white copolymer of low molecular

weight. Nuclear magnetic resonance and infrared analysis indicated

the predomirnance of repeat unit 44, since the 1610 cm.-1 band was

















Table II

Additional 1,4-Dipole Copolymers


Product


1,2-Dimethoxyethylene
(80% trans)

p-2-Vinyloxyethoxy
toluene

N-Vinyl-2-pyrrclidone

N-Vinylsuccinimide

Vinyl Benzoate

Vinyl Isobutyrate

Vinyl Pivalate


1:1 copolymer


1:1 copolymer


1:1 copolymer

1:1 copolymer

1:1 copolymnere

* 1:1 copolymere

* 1:1 copolymer


aMethylene chloride used as solvent.

bAnalysis by vapor pressure osmometry.

Copolymerizations at 600; > 1:1 indicates larger percentage of PhTAD.


Comonomer


b (Range)
g (Range)
n


1860


1430


1100

1400

1200

1250

(1230-1500)


_~_~











very weak in the infrared spectrum.

The reactions of l-vinyl-2-pyrrolidone and N-vinyl succinimide

with PhTAD were both rapid, room temperature copolymerizations each

yielding approximately 85% 1:1 alternating copolymers, the former

mostly structured as 45, the latter as 46.






0 0 \


2 -


S45



Cli

44 C6H5

46

Since the 1610 cm.- band was very weak for both copolymers, the

repeat unit containing the -C=N- linkage was thought to be present

only in low percentages.

Contrary to the PhTAD reactions of vinyl ethers and compounds

having vinylic groups adjacent to amide-like nitrogens, vinyl esters

reacted very slowly at room temperature in one case, not at all -

and in some instances, adducts resulted exclusive of copolymer formation.

While the details of adduct formation are discussed in section "B"

of this chapter, their copolymers are described here in comparison

with the other 1,4-dipole copolymers. Vinyl benzoate, vinyl pivalate,











and vinyl isobuzyrate formed low molecular weight copolymers in

yields of 87%, 16%, and 15%, respectively, in addition to adduct

formation, while isopropenyl acetate and vinyl chloroacetate afforded

adducts only. Due to the low reactivity of the vinyl esters, the

reactions were carried out at 60 in a sealed tube. Even at this

temperature, vinyl trifluoroacetate failed to react. Although

elemental analysis of the copolymers disclosed a larger percentage

of PhTAD present, indicating the copolymers were no longer alternating,

the infrared and nuclear magnetic resonance spectra were similar to

the spectra of the 1:1 alternating copolymers; thus it was thought

that the repeated units in each case were similar to those previously

reported.


Refinement of the mechanism proposed by Turner, Butler, and Guilbault

In an attempt to more closely compare the new results with those

already published by Turner, Guilbault, and Butler, the following

equation* was used to determine the molar ratio of comonomers in

the 1,4-dipole ccpolymers:

nl E2M2 AM2
Equation 2 E M1 E
n2 EAM1 IM1

M1 and M2 are the molecular weights of PhTAD and vinyl ester,

respectively; El and E2 represent the percent of the element present

(C, H, or N) in PhTAD and vinyl ester, and EA represents the percent

element (C, H, or N) obtained from the elemental analysis. The

comonomer ratio of PhTAD to vinyl ester in the copolymer, nl/n2'


* Derived by Mr. J. Wrobel, Department of Chemistry, University of
Florida.











was calculated for each carbon, hydrogen and nitrogen analysis, and

the average value, nl/n2, is reported in Table III. The products

of reactions 1 through 8 are most likely formed via an identical

intermediate, which probably differs in some fashion from the

intermediate involved in reactions 9 through 12. Experimental

evidence has shown a 1,4-dipole to be involved in both types of
60
copolymers since both dipoles have been trapped by acetone;

however, the reactivity of the 1,4-dipole is apparently influenced

by the stabilizing ability of the electron pair of the atom adjacent

to the positive charge.

With the above thoughts in mind, a.modified mechanism for

the Turner et al. reaction of PhTAD and ethyl vinyl ether is

proposed in Scheme II, which can be taken as a specific example

for the general formation of 1:1 alternating copolymers. Ethyl

vinyl ether reacts with PhTAD generating the initial 1,4-dipole,

47, which can either couple with another nearby 1,4-dipole or close

to the 1,2-diazetidine, 48. The 1,2-diazetidine can open to generate

low concentrations of 1,4-dipole to "feed" the 1,4-dipole coupling

process leading to copolymer. The ease of opening of the 1,2-

diazetidine is affected by the electron pair adjacent to the positive

center; in this case, the ring opening is facile under reaction

conditions. The overall reaction of the 1,4-dipole is depicted

in the energy diagram below, demonstrating the 1,2-diazetidine to

be the kinetically favored product of the reaction and the copolymer,

the thermodynamically stable product.

At room temperature, the 1,2-diazetidine rapidly opens to form

copolymer; however, if the reaction temperature is lowered to -9,














Table III

Molar Ratios for 1,4-Dipole Copolymersa


Reaction No.


Comonomer


Reaction Temperature


1 Divinyl Ether RT

2 Divinyl Ether 60

3 Ethyl Vinyl Ether RT

4 1,2-Dimethoxyethylene RT

5 p-2-vinyloxyethoxytoluene RT

6 N-vinyl-2-pyrrolidone RT

7 N-vinylsuccinimide RT

8 N-vinyl Carbazole RT

9 Vinyl Benzoate 500

10 Vinyl Benzoate RT

11 Vinyl Pivalatec 600

12 Vinyl Isohutyrate 60


nl/n2

1.01/1

1.03/1

1.07/1

0.975/1

1.00/1

i/1b

1.08/1

0.910/1

1.32/1

1.27/1

1.72/1

2.01/1


a
Copolyimerizations 1, 2, 3, and,8 were completed by Turner, Guilbault,

and Butler.

bCarbon analysis not included.

CSample prepared and analyzed twice to insure accuracy.










SCHEME II


H H 20C2CH3
0\




I 0

3g6 H CHC 2CfHf













EVE in methylene chloride were mixed in a nuclear magnetic resonance
6 O

L 47 48

1,4-dipoie coupling

1:1 Copolymer

the 1,2-diazetidine can be observed by nuclear magnetic resonance

analysis as described following. Equimolar quantities of PhTAD and

EVE in methylene chloride were mixed in a nuclear magnetic resonance

tube at -10, which was then placed in the spectrometer. The

temperature was regulated to -9, and the first scan of the

colorless solution, which contained mostly 1,2-diazetidine, 49

and some copolymer, produced a triplet at 61.48 (protons "a" as

assigned in 49), a multiple centered at 54.0 (presumably "b" -

poor resolution prevented quartet assignment), a multiple centered

at 64.65 (protons "c"), a triplet at 65.80 (proton "d"), and a

singlet at 67.65 (protons "e"). The solution was warmed to +20,

and continuous sweeps were made to witness changes in the nuclear

magnetic resonance pattern. Over a period of 30 minutes, the

kinetically favored 1,2-diazetidine opened to form copolymer, resulting

in broadening of the methyl, methylene, and phenyl signals while










Energy Diagram for Reaction of PhTAD/EVE and PhTAD/DVE
1,4-Dipoles

-- PhTAD/EVE

S--- PhTAD/DVE
Potential
Energy




1,2- 1.4-
diazetidine ---- Dipole --- copolyrer

Progress of Reaction


the CH2 signal at 54.65 and the CH signal at 65.80 were lost, due to

disappearance of the 1,2-diazetidine ring structure. The broadening

of signals due to copolymerization is demonstrated in Figure 1, which

illustrates how the aromatic singlet changes with time.





H H c






CH5


49

As previously mentioned, Turner et al., observed two products

in the DVE/PhTAD reaction, the 1,2-diazetidine and the copolymer. In

this instance, the kinetically favored product is more stable than

the EVE/PhTAD 1,2-diazetidine, as shown in the same energy diagram.

This is due to the decreased donating ability of the electron pair

on oxygen in divinyl ether, which inhibits the opening of the 1,2-

diazatidine.


























I







7.56
a


I
7.56
b


7.56


I

7.56


I.
7.56


Figure 1
Aromatic Singlet of 49 As It Opens To Copolymer

Readings at five-minute intervals, "a" through "f"; first reading at
-90, all others at +20. Note the growth of a new, broadened singlet
slightly upfield, which can be assigned to the copolymer.


I t


I



7.56
c











In the PhTAD/N-vinyl carbamate reaction, the 1,2-diazetidine is

no longer kinetically favored. Once it is formed, it remains thermally

stable, and the amount generated relative to copolymer is dependent

upon the activation energies of each step. Guilbault and Butler's55

results show the ratio of copolymer to 1,2-diazetidine to be 1.9/1,

indicating the activation energy for 1,2-diazetidine formation is

greater than that for copolymer formation.

In the reactions of vinyl esters (reactions 9-12, Table III),

the l,0-dipcle, 50, is more energetic (less stable), relative to the

1,4-dipoles previously discussed, due to the decreased stability of

the positive center. This is a result of lowered resonance sharing

of the ester oxygen's electron pair. The more energetic 1,4-dipole,














50

manifested in its dramatically slower rate of formation, can participate

in other reactions as well, as is exemplified in Scheme III. The

1,4-dipole apparently has four options, each controlled by each

pathway's activation energy. The 1,4-dipole may either couple to

yield alternating copolymer (path "a") or close to 1,2-diazetidine

(path "b") as before. Two new reactions appear to be occurring also,

intramolecular rearrangement (path "c", discussed in Section "B" of

this chapter), and nucleophilic attack on another molecule of PhTAD










0- O

6C5


SCHEME III
Ch2=
+ C

0
F--
'\


Sd
-----)


0 a


C6H
RS


/b


H R


g65


copolymer











(path "d"), giving 51, leading to copolyner (path "e"). The 1,2-

diazetidines are thernally stable at 60; thus, the energy picture

for this route parallels that of the formation of the PhTAD/N-vinyl

carbamate 1,2-diazetidine.

PhTAD is kno,. to slowly decompose at 60 (10% conversion after

24 hours)61 and probably accounts for a part of the greater than

1:1 PhTAD/vinyl ester comonomer molar ratio. However, the rate of

decomposition is not large enough to completely explain the high

molar ratios; the balance of the increase in the ratios for these

copolymers could be accounted for by nucleophilic attack by the

1,4-dipole on another molecule of PhTAD (path "d"). Experimental

evidence is consistent with this hypothesis. Table IV lists the

comonomer molar ratios, calculated using equation 2, for the PhTAD/

vinyl benzoate (VB) copolvyerizations as both the comonomer feed

ratio and the temperature are changed. Note that the ratio increases

as the feed ratio (FhTAD/VB) increases. The ratio also increases

as the reaction temperature increases, which is consistent with the

activation energy of path "d" being greater than path "c".


Table IV

Comonomer Molar Ratios for Vinyl Benzoate Copolymerizations

Feed Ratio (PhTAD/VB) Temperature n /n2

1:1 RT 1.27/1

10:1 RT 2.37/1

1:1 600 1.32/1

10:1 600 2.82/1







29




While the structures of these ccpolymers are not identical to

that of the other 1,4-dipole copolymers, they appear to be at least

similar in structure, having broadened nuclear magnetic resonance
-i
signals and almost identical infrared spectra. The 1610 cm.1

is present for all three copolymers, suggesting the presence of the

-C=N- linkage in the repeat unit.

Methods of termination of the propagating 1,4-dipoles are assumed

to be the same as those proposed for the one-to-one alternating

copolymers.











B. The 1,4-Dipole Intramolecular Rearrangement

Reactions of PhTAD and vinyl esters

As mentioned in Chapter 1, Turner and Butler56 found the reaction

of PhTAD and vinyl acetate to yield an adduct, 34, by means of an

intramolecular rearrangement of the 1,4-dipole, instead of the expected

copolymer. While cycloaddition reactions of 1,4-dipoles are well

documented, intramolecular rearrangements of these dipoles have

rarely been observed.62 In an attempt to clearly define the mechanism

of the PhTAD/vinyl acetate reaction, a variety of vinyl esters were

reacted with PhTAD varying the size and the electronic stabilizing

ability of the substituents. The results of these reactions are

shown in Scheme IV.

Equimolar quantities of PhTAD and isopropenyl acetate, 52,

reacted in methylene chloride at 600 yielding l-acetylmethyl-2-phenyl-

1,2,4-triazoline-3,5-dione, 53, exclusively. The infrared spectrum

and the elemental analysis were consistent with the assigned structure.

In Figure 2, the nuclear magnetic resonance spectra of 34 and 53 are

compared. Note that when isopropenyl acetate is used as a reactant

instead of vinyl acetate, the methyl signal of 53 replaces the aldehyde

signal of 34 while the other signals remain in the same positions.

Nuclear magnetic resonance data for these and the other products of

the PhTAD/vinyl ester reactions may be found in Table V.

Vinyl chloroacetate, 54, reacted with PhTAD producing 1-formylmethyl-

2-chlorcacetyl-4-phenyl-l,2,4-triazoline-3,5-dicne, 55, exclusively.

Structural assignment was based upon the product's nuclear magnetic

resonance spectrum, elemental analysis, and its infrared spectrum,












SCHEME IV


0= -0 + C0 R2
R 2

6 0





R1 R2

52 CH CH

54 i1 CH2Cl

56 H C6H
655
59 H CIi(CH3)2

62 H C(CH3)3
33


0


I-






RI R2
6 5


R 3 3

53 CH3 CH3

55 II CIH2Cl

57 H C H
-- 6 b
60 H CH(CH3)2

63 H C(C 3)2


/'o


0R2



0C615


1 R2





58 H C6H5 + polymer

61 H CH(CH3)2 + polymer

64 H C(CH3)2 + polymer































I 1 I I I r -
9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 (PPM)

"a"

spectrum of 53















----I I ---- I ---I -
10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 (PPM)

"b"

spectrum of 3463


Figure 2

Comparison of Nuclear Magnetic Resonance Spectra of 51 and 34










Table V a Nuclear Magnetic Resonance Data for the Vinyl Ester/PhTAD Reactions




R ) (-C A) H R
R_ R 2 R"4 ^ -x
I 2


C6 5 C65

Compd. RI R2 A Compd. R Ha Hb Hx B AX BX

53 .2.10(s,3) 2.52(s,3) 4.78(s,2) 58 b 4.20C(m) 6.19(m)

55 9.60(s,1) 4.97(s,2) 4.72(s,2)
61 2.54(d,6) 4.58(q,l) 4.29(q,l) 6.56(q,l) 10 6 5
57 9.66(s) b 4.78(s) 2.23(d,6)

60 9.57(s,) 4.15(m,1) 4.79(s,2) 64 1.20(s,9) 4.60(q,l) 4.27(q,l) 6.49(q,l) 10 6 5
1.25(d,6) -

63 9.53(s,l) 1.37(s,9) 4.63(s,2)

In chloroform-dl with 1% TMS as internal standard. Values reported in 6 units. N-phenyl protons appeared'
in 7.41-7.506 region for all compounds. Abbreviations used are: s=singlet, d=doublet, q=quartet, m=multi-
plet.
bComplex multiple absorption in the 7.2-7.86 region was observed for the two phenyl groups.

Complex absorption pattern for both protons.











-1
which exhibited weak aldehyde bands at 2880 and 2745 cm.- and strong

carbonyl bands at 181C and 1730 (broad) cm.-1

Vinyl benzoate, 56, yielded three products in reaction with PhTAD.

l-Formylmethyl-2-benxoyloxy-4-phenyl-l,2,4-triazoline-3,5-dione, 57,

resulted in low yield, its structure ascertained by nuclear magnetic

resonance analysis. 3-Phenyl-6-benzoyloxy-l,3,5-triazabicyclo[3.2.0]

hepta-2,4-dicne, 58, was formed in lo- yield, and structural assignment

was also based upon nuclear magnetic resonance analysis. The major

product of the reaction was a low molecular weight copolymer, discussed

in section "A" of this chapter.

Vinyl isobutyrate, 59, also afforded three products in reaction

with PhTAD, but the major product was l-fcrmylmethyl-2-(2-methyl-

propionyl)-4-phenyl-1,2,4-triazoline-3,5-dione, 60, instead of the

1,4-dipole copolymer. The infrared spectrum of G0 exhibited weak
-l
aldehyde bands at 2870 and 2750 cm.-1 and carbonyl bands at 1800,
-I
1735 (broad). and 1720 cm.-. Nuclear magnetic resonance and elemental

analysis also supported assignment of structure. The third product

of the reaction, 3-phenyl-6-(2-methylpropionyloxy)-l,3,5-triazabicyclo-

[3.2.0] hepta-2,4-dione, 61, produced three strong carbonyl bands
-1
in the infrared spectrum at 1780, 1755, and 1720 cm. corresponding

to the three carbonyls present in the adduct. Elemental analysis

and nuclear magnetic resonance analysis (in comparison with the

nuclear magnetic resonance spectra of other 1,2-diazetidines recorded
42
by von Gustorf, et al. ) also supported the structure.

The vinyl pivalate, 62, /PhTAD reaction yielded 1-formylmethyl-

2-(2,2-dimethylpropionyl)-4-phenyl-1,2,4-triazoline-3,5-dione, 63,











and 3-phenyl-6-(2,2'-dimethylpropionyl)-l,3,5-triazabicyclo[3.2.0]

hepta-2,4-dicne, 64, along with a low yield of copolymer. The

products were identified by infrared, nuclear magnetic resonance.

and elemental analysis as before.

With the exception of 53, all of the trisubstituted 1,2,4-

triazoline-3,5-diones were substituted acetaldehydes. Normally,
64
the aldehyde proton is observed to couple with the adjacent methylene.

These aldehydes, however, exhibited no coupling at all. A sample of

34 was subjected to nuclear magnetic resonance analysis from -200

to 800, and no coupling was observed; use of a 100 MHz spectrometer

also produced no coupling. The methine proton of the analogous

acetal 1-(1,l-diethoxy-2-ethyl)-2-hydro-4-phenyl-l,2,4-triazoline-

3,5-dione did exhibit coupling (64.80, triplet, j=2 Hz.), but the

coupling constant was smaller than those observed for similar acetals.6

Apparently, the phenomenon that prevents coupling of the aldehyde

proton in 34 also lowers the coupling constant of the corresponding

acetal.

In general, the yields for the PhTAD/vinyl ester reactions were

greater than 85%. Mass spectra were made for all products having

nuclear magnetic resonance data, and the molecular ion was detected

in each case.


Mechanistic aspects of the reaction

A plausible mechanism for these reactions involves a 1,4-dipole,

65, as the reactive intermediate, formed via initial reaction of the

electron rich double bond of the vinyl ester with the electron poor







36 .


65


nitrogen, nitrogen double bond. The 1,4-dipole, once formed, undergoes

intramolecular nucleophilic attack by nitrogen on the carbonyl carbon

displacing the ester oxygen (path "a", Scheme V).

Intramolecular nucleophilic attack by nitrogen is sterically

hindered by large R, groups, decreasing the relative yield of the

rearrangement product (Table VI); thus, while the 1,4-dipoles formed


Relative

Rearrangement
Product (%)


Ester


Table VI

Yields of Products

1,2-dia-
zetidine(%)


52, 54 100 0 0

59 77 8 15

62 42 42 16

56 6 7 87




in the reaction of 52 and 54 with PhTAD rearrange exclusively, the

dipoles of 56, 59, and 62 yield two other products as well, 1,3,5-


Copolymer (%)



































0




crC


Ill





I,
0 0





















0
m



--


(Ni











triazabicyclo[3.2.0] hepta-2,4-diones by path "b", Scheme V, and

copolymers by the mechanism discussed in section "A" of this chapter.

A third mechanistic possibility reaction through an acylium

ion can be eliminated on the basis of two reactions listed in

Table VI. A highly unstable chlcroacylium ion would be required

as the reactive intermediate in the reaction of 54 with PhTAD.

Also, 56 reacts with PhTAD to give ccpolymer as the major product,

contrary to what would be expected (i.e., a high yield of 57) if

a benzacylium ion were the reactive intermediate.

In an attempt to obtain kinetic and thermodynamic data supporting

the existence of the proposed 1,4-dipole, the reactions were studied

spectroscopically monitoring PhTAD's visible absorbance at 545

nanometers. Assuming irreversibility, the reactions were found

to be second order overall and first ordar in each reactant. Table

VII lists the second order rate constants at 600 along with the energies

of activation, calculated by the Arrhenius method,66 and the entropies

of activation, calculated using equation 3.67


ASa= entropy pf activation
k = 2nd order rate constant
K = 1.38 X 10-16 erg deg.-1
Equaton (in k KT Ea h = 6.62 X 10-27 erg sec.
a= (n k n RT R = 1.99 i/mol. sec.
AEa = energy of activation


A large, negative entropy of activation is often observed for

reactions involving a charged transition state. For example, the

reaction of aniline and bromoacetophenone is thought to proceed via

a charged transition state, shown below, and has an entropy of

activation of -50 cal/deg. mol.6 The PhTAD/vinyl ester reactions












Table VIIab

Kinetic and Thermodynamic Data for the Vinyl Ester/PhTAD Reactions


Ester RI R2 k AEact Sact
1-
Isopropenyl Acetate CH CH 2.7 x 10-1 7.4 (0.977) -41
3 3

Vinyl Acetate H CH3 4.2 x 10-2 12 -32

Vinyl Isobutyrate H CH(CH3)25.9 x 10-2 12 (0.977) -32

Vinyl Pivalate H C(CH3)3 4.0 x 10- 12 -31

Vinyl Chloroacetate H CH2,C 8.1 x 104 14 (0.9S7) -30

Vinyl Benzoate H C6 H 4.3 x 10-2 11 (0.988) -34


aThe coefficient of


correlation was calculated for the rate constants


and the energies of activation and is reported in parentheses. If

no value is shown in the table, the coefficient of correlation is

0.999 or better.

bThe units for the rate constant "k" are i/mol-sec. The units for

the activation energy are Kcal/mol, and for the entropy tern,

cal/mol-degree.







40'


+H 0







closely parallel this situation, and the relatively large negative

values for the entropies of activation are consistent with a charged

transition state leading to a 1,4-dipole, since an increase in the

order of the system results from adduct formation and solvent

attraction to the charged species.

The size of R2 has no effect on the energy of activation as

shown by the R2:alkyl series. This is indicative of an intermediate

being formed, followed by nucleophilic attack effecting rearrangement.

Since the relative yield of the intramolecular rearrangement product

decreases as the size of R2 increases (Table VI), the product ratios

must be determined by the activation energies in the second step

of the mechanism, the intramolecular rearrangement. The possibility

of product formation occurring from other than a common intermediate

was considered, i.e., formation of the intramolecular rearrangement

product and copolymer by opening of the 1,2-diazetidine ring. This

pathway was eliminated by determining the 1,2-diazetidine to be

thermally stable under the reaction conditions employed.











The ease of formation of the 1,4-dipole is directly affected

by the inductive effects of RI and R2. Changing RI from a methyl

group to a hydrogen increases the activation energy 4 1/2 kcal/mol.,

demonstrating the importance of cation stabilization. The 1,4-dipole

is destabilized further by placing a chloromethyl group at R2, a

phenomenon analogous in the opposite sense to the increase of the

acidity of chloroacetic over acetic acid. The activation energy

for the vinyl benzoate reaction is slightly lower than for the R2

alkyl series, possibly due to conjugation of the ester carbonyl with

the aromatic ring allowing increased lone pair sharing by the ester

oxygen. The failure of vinyl trifluoroacetate to react with PhTAD

can be attributed to the destabilizing electronic effect of the

three fluorTnes. Apparently, the activation energy required for

formation of the I,LL-dipole is too large to be overcome at C0;

thus, no reaction is observed at this temperature.










C. Bis-Triazoline-Dione Copolymerizations

Synthesis of bis-triazoline-diones

Two bis-triazoline-diones were used in this study, one prepared

using procedures developed by Saville52 and Turner, and the other

by modification of these procedures.

Bis-(p-3,5-dioxo-l,2 4-triazolin-4-ylphenyl)methane, 69, was
52
prepared by the sequence of steps illustrated in Scheme VI. One

mole of bis-(4-isocyanatophenyl)methane, 66, reacted with two moles

SCHEME VI


OCN- -CH2 + 2 FH2 O12CH3 --C
+ H


CH3CH32CH20 D 2 H
fH H H2


1) KOH, aqueous
2) H+


-CH2 fuming
2 HN0
2 3


0


H I
I 0/C 2


of ethyl carbazate yielding the bis-semicarbizide, 67. Cyclization

of this bis-semicarbizide was achieved by slowly adding the solid to

a 2i solution of potassium hydroxide, followed by neutralization and










filtration of the bis-urazole, 68. Oxidation to the desired bis-

triazoline-dione, 69, was done using fuming nitric acid.

1,6-Hexane-bis-1,2,4-triazoline-3,5-dione, 73, was prepared in

a similar fashion and is shown in Scheme VII. The corresponding


SCHEME VII

CH CH3 OfYiN-(CH2) 6-K lo:CCHCH2
HHI H H


1) KOH
) H+


HO 111N-(CH )-U6 KL OH
HH H H H j



-2 CO2





H2NlU(CH2 6



71


C:aOCH2CH3/CH2CH30 H
2 3. 2 3


2
0 C


Hfl -2 -y;


N20


bis-semicarbizide, 70, was prepared as before; however, attempted

cyclizatir. in either aqueous or alcoholic 2M potassium hydroxide

led to hydrolysis of the ester function followed by decarboxylation -

detected by infrared analysis of the CO2 evolved giving the

proposed structure, 71. The cyclization was achieved by refluxing












70 in a sodium ethoxide/ethanol solution overnight, followed by

filtration of a light tan solid. Since the light tan solid was

extremely water soluble and had a high melting point, it is likely

that it existed as the sodium salt of the diurazole. Oxidation

of the tan solid using dinitrogen tetroxide yielded the desired

bis-triazoline-dione, 73. If the tan solid was dissolved in water

and the resultant solution was neutralized with 50% HC1, a low yield

of the diurazole, 72, characterized by nuclear magnetic resonance,

infrared, and elemental analysis, precipitated from solution.


Copolymerizations of bis-triazoline-diones and divinyl esters of
dicarboxylic acids


In an attempt to employ the intramolecular rearrangement discussed

in section "B" of this chapter as a mode of propagation for copolymer-

ization, 69 and 73 were reacted with diisopropenyl adipate, 74,

and divinyl adipate, 75, prepared by the reaction of isopropenyl70

and vinyl acetate7 with adipic acid. Diisopropenyl adipate was

used as a comonomer to lower the energy of activation necessary to

cause copolymerization; thus, it was hoped that lower temperatures

could be used for copolynerization, decreasing the possibility of

copolymer degradation. Although this effect was not observed all

the copolymers characterized were of approximately the same molecular

weight the time necessary for complete reaction was decreased by

a factor of two when 74 was used as a comonomer. The results of

all of the copolymerizations are summarized in Scheme VIII.









SCHEME VIII


insoluble solid


+ CH2=C-OC (CH2 4 CO=C{I2 ---


R1

(CH2)6

2CH2 6

-( CH 2
(CH2 )6


2 4

0
Xo


R1

(CH2)6
2 6


-@- H 2>

(CH2 )6


R2

CH3
H


I-
11











The copolymerization of 73 and 74 in retrahydrofuran was studied

at room temperature and 600, and in both cases the characteristic

red color of 73 discharged to light yellow while a light yellow

opaque gel formed. The gel was filtered, and the filtrate was slowly

added to a tenfold excess of hexane causing precipitation of an

off-white solid. In both cases the yield of precipitated solid was

less than 10% of the theoretical. The nuclear magnetic resonance

spectrum of the precipitate gave resonance signals at 61.5 (broad

mulitplet, protons "a" in Figure III), 61.7 (broad multiple, protons

"b"), 62.1 (singlet, protons "c"), 63.0 (broad multiple, protons "d"),

63.6 (broad multiple, protons "e"), and 64.8 (singlet, protons "f").

Comparison of this spectrum with the spectra of model compounds 80 -

prepared in an 80% yield by reaction of 73 with two moles of isopropenyl

acetate and 81 synthesized in a 90% yield by the reaction of 74







2 6

/ 0


0 (CH2 ) 0



C~3










with two moles of 4-methyl-1,2,4-triazoline-3,5-dione allowed

the assignment of 76 as the copolymer's structural repeat unit.

Infrared and elemental analysis confirmed the assignment of structure.

The assignment of nuclear magnetic resonance signals to the proton

type is shown in Figure 3. Vapor pressure osmometry in acetone

gave a number average molecular weight of 1780.










e b e

O'CH3 CH3g
c c

Ln

Figure 3

Assignment of Proton Type to Nuclear Magnetic Resonance
Signals for 76

a, 61.5; b, 61.7; c, 62.1; d, 63.0; -, 63.6; f, 44.8


In both the room temperature and the 600 copolymerizations,

the light yellow gel was generated in greater than 80% of the

theoretical yield and was insoluble in most organic solvents.

Swelling was noted in dimethylformamide and dimethylsulfoxide, however.

Although the infrared spectrum was almost identical to the spectrum

of the soluble copolymer, it was difficult to make a structural

assignment based upon this evidence along. A sample of the solid












was heated to 600 in dimethylsulfoxide-d for five hours, and about

10% of the solid was solubilized. Nuclear magnetic resonance

analysis was inconclusive, however, since it was possible that

copolymer degradation could have occurred under these conditions.

Resonance signals at 61.8 and 63.6 were assigned to the solvent,

tetrahydrofuran, which was apparently trapped with the copolymer.

The elemental analysis was consistent with this conclusion since

the carbon, hydrogen, and oxygen percentages were higher than those

calculated for a 1:1 comonomer ratio in the copolymer.

The soluble, low molecular weight copolymer, 79, resulting from

the reaction of 73 and 75 in tetrahydrofuran, was also prepared at

room temperature and 600. As before, no noticeable difference was

detected by increasing the reaction temperature other than decreasing

the time necessary for complete reaction. The major product of

the copolymerization (83%) was an insoluble gel solvated by tetra-

hydrofuran.

The copolymerization of 69 and 75 was attempted in tetrahydro-

furan at 600 producing a 75% yield of an insoluble gel and a 12%

yield of a soluble copolymer, 77. Structural assignment of 77 was

based upon nuclear magnetic resonance, elemental, and infrared

analysis. The insoluble gel swelled in dimethylformamide and dimethyl-

sulfoxide, and a nuclear magnetic resonance spectrum of a sample

solubilized in dimethylsulfoxide-d6 by heating gave very broad signals

from which no definitive proton assignments could be made. The

copolymrer was solvated by dimethylformamide as evidenced by signals

at 62.8 doublett) and 67.9 (broad singlet). The elemental analysis












also gave this indication. As before, the infrared spectrum was

almost identical to that of the soluble copolymer.

The copolymerization of 69 and 74 in tetrahydrofuran, yielding

a soluble copolymer and an insoluble solid, proceeded in a manner

analogous to the formation of 76 and 77. As before, the low

molecular weight, soluble copolymer, 78, was fully characterized,

while conclusive assignment of a copolymer repeat unit structure

for the insoluble solid was not feasible as only an infrared spectrum

could be made.

With the intention of preparing a thermally stable copolymer,

shown below, by reaction of diisopropenyl terephthalate and p-phenyl-

bis-1,2,4-triazoline-3,5-dione, the synthesis of diisopropenyl


F


0 0



I 3 C3 0





terephthalate was attempted. No success was achieved in reacting

terephthalic acid and isopropenyl acetate using a procedure similar

to that previously tried. Apparently, the insolubility of the

diacid prevented reaction from occurring. Dimethyl terephthalate

was used in an attempted ester exchange with isopropenyl acetate,

and although the reaction medium was homogeneous and a color change

was noted, the desired diester could not be isolated. No further











synthesis work was attempted, and the thermally stable copolymer

was not synthesized.

Although the insoluble copolymers were never fully characterized,

it is reasonable to assume that the 1,4-dipole intramolecular rear-

rangement was at least one of the propagating reactions responsible

for their formation. Therefore, two possibilities should be considered

as explanations of the insolubility of these copolymers. Due to

the high polarity of the copolymer backbone, interchain attraction

would account for the intractability of the solids. If this is the

case, then solution would be caused by solvation of the copolymer

backbone in hot dimethylsulfoxide-d6, replacing interchain attraction.

The other possibility would involve chemical crosslinking.

That is, a reaction undetected in the intramolecular rearrangement

model compound studies, possibly vinyl polymerization of vinyl ester

end groups, would chemically bond the copolymer chains forming an

insoluble gel. In this case, heating the copolymer in dimethyl-

sulfoxide-d6 would result in a chemical breakdown of the crosslink,

degrading the copolymer.


Diels-Alder ene copolymerizations

Cookson, Gilani and Stevens3 have investigated the Diels-Alder

reactions of PhTAD and found, in reaction with styrene, a double

Diels-Alder adduct, 82, was obtained. Reinvestigation of the

reaction by this author revealed that a Diels-Alder-ene adduct, 83,

was also formed, as shown in Scheme IX, in approximately a 2:1 ratio

(ratio computed by nuclear magnetic resonance analysis) of 83 to 82.







51

SCHEME IX



R +





PhTAD C 6H
84 CH
3






LR


YaI y H

0 0





82 CS 5 83 C 6H
85 CH 86 CH3

Separation of the mixture by fractional crystallization yielded

pure samples of both adducts, 82 being identified by comparison

with the results of Cookson et al., and 83 characterized by infrared,

mass spectral, elemental and nuclear magnetic resonance analysis.

Deuterium exchange with the proton on nitrogen was also observed

in the nuclear magnetic resonance spectrum. 4-Methyl-1,2,4-triazoline-

3,5-dione, 84, also reacted with styrene yielding both products in

the same approximate ratio, 2:1 of 86 to 85. Purification of 8672

was achieved via fractional crystallization and structural assignment

was based on analyses described above including ultraviolet analysis













to ascertain the presence of the reformed aromatic ring. Attempts

to separate 85 from 86 by fractional crystallization and column

chromatography were unsuccessful; however, its presence was assured

by a detailed examination of a nuclear magnetic resonance spectrum

of the mixture, in comparison with the spectrum of a pure sample

of 86.

Nuclear magnetic resonance analysis of the Diels-Alder ene

products disclosed a doublet around 68.2 which has been assigned

as one aromatic proton. For example, the nuclear magnetic resonance

spectrum of 86 (Figure 4) exhibited a doublet at 68.23; specific

proton assignment was impossible, however, based on these data

alone since it could have been either "fl" or "f2" in Figure 4.

Unequivocal proton assignment was achieved, by reacting 84 with

3,4,5-trideuteriostyrene* by the procedure described for the reaction

with styrene, resulting in the Diels-Alder ene product, 87, as one

of the products. The nuclear magnetic resonance spectrum of 87

(Figure 5) showed loss of the doublet and the appearance of a

singlet in the other aromatic region; thus, the doublet's proton

assignment in 86 must have been,"f2", "fl" being found in the

aromatic region.

These results suggested the Diels-Alder ene reaction as a

possible propagation mechanism in copolymerizations of styrene and

bis-triazoline-diones 69 and 73. Both comonomers were reacted with



Sample provided by Dr. H.J. Harwood, The University of Akron, Akron,
Ohio.






a h








The N-H proton (g) is further
downfield at 10.106. a

I





2 t1 ^ 70 Ie


DMSO-d6
6


8.0 7.0 6.0 5.0 4.0 3.0 2.0 (PPM)

Figure 4

NMR Spectrum of 86









a b


The N-H proton (f) is further
downfield at 10.106. a
CH3 i










e b -




d
II



I II DMSO-d6


SI / I
^.r ^^ -s ^_^^J-^.^/^JlV ^- w.^. Ij'- i~,/-- -^
8.0 7.0 6.0 5.0 4.0 3.0 2.0 (PPM)

Figure 5

NMR Spectrum of 87










styrene, and the results are given in Scheme X.


SCHEME IX.






o 0
\

69 -@cH2Q-

73 (CH2)
6

7-H

0 +





88A CH21

J n
89 -(CH 26-


Reaction of concentrated solutions of 69 in dimethyl formamide

with equimolar quantities of styrene rapidly yielded high molecular

weight copolymer, 88, En] = 0.33 dl. g. Structural assignment was

based on infrared, elemental, and nuclear magnetic resonance analysis.

Deuterium exchange with the proton on nitrogen was also observed

in the nuclear magnetic resonance spectrum; nuclear magnetic resonance

analysis did not disclose the repeat unit ratio (B:A), however, due

to poor resolution of the extremely viscous nuclear magnetic resonance

solution. The copolymer was soluble in dimethylformamide, dimethyl-

sulfoxide, hexafluoroisopropanol, hexamethylphosnhorictriamide, and












N-methylpyrrolidone, and insoluble in ethyl ether, tetrahydrofuran,

ethyl acetate, methanol, methylene chloride, acetonitrile, benzene,

acetone, nitromethane, and water.

Turner73 also investigated the copolynerization of 69 and

styrene, and although a copolymer was isolated, the elemental analysis

was not consistent with a 1:1 reaction of comonomer in the copolymer.

The nuclear magnetic resonance spectrum of the copolymer also gave

evidence of the Diels-Alder ene repeat unit ("B" in Scheme IX)

being present in the copolymer, however.

Reaction of a dilute solution of 73 in methylene chloride

with an equimolar quantity of styrene rapidly yielded a low molecular

weight copolymer, 89, En] = 0.08 dl./g. Vapor pressure osmometry

studies in methylene chloride gave a number average molecular weight

of 2300. Structural assignment was based on analyses described for

88 including ultraviolet spectroscopy, which confirmed the presence

of the aromatic ring in repeat unit "B". As before, deuterium

exchange with the proton on nitrogen was noted in the nuclear magnetic

resonance spectrum, and an approximate 2:1 ratio of repeat units "B"

to "A", respectively, was calculated from the spectrum. The copolymer

was soluble in methylene chloride, dimethylformamide, dimethylsulfoxide,

chloroform, and 1,1,2,2-tetrachloroethane, and insoluble in acetone,

benzene, acetonitrile, and water.

The nuclear magnetic resonance signals for the model compounds,

82, 83, 85 and 86,are reported in Table VIII, and may be compared

with the signals of the copolymers, 88 and 89, listed in Table IX.











Table VIII
1
Nuclear Magnetic Resonance Data for the Diels-Alder Ene Model Compounds




0



a N a


Compd. a b
5.63(m,l)
82 4.35(m,2) 6.15(m,l)
6.47(m,1)


85 4.38(m)


5.58(m)
6.00(m)
6.45(m)


c
6.77(t,2)
J=3.5 Hz


6.73(t)
J=3.5 Hz


d- e

7.21( 3 7.2(s)
7.48(s)


2.89(s)
2.95(s)


Compd. a

83 4.03(m,2)


5.43(t,l) 7.17(m)4


d
7.20(s)4
7.25(s)4


e

8.19(d,1)
J=7 Hz


86 4 03(m,2) 5.50(t,l) 7.42(m ) 2.87(s,3) 8.23(d,l)
6" J3 Hz 2.98(s,3) T=7 Hz


f5,5
6'


10.42


10.10


1 In DMSO-d6, 1% TMS. Values reported in 6 units. Abbreviations used
are a, singlet; d, doublet; t, triplet; m, multiple.
2 Signal partially hidden in aromatic absorption.
3Eleven nrotons total.
4 Thirteen protons total.
5Very broad signal.
6 Protons on nitrogen were found to exchange wiith deuterium when 1
drop of D20 was added to the nuclear magnetic resonance tube.


~












Table IX Nuclear Magnetic Resonance Data for the Diels-Alder Ene Copolymers


e


0





A n


88 R -( -J H2H/'&-
g2 c g2

89 R -CH2--(CH2)4-CH2-
b a b


B R
\ n


Polymer a b c d e f g h i

5.59
88 4.19 6.05 6.68 7.16 7.35 (gl & g2) 8.21 10.40
6.43

5.54
89 1.33 3.40 4.25 5.98 6.67 7.20 7.38 (gl only) 8.25 (d) 10.00
6.39



t Polymers gave poorly resolved nuclear magnetic resonance signals. Two signals were not identified,
one at 3.26 in [13] and the other at 4.88 in [14]. Note that letter designations for protons in the
polymers are not identical to the letter designations for protons in the model compounds.

a Signal for protons a to nitrogen in repeat unit D and one of the protons a to nitrogen in repeat unit
A. The two remaining signals are due to the other protons a to nitrogen in A.












D. Potential Applications

A characteristic common to the three classes of copolymers

discussed in this dissertation is the high polarity of the copolymer

backbone. While the resultant interchain attraction can cause

solubility problems, it can also serve a useful purpose in each

case. Further developmental work will be necessary, however, before

the copolymers can be exploited.

The major drawback of the 1,4-dipole copolymers is their low

molecular weight. If methods can be devised to raise the molecular

weight, then it is possible that they could be structurally useful.

The 1,4-intramolecular rearrangement also could be structurally useful

as well as thermally stable if the problem of insolubility can be

overcome.

The rapid, room temperature gelling of the Diels-Alder ene

copolymer solutions may have application, such as a convenient

method of suspending homoneneous solutions. The major drawback

here lies in the exothermicity of the reaction. A large amount

of heat is released, and scale up of this reaction could lead to

difficult problems.



















CHAPTER III

Experimental

A. General Information

Infrared spectra were taken on a Beckman IR-8 spectrophotometer

and proton nuclear magnetic spectra on a Varian A-60A spectrometer

except as noted. Mass spectral data were obtained using a Hitachi

Perkin-Elmer RMU mass spectrometer. All ultraviolet and visible

spectra were measured with a Beckman DK-2A spectrometer equipped with

a Beckman 92529 Temperature Regulated Cell Holder for variable temper-

ature work. Number average molecular weights were measured with a

Mechrolab Model 302 Vapor Pressure Osmometer, and intrinsic viscosities

were obtained by standard procedure using a Cannon-Ubbelohde semimicro

dilution viscometer.

Melting points were taken on a Thomas-Hoover melting point

apparatus and are reported in degrees centigrade uncorrected. Boiling

points are also uncorrected and reported in degrees centigrade.

Elemental analyses were completed by either Atlantic ricrolab,

Inc., Atlanta, Georgia or Peninsular ChemResearch, Inc., Gainesville,

Florida.

All reagents used in monomer synthesis, copolymerizations, and

model compound studies were obtained commercially and used as received

except as noted. All solvents were commercial grade and used as

received with the exception of the solvents used in the visible

absorption studies, which were spectral grade.

60











B. Synthesis of 4-Phenyl-l,2,4-Triancline-3,5-dione

Ethyl carbazate4

Diethyl carbonate (1.80 mol., 200.0 g.) and 99% hydrazine hydrate

(1.80 mol., 88.0 g.) were stirred at room temperature for one half

hour. Initially the two phase system reacted with mild exothermicity,

and one phase resulted. The clear liquid was distilled twice at 950

and 12 mm. yielding 130 g. (74.2%) of a liquid which on standing

solidified to a white solid, m.p. 45-470 (lit. 444-45.50).


l-Ethoxycarbonyl-4-phenylsemicarbizide7

Ethyl carbazate (0.64 mol., 62.0 g.) was dissolved in 200 ml.

benzene and was brought to 100 in a three-necked round bottomed flask

equipped with an addition funnel, a reflux condenser fitted with a

drying tube, a thermcmeter and a mechanical stirrer. Stirring was

initiated and phenyl isocyanate (0.64 mol., 59.0 g.) in 100 ml. benzene

was added dropwise through the addition funnel keeping the temperature

between 100 and 20. As the addition proceeded, a white precipitate

appeared and remained until the addition was complete. The mixture

was refluxed for one half hour, resulting in solution of the precipitate.

Upon cooling the precipitate reappeared and was filtered. The

precipitate was washed with two 75 ml. portions of cold benzene

yielding 110.2 g. (91.3%) of a white solid, m.p. 151-520 (lit.74 154).


4-Phenyl urazole74

l-Ethoxycarbonyl-4-phenylsemicarbazide (0.55 mol., 124.0 g.) was

added to 300 ml. hot, stirred 4M potassium hydroxide. Upon complete

solution, the light yellow solution was filtered and cooled. The

solution was acidified with 50% hydrochloric acid resulting in a










voluminous white precipitate. The precipitate was vacuum filtered

and washed several times with cold water. The filtrate was tested

for additional precipitate by slowly adding 50% hydrochloric acid.

Any solid that appeared was filtered, washed and combined with the

original precipitate. The precipitate was dried overnight in a

vacuum oven yielding 69 g. (78.1%) of a white solid, m.p. 204-2080

(lit.74 206-70).


4-Phenyl-1,2,4-triazoline-3,5-dione8

4-Phenyl urazole (3.43x10-2 mol., 6.0 g.) was placed in a 500 ml.

Erlenmeyer flask containing 25 g. sodium sulfate; the mixture was

cooled below 50 and a nitrogen sweep was placed above the solution

level. Magnetic stirring was employed, and dinitrogen tetroxide gas

was bubbled into the solution with stirring for one half hour.

Nitrogen was passed into the solution to remove excess dinitrogen

tetroxide gas, and then the solution was allowed to warm to room

temperature. The solvent employed in the reaction, 300 ml. of methylene

chloride, was removed by a rotory evaporator, and the solid was removed

from the flask and allowed to air dry for two hours. The bright red

solid was sublimed at 0.03 mm. and 700 yielding 5.3 g. (90.6%) of a

red, crystalline solid. The material was stored in the freezer when

not in use.






63


C. The 1,4-Dipole Copolymerizations

Reaction of PhTAD and 1,2-Dimethoxyethylene

1,2-Dimethoxyethylene (0.00286 mol., 0.252 g.) (80% trans) was

dissolved in 20 nl. methylene chloride and added to a 20 ml. solution

of PhTAD (0.00286 mol., 0.500 g.) in a 125 ml. Erlenmeyer flask.

The addition caused the solvent to boil, and the characteristic red

color of PhTAD disappeared immediately. The light yellow solution

was allowed to stir an additional 15 minutes, and was then slowly

added to 500 nl. of stirred hexane. The resulting precipitate was

filtered, reprecipitated twice and dried, yielding 0.62 g. (80%) of

a white solid. Analysis identified the amorphous solid as a copolymer

having repeat units 42 and 43 softening at 160-170. The nuclear

magnetic resonance spectrum (CDC13) gave signals at 63.3 (s, broad. 3),

63.6 (s, broad, 3), 65.3 (m, broad, 1), 66.08 (m, broad, 1), and

67.5 (s, broad, 5). Infrared absorbances were found at (KBr) 2960 (w),

2860 (w), 1780 (m), 1730 (s, b), 1610 (s), 1500 (m), 1470 (m), 1440 (m),

1330 (w), 1310 (w), 1200 (m), 1110 (w), 1060 (w), 1020 (w), 950 (w, b),

750 (w, b), and 690 (w) cm.-. Vapor pressure osmometry in acetone

gave a number average molecular weight of 1860.

Anal. Calcd. for 1:1 copolymer, C12H13N30 4 C, 54.75; H, 4.98;

N, 15.96. Found: C, 54.59; H, 5.08; N, 16.06.

The filtrate of the first precipitation was evaporated on a rotary

evaporator yielding 0.090 g. (12%) of a light yellow solid. The sclid,

which by nuclear magnetic resonance analysis was shown to contain a

small percentage of copolymer, was determined to be the corresponding

1,2-diazetidine. Resonance signals were found at (CDC13) 63.30 (s),










63.61 (s), 55.43 (d), 66.91 (d), and 67.50 (s). Attempted integration

of the signals was not successful since the sample contained copolymer.

The sample was heated in tetrahydrofuran for 12 hours, followed by

precipitation as before. Nuclear magnetic resonance analysis gave

resonance signals identical to those for the copolymer containing

repeat units 42 and 43.


Reaction of PhTAD and p-2-vinyloxyethoxytoluene

p-2-Vinyloxyethoxytoiuene (0.00286 mol., 0.510 g.) was dissolved

in 15 ml. methylene chloride and was slowly added to a 20 ml. solution

of PhTAD (0.00236 mol., 0.500 g.) in methylene chloride. In less than

two minutes the red color changed to light.pink, and a white precipitate

formed in the 125 ml. Erlenmeyer flask. The color was completely

discharged in ten minutes. The solid "as filtered, and washed twice

yielding 0.493 g. (50%) of a white crystalline solid melting at 131-

1320. Analysis indicated the solid to be a copolymer structured mostly

as 44. Vapor pressure osmometry in acetone demonstrated the number

average molecular weight to be 1430. Resonance signals in the nuclear

magnetic resonance spectrum were found at (CDC31) 62.2 (s, broad, 3),

64.0 (m, very broad, 4), 66.7 (m, broad, 3), and 67.4 (s, broad, 4).

Infrared absorbances were located at (KBr) 3060 (w), 2960 (w), 1780 (m),

1730 (s), 1710 (s), 1500 (m), 1420 (m), 1360 (w), 1300 (w), 1260 (m),

1250 (m), 1170 (w), 1130 (m), 1100 (w), 1080 (w), 1020 (w), 920 (w),

870 (w), 820 (w), 800 (w), 770 (w), 740 (w), 680 (w), and 670 (w) cm.-1

Anal. Calcd. for a 1:1 copolymer, C gH 1Ig:0 4 C, 64.58; H, 5.42;

N, 11.79. Found: C, 64.66; H, 5.37; N, 11.79.










The filtrate of the reaction volume was slowly added to 500 ml.

of stirred hexane resulting in an additional 0.347 g. of 44. Structural

assignment was based upon its melting point of 129-1320 and its nuclear

magnetic resonance spectrum, which had signals identical to those of

the first precipitate. The total yield of copolymer in the reaction

was 0.840 g. (83%).


Reaction of PhTAD and l-vinyl-2-pyrrolidone

l-Vinyl-2-pyrrolidone (0.00286 mol., 0.308 g.) was dissolved in

35 ml. methylene chloride and added to a solution of PhTAD (0.00286

mol., 0.500 g.) in 20 ml. methylene chloride. The resultant solution

began to boil in the 125 ml. Erlenmeyer flask, and the red color

discharged in less than thirty seconds. The light yellow solution

was slowly added to 500 ml. of stirred hexane as before, precipitating

0.714 g. (88%) of a white solid which softened in the range of 175-

185. Nuclear magnetic resonance and infrared spectral analysis

indicated the amorphous solid to be the copolymer, 45. The nuclear

magnetic resonance spectrum gave resonance signals at (CDC13) 62.2

(m, very broad, 6), 63.6 (m, very broad, 2), 66.1 (m, very broad),

and 67.4 (s, broad, 5). Infrared abscrbances were found at (KBr)

3080 (w), 2980 (w), 1780 (m), 1720 (s, b), 1610 (w), 1500 (m), 1420 (s),

1320 (w), 1280 (m), 1270 (m), 1230 (w), 1160 (w), 1070 (w), 1030 (w),

770 (m), 690 (w), and 630 (w) cm. The number average molecular

weight was determined to be 1100 by vapor pressure osmometry using

acetone as the solvent.

Anal. Calcd. for a 1:1 copolymer, C4 H 4N03: C, 58.75; H, 4.93;

N, 19.58. Found: C, 57.05; H, 5.14; N, 18.98.










Reaction of FhTAD and N-vinylsuccinimide

N-Vinylsuccinimide (0.00286 mol., 0.358 g.) was dissolved in

30 ml. of methylene chloride and added to a 20 ml. solution of PhTAD

in a 125 ml. Erlenmeyer flask. The color rapidly disappeared giving

rise to a light yellow solution. The solution was slowly added to

500 ml. of hexane yielding a light yellow solid. The solid was

filtered and reprecipitated twice yielding 0.725 g. (85%) of a light

yellow solid. Analysis as before identified the amorphous solid to

be the copolymer, 46. The solid softened in the 150-1600 range.

The number average molecular weight was determined to be 1400 by

vapor pressure osmonetry in acetone. Nuclear magnetic resonance

signals for 46 were found at (CDC1 ) 62.6 (m, very broad, 4), 64.5

(m, very broad, 3), and 67.5 (s, broad, 5). Infrared absorbances

appeared at (KBr) 3060 (w), 2930 (w), 1780 (m), 1720 (s), 1705 Cs),

1610 (w), 1500 (w), 1410 (s), 1320 (w), 1280 (in), 1270 (m), 1200 (w),

1160 (w), 1070 (w), 1030 (w), 770 (m), 550 (w), and 620 (w) cm.-1

Anal. Calcd. for a 1:1 copolymer, C 4H N404: C, 56.00;

H, 4.03; N, 18.66. Found: C, 55.74; H, 4.19; N, 18.66.


General procedure for copolymer separation in the reactions of PhTAD

and vinyl esters

The general reaction procedure for the PhTAD and vinyl ester

reactions is described in section "D" of this chapter. The copolymer

that precipitated in hexane was redissolved in hot hexane and repreci-

pitated twice and dried at 580/0.03 mm. before analysis. Specific

information concerning these copolyners is given below.











Copolymer of PhTAD and vinyl benzoate

A white, amorphous solid weighing 0.791 g. (87%) was obtained

softening in the 150-1650 range. Vapor pressure osmometry analysis

in acetone indicated the number average molecular weight to be 1200.

Resonance signals (CDC13) in the nuclear magnetic resonance spectra

were found at 64.5 (s, broad), 67.45 (m, very broad), and 67.8 Cs,

broad). Integration of the spectrum and elemental analysis indicated

that the copolymer did not exist in a 1:1 ratio of comonomers. Infrared

absorbances were located at (KBr) 3080 (w), 1780 (m), 1735 (s,b),

1615 (m), 1600 (m), 1500 (m), 1420 (m), 1320 (m), 1250 (m), 1110 (w),

1060 (w), 1020 (w), 810 (m), and 690 (m) cm.-1

Anal. Calcd. for a 1:1 copolymer, C H N 0 : C, 63.16; H, 4.05;

N, 13.00. Found: C, 61.10; H, '[.19; N, 14.92. The molar ratio

(PhTAD/vinyl benzoate) in the copolymer was 1.27/1.


Reaction of FhTAD and vinyl benzoate using a 10:1 monomer ratio of

PhTAD to vinyl benzoate

Vinyl benzoate (0.00143 mol., 0.162 g.) was dissolved in 20 ml.

methylene chloride, and this solution was mixed with a 30 ml. solution

of PhTAD (0.0143 mol., 2.500 g.). The red solution was divided into

two equal portions, one for a study of the reaction at roon temperature,

and the other for an examination of the reaction at 60. The solution

was studied at 600 and sealed in a glass tube as described in section

"D" of this chapter. The reactions were allowed to continue for six

hours, after which the red solutions were filtered to remove a small

amount of insoluble solid and poured into 250 ml. portions of stirred

hexane. The resulting copolymers were washed several times with cold











hexane and reprecipitated into hot hexane twice. The solids were then

dried at 580/0.03 mm. overnight and submitted for analysis. The results

are given below.

Anal. for copolymer of room temperature reaction. Calcd. for a

1:1 copolyner, C73 N0 C, 63.16; H, .05; N, 13.00. Found: C,

58.09; H, 4.05; N, 17.97. The molar ratio (PhTAD/vinyl benzoate) in

the copolymer was 2.37/1.

Anal. for copolyrer of 60 reaction. Calcd. for a 1:1 copolymer,

C 7H 3N304: C, 63.16; H, 4.05; N, 13.00. Found: C, 57.08; H, 3.82;

N, 18.55. The molar ratio CPhTAD/vinyl benzoate) in the copolymer

was 2.82/1.


Copolymer of PhTAD and vinyl isobutyrate

A white, amorphous solid weighing 0.123 g. (12%) and softening

at 140-150 resulted from the purification procedure. Vapor pressure

osmometry analysis in acetone gave a number average molecular weight

of 1250. Nuclear magnetic resonance signals were observed at 61.3

(very broad), 63.6 (very broad, almost indistinguishable), 64.3 (very

broad), and 67.4 (s, broad). Elemental analysis and the-nuclear

magnetic resonance integration showed that the copolymer did not

exist in a 1:1 ratio of comonomers. Infrared absorbances were found

at (KBr) 2980 (w), 1780 (m), 1735 (s, b), 1610 (m), 1600 Cm), 1420 (m),

1250 (m), 1140 (w), 1060 (w), 1020 (w), 960 (m), 750 (m), and 690 (m)
-1
cm.

Anal. Calcd. for a 1:1 copolymer, C4 HN304: C, 58.13; H, 5.23;

N, 14.53. Found: C, 56.78; H, 4.68; N, 17.65. The molar ratio

(PhTAD/vinyl isobutyrate) in the copolymer was 1.32/1.











Copolymer of PhTAD and vinyl pivalate

As before, a white, amorphous solid resulted from the purification

procedure weighing 0.133 g. (16%). The solid melted in a range of

165-1700, and vapor pressure osmometry in acetone gave a number average

molecular weight of 1300. Other samples prepared gave number average

molecular weights in the range of 1230 to 1500. The nuclear magnetic

resonance spectrum (CDC13) gave signals at 61.1 (s, broad, 64.2 (very

broad), and 67.5 (s, broad). As with the other PhTAD/vinyl ester

copolymers, the elemental analysis and the nuclear magnetic resonance

integration demonstrated that the copolymer did not exist in a 1:1

ratio of comonomers. Absorbances in the infrared spectrum were found

at (KBr) 3080 (w), 1780 (m), 1730 (s, b), 1610 (m), 1600 (m), 1500 (m),

1450 (m), 1420 (m), 1310 (m), 1250 (m), 1180 (w), 1060 (m), 1020 (w),

760 (m), 710 (m), and 690 (m) cm. .

Anal. Calcd. for a 1:1 copolymer, C15HN3 0 4: C, 57.40; H, 5.65;

N, 13.85. Found: C, 57.59; H, 5.25; N, 16.71. The molar ratio

(PhTAD/vinyl pivalate) in the copolymer was 1.72/1.

Another sample of the PhTAD/vinyl pivalate copolymer, prepared

by the same procedure, was submitted for elemental analysis, and the

results, shown below, compared favorably with those of the first

analysis.

Anal. Calcd. for a 1:1 copolymer, C iH17N304: C, 57.40; H, 5.65;

N, 13.85. Found: C, 57.48; H, 4.91; N, 16.56. The molar ratio

(PhTAD/vinyl pivalate) in the copolymer was 1.69/1.











Nuclear magnetic resonance analysis of the PhTAD/ethyl vinyl ether

reaction at low temperatures
-5
A 100 ml. solution of ethyl vinyl ether (5.71 x 10 nol.,
-3
0.0094 g.) was prepared by diluting 1 ml. of a 5.71 x 10- molar

solution to 100 ml. A 100 ml. solution of PhTAD (5.71 x 10-5 mol.,

0.0099 g.) was prepared in an identical manner. The two solutions

were cooled to -100 in a dry ice/isopropanol bath and were then mixed

together, discharging the red color of PhTAD instantaneously. A

nuclear magnetic resonance tube was also cooled to -100, and a sample

of the above solution was introduced into the tube. The tube was

placed in the sample chamber of the spectrometer, which had been

regulated to -9, and a nuclear magnetic resonance spectrum was made

immediately. Some copolymer was present, as noted by its character-

istically broad signals, but the major signals of the spectrum were

those of the 1,2-diazetidine located at 61.48 (t), 64.1 (m), 64.65 (m),

65.80 (t), and 67.65 (s). The solution was warmed to +20, and con-

tinuous sweeps were made over a 30-minute period. During that time,

the signals at 64.65 and 65.80 disappeared while a very broad signal

at 64.0 appeared coalescing with the original signal at 64.1. The

other signals at 61.48 and at 67.65 also broadened considerably.











D. The 1,4-Dipole Intramolecular Rearrangement

General procedure
--3
To a solution of 0.500 g. (2.86 x 103 mol.) of PhTAD in 25 ml.

of methylene chloride (dried over 4-A molecular sieves) was added

a 25 ml. solution of 2.86 x 10-3 mol. of the vinyl ester. The intense

red solution was transferred to a thick-walled glass tube, which was

sealed under vacuum following two freeze-thaw cycles in liquid nitrogen.

The tube was placed in a 600 constant-temperature bath and removed

after color discharge to light yellow was noted. The tube was then

opened and the contents were poured through a coarse sintered glass

funnel into 250 ml. of stirred hexane to precipitate any copolymer

formed. Copolymer, if present, was filtered and the filtrate was

evaporated on a rotary evaporator, leaving a residue of nonpolymeric

products. The nonpolymeric products were separated and purified as

described below, and dried at 580 (0.03 mm.) overnight before analysis.

All nonpolyneric products were odorless, white, crystalline solids;

the copolymers were odorless, white amorphous solids. Nuclear magnetic

resonance data may be found in Table V. Analysis of the copolymers

is described in section "C" of this chapter.


l-Acetvlmethyl-2-acetyl-4-phenyl-l,2,4-triazoline-3,5-dione

l-Acetylmethyl-2-acetyl-phenyl-1,2,4-triazcline-3,5-dione, 53, was

recrvstallized twice from a methylene chloride-hexane solvent pair

yielding 0.56 g. (75%) of product, m.p. 130-131. Infrared absorbances

were located at (KBr) 3080 (w), 3020 (w), 2980 (w), 2960 (w), 1800 (s),

1750 (s), 1730 (s), 1720 (w), 1590 (w), 1500 (m), 1460 (m, sh), 1415

(s), 1365 (m), 1320 (m), 1260 (s), 1240 (s), 1170 (s), 1135 (m),










1080 (w), 1030 (w), 990 (w), 930 (w), 830 (w), 760 (n), 720 (w),

680 (w), 640 (w), and 620 (w) cm.-. The molecular ion was found at

275 m/e in the mass spectrum.

Anal. Calcd. for C3 H 2N30 : C, 56.73; H, 4.75; N, 15.27.

Found: C, 56.83; H, 4.80; N, 15.33.

l-FormvylTethl -2-chloroacetyl-4-phenl-l ,2,4-triazoiine-3 5-

dione, 55, precipitated upon pouring the reaction mixture into 250 ml.

of stirred hexane. Nuclear magnetic resonance analysis of the crude

material indicated no copolymer formation. Purification was effected

by twice recrystallizing the crude product from hexane-methylene chloride

yielding 0.80 g. (95%) of product, m.p. 157-1580. The infrared spectrum

exhibited absorbances at (KBr) 3030 (w), 3010 (w), 2990 (w), 2880 (w),

2745 (w), 1810 (s). 1760-1710 (s, b), 1600 (w), 1510 (s), 1430 (s),

1400 (m), 1330 (m), 1330 (m), 1310 (w), 1240 (m), 1210 (m), 1190 (m),

1120 (m), 1090 (m), 1070 (m), 1020 (m), 960 (w), 920 (w), 880 (w),

860 (w), 820 (w), 780 (m)- 760 (m), 740 (m), 700 (s), 650 (m), and

620 (m). The molecular ion was located at 295 m/e in the mass spectrum.

Anal. Calcd. for C 2H oCN 04: C, 48.91; H, 3.42; H, 14.26.

Found: C, 49.00; H, 3.58; N, 14.20.

l-Formylmethyl-2-benzoyloxy-4-phenyl-1,2,4-triazoline-3,5-dione,

57, and 3-phenyl-6-benzoyloxy-l,3,5-triazabicyclo[3.2.0]hepta-2,4-dione,

58, could not be separated by fractional crystallization or column

chromatography using alumina and methylene chloride as the eluent.

Their structural assignments were made based upon the nuclear magnetic

resonance spectrum of the mixture, total yield 0.11 g. (13%).

l-Fornmylmethvl-2-(2-methvylropionvl)-4-phenyl-1,2, -triazoline-

3,5-dicne, 60, and 3-phenyl-6-(2-methvlDropionyloxy)-l,3,5-triaza-










bicyclc[3.2.0]hepta-2,4-dione, 61, appeared as an oil after evaporation

of the solvent. The mixture was dissolved in the minimum amount of

methylene chloride necessary to attain solution followed by addition

of the minimum amount of hexane to cause cloudiness. The solution was

allowed to stand at room temperature for two to three days, resulting

in fractional crystallization (61 crystallized first) of the solids.

The procedure was repeated several times in order to obtain a pure

sample of 60. The data for 60 are as follows: yield 0.50 g. (60%);

m.p. 100-101; infrared (KBr) 3040 (w), 3000 (w), 3870 (w), 2750 (w),

1800 (s), 1735 (s, b), 1720 (s, sh), 1600 (w), 1500 (m), 1460 (s),

1420 (s), 1380 (m), 1350 (m), 1260 (m), 1200 (m), 1180 (m), 1100 (m),

1080 (w), 1020 (w), 950 (w), 890 (w), 860 (w), 840 (w), 790'(w),

750 (w), 740 (w), 690 (w), 640 (w), and 620 (w) cm.-1; molecular ion

at 289 m/e; anal. calcd. for CH 15N304: C, 58.13; H, 5.23; N, 14.53.
15 l5 3 14

Found: C, 58.29; H, 5.36; H, 14.45. The data for 61 are as follows:

yield 0.50 g. (6.3%); m.p. 163-16L,; infrared (KBr) 3049 (w), 3040 (w),

2990 (w), 2940 (w), 2890 (w), 1780 (m), 1755 (s), 1720 (s), 1600 (w),

1500 (m), 1460 (m), 1410 (s), 1380 (m), 1360 (m), 1340 (m), 1295 (w),

1265 (m), 1240 (m), 1190 (m), 1140 (s), 1110 (m), 1060 (m), 1020 (m),

960 (w), 920 (w), 870 (w), 840 (w), 810 (w), 770 (m), 740 (m), 690
-i
(m), 670 (w), and 620 (w) cm. ; molecular ion at 289 m/e; anal. calcd.

for C 4H 1N3 0: C, 58.13; H, 5.23; N, 14.53. Found: C, 58.00; H,

5.31; M, 14.36.

1-Formylmethvl-2-(2,2-dimethylpropionyl)-4-phenyl-1,2,4-triazoline-

3,5-dione, 63, and 3-phenyl-6-(2,2-dimethylpropionyl)-1,3,5-triaza-

bicyclo[3.2.0]hepta-2,4-dione, 64, were purified using the same proce-

dure employed for 60 and 61, substituting hexane-ether as the solvent










pair. The data for 63 are as follows: yield 0.31 g. (36%); m.p.

135-1360; infrared (KBr) 2990 (w), 2880 (w), 2740 (w), 1780 (m),

1740 (s), 1720 (s), 1700 (s), 1600 (w), 1500 (m), 1420 (s), 1400 (m),

1370 (in), 1330 (rm), 1270 (m), 1220 (m), 1180 (m), 1110 (m), 1090 (w),

1070 (w), 1010 (w), 940 (w), 870 (w), 840 (w), 820 (w), 770 (w), 760

(w), 730 (w), 690 (w), and 640 (w); molecular ion at 303 m/e; anal.

calcd. for C15H 7N304: C, 59.40; H, 5.65; N, 13.85. Found: C, 59.30;

H, 5.79; N, 13.79. The data for 64 are as follows: yield 0.31 g.

(36%0; m.p. 171-172; infrared (KBr) 3100 (w), 2990 (w), 2900 (w),

1780 (m), 1750 (s), 1725 (s), 1600 (w), 1500 (m), 1480 (w), 1460 (w),

1410 (m), 1360 (w), 1290 (w), 1280 (w),. 1250 (w), 1130 (m), 1080 (w),

1050 (w), 1030 (w), 870 (w), 770 (w), 740 (w), 690 (w), and 640 Cw)
-i
cm. ; molecular ion at 303 m/e; anal. calcd. for C H N 0 : C, 59.40;
15 17 3 4

H, 5.65; N, 13.85. Found: C, 59.18; H, 5.70; N, 13.89.


Attempted reaction of vinyl trifluoroacetate

Vinyl trifluoroacetate was allowed to stand with PhTAD for 96 hours

at 600. Approximately 80% of PhTAD was recovered unreacted along with

10% of a tan solid, which appeared to be an oligomeric decomposition

product of PhTAD by comparison of its infrared spectrum with the

spectrum of a known sample.61


Procedure for kinetic measurements

One ml. portions of equimolar solutions of vinyl ester and PhTAD

in 1,1,2,2-tetrachloroethane were pipetted into a pressure resistant

ultraviolet cell. Visible spectra were recorded and the PhTAD absorbance

at 545 nanometers was measured versus time. A minimum of seven readings

were taken during each run. The reaction was determined to be second











order overall by fitting the data in the second order rate expression

(equation 4), which assumes formation of the 1,4-dipole to be irrever-

sible. The reaction was determined to be first order in each reactant

A absorbancee, time t
a =PhTAD absorptivity
equation 4 k i coefficient X cell path
equation t -t
A a A length
k =second order rate constant
A =initial absorbance
0

by noting a ten fold increase in rate when using a ten to one molar

ratio of vinyl ester to PhTAD, indicating the reaction to be first

order in vinyl ester. The results were double checked by fitting the

ten to one molar ratio data in the first order rate expression

(equation 5) demonstrating the reaction to be pseudo first order in

PhTAD under these conditions. Energies of activation, calculated by

At
-t
equation 5 in -- = kt + A k = first order rate constant
a o


the Arrhenius method, are listed to three significant figures in

Table X. Second order rate constants measured at temperatures

other than 600 are reported also. Entropies of activation were

calculated by use cf equation 3 (described in section "B", Chapter II).


Procedure used for checking thermal stability of 64

A sample of the solid resulting from reaction of PhTAD and vinyl

pivalate was dissolved in chloroform-dl and its nuclear magnetic

resonance spectrum taken. The spectrum appeared as a superimposition

of the spectra of the three pure products. Of special note was the

ratio (1.2:1.0) of the r-butyl singlets of the monomeric products, one

at 61.37 corresponding to the t-butyl group of 63, the other at 61.20











Table X

Kinetic Data for the Vinyl Ester/PhTAD Reactionsa

Measured at Various Temperatures


Vinyl Ester

Isopropenyl Acetate




Vinyl Acetate





Vinyl Isobutyrate





Vinyl Pivalate





Vinyl Chloroacetate






Vinyl Benzoate


Temp., OC k, Z/mn -sec(C of C)b AEact, Kcal/moi
Teiro., C k, Z,/mol-sec(C of C) act'


34.8

40.6
48.1

44.5
68.3

74.9

69.7
78.8
90.0

51.1

73.1
80.2

71.3
78.3

90.0
101.5

62.5
69.0
75.7
80.0


1.0 X 10-1
1.5 X 10-1
2.0 X 10-

1.7 X 10-2 (0.998)
6.1 X 10-2

9.1 X 10-2

9.9 X 10-2

1.8 X 10-1
-1
2.5 X 0101 (0.998)

2.6 X 10-2

8.5 X 10-2
1.2 X 10-1

1.8 X 10-2
2.7 X 10-2
5.0 X 10-2
9.0 X 10-2

3.8 X 10-2

5.7 X 10-2
7.2 X 10-2
8.4 X 10-2


7.44





11.9





11.6





12.1





13.6






10.7


aSince the third decimal place in the absorbance

these values are accurate to two decimal places

Table I.

Coefficient of correlation, as in Table VII.


readings was estimated,

only, as reported in











caused by the t-butyl group of 64. The nuclear magnetic resonance

tube was heated at 600 for sixteen hours followed by spectral analysis.

No change in the t-butyl ratio occurred, and there was no noticeable

increase in copolymer; thus, it was concluded that the 1,2-diazetidine,

64, did not ring open.


Reaction of l-fornyl-2-acetyl-4-phenyl-l,2,4-triazoline-3,5-dione, 34

and ethanol acetal formation

l-Formyl-2-acetyl-4-phenyl-l,2,4-triazoline-3,5-dione, 34,

(0.00383 mol., 1.000 g.) was added to 50.0 ml. absolute ethanol in

a 100 mi. round bottomed flask. A small crystal of toluenesulfonic

acid was added along with 30.0 g. of anhydrous Na2SO4, and the mixture

was refluxed for one half hour. The solution was allowed to stand

overnight, after which the solid Na2 S was filtered and the filtrate

evaporated yielding a light yellow oil (0.988 g., 91%),identified by

nuclear magnetic resonance as l-(l,l-ethoxy-2-ethyl)-2-hydro-4-phenyl-

1,2,4-triazoline-3,5-dione. Apparently the acetoxy group at the "2"

position was cleaved under the reaction conditions. Nuclear magnetic

resonance signals were found at (CDC1,) 61.21 (t, 6), 63.65 (m, 6),

64.80 (t, 1), 66.64 (broad singlet, 1 (N-H proton)), and 67.48 (s, 5).

The attempted vacuum distillation of the light yellow oil to obtain

an analytically pure sample resulted in decomposition of the acetal.












E. Bis-Triazoline-dione Copolymerizations

Synthesis of bis-(p-3,5-dioxo-1,2,4-triazolin-4-ylphenyl)methane, 6952

A 100 ml. solution of bis-(4-isocyanatophenyl)methane (0.100 mol.,

24.0 g.), vacuum distilled before use, was slowly added to a 200 ml.

solution of ethyl carbazate (0.200 mol., 19.0 g.) in benzene, which

was cooled to maintain the temperature at 450 or below. After the

addition was complete, the mechanically stirred mixture was refluxed

for one half hour to insure complete reaction. The resulting insoluble,

white solid was filtered, and dried after stirring overnight. The

bis-semi-carbazide, 67, melted at 236-2450 (lit.52 240-2440) and

weighed 40.1 g. (93%).

The bis-semicarbazide (0.087 mol., 40.0 g.) was slowly added

to a 100 nl. 'IK aqueous solution of potassium hycroxide and 100 ml.

ethanol. The mixture was heated on a steam bath for two hours followed

by filtration of a small amount of insoluble solid. The light yellow

filtrate was slowly added to an excess of 5% aqueous acetic acid,

precipitating the bis-urazole, 68, an off-white solid, m.p. 3250

(decomposition), (lit.52 3200). The yield was 34.9 g. (95%).

The bis-urazole (0.095 mol., 34.9 g.) was suspended in 50 ml.

methylene chloride by magnetic stirring and cooled to -100, followed

by the addition of 1.0 ml. of fuming nitric acid over a 10 minute

period. A red color was immediately generated during the addition,

and the solution was allowed to stir for 5 minutes after the addition.

The solution was washed with 200 ml. cold water, dried cold over

sodium sulfate, and evaporated to dryness at reduced pressure (.5-10 mm.)

below room temperature. The red solid that resulted was dissolved










in 15 ml. ethyl acetate, filtered, and slowly added to 150 ml. low

boiling petroleum ether causing precipitation of the bis-triazoline-

dione, 69. The procedure was repeated twice to insure purification

yielding 16.9 g. (70%) of product. The red solid did not melt, but

changed color to tan at 3350 (lit.52 3200).

Anal. Calcd. for C 7H oN604: C, 56.36; H, 2.98; N, 23.20.

Found: C, 56.47; H, 2.90; N, 22.63.


Synthesis of 1,6-hexane-bic-l,2,4-triazoline-3,5-dione, 73

Freshly distilled 1,6-hexanediisocyanate (0.238 mol., 40.0 g.)

was dissolved in 10 ml. benzene. This solution was dropped slowly

into a solution of ethyl carbazate (0.476 mol., 49.5 g.) in 200 ml.

benzene. The diisocyanate was added at room temperature, and the rate

of addition was controlled to maintain the temperature at 300 or below.

After the addition was complete, the voluminous white slurry was

stirred at room temperature for one half hour, then refluxed gently

for two hours. The bis-semicarbazide, 70, was removed by vacuum

filtration and then dried under vacuum at 500 overnight, yielding

88.0 g. (98%) of product, m.p. 201-2030. Infrared absorbances were

observed at (KBr) 3380 (s), 3305 (s, b), 1735 (s), 1685 (s), 1450 (m),

1400 (m), 1370 (w), 1310 (m), 1225 (s), 1110 (w), 1095 (w), 900 (w),

850 (w), 760 (m), and 615 (m) cm.-. Nuclear magnetic resonance

signals were found at (DMSO-d ) 61.06 (t, 6, J 7 Hz. ), 61.17 (m, 8),

62.87 (m, 4), 63.92 (q, 4, J 7 Hz. ), 66.10 (distorted triplet, 2),

67.50 (broad singlet, 2), and 68.40 (broad singlet, 2).

Anal. Calcd. for C 14H 281T0 C, 44.67; H, 7.50; N, 22.33.

Found: C, 44.82; H, 7.60; N, 22.39.










Sodium hydride (1.59 mol. equiv. Na, 7.65 g. of 50% oil disper-

sion), was slowly added to 750 ml. absolute ethanol. After complete

evolution of hydrogen, the solution was filtered and poured over the

bis-semicarbazide, 70, (0.0797 mol., 30.0 g.) in a 1-liter 3-necked

found bottomed flask. The slurry was stirred mechanically and refluxed

for 24 hours. A light brown solid, 16.7 g. (75%) was filtered and

dried overnight under vacuum at 150. A portion of this solid (m.p.

3100) was dissolved in water and neutralized with 50% HC1 until a pH

of 7 was attained. The clear solution was placed in a freezer at

-100 resulting in low yield precipitation of 1,6-hexane-diurazole,

72. The offwhite solid melted in a range of 211-2160. Infrared

absorbances were found at (KBr) 3700-3100 (m, very broad), 3310 Cm,

shoulder), 2950 (w), 1690 (s, b), 1470 (m), 1430 (w), 1360 (w), 1330

(w), 1180 (w), 1080 (w), 970 (w), 850 (w), 790 (m), 720 (w), and 64u

(w) cm.-. Nuclear magnetic resonance signals were observed at (DMSO-

d ) 61.48 (m, 8), 63.48 (distorted triplet, 4), and 610.07 (broad, 4).

Anal. Calcd. for CoH N 604 C, 42.25; H, 5.67; N, 29.56.

Found: C, 42.25; H, 5.86; N, 29.33.

Sodium sulfate (anhydrous, 25.0 g.) was added to 300 ml. methylene

chloride, and the magnetically stirred slurry was cooled to 5. The

diurazole, 72, (or the light brown solid, presumably the diurazole

salt) (0.0176 mol., 5.00 g.) was added and dinitrogen tetroxide was

bubbled slowly through the stirring slurry until a dark reddish-purple

color persisted (about 30 minutes). The sodium sulfate was removed

by filtration and the dard red filtrate was evaporated on a rotary

evaporator using lukewarm water. A light pink solid remained as a

residue, which was dissolved in 20 ml. of ethyl acetate. The red











solution was filtered, then slowly dropped into 200 ml. petroleum

ether (b.p. 20-400) resulting in the precipitation of a light pink

solid weighing 3.4 g. (70%), identified by analysis to be the desired

bis-triazoline-dione, 73. The product was dried in the dark overnight

after filtration. The solid decomposed at 170-1750. Infrared

absorbances were found at (KBr) 2920 (w), 1770 (m), 1735 (s, b), 1520

(w), 1430 (w), 1380 (m), 1340 (w), 1310 (w), 1240 (w), 1180 (w), 1110

(w), 710 (w), and 660 (m) cm. -. Nuclear magnetic resonance signals

were observed at (DMSO-d ) 61.43 (m, 8) and 63.43 (distorted triplet,

4).

Anal. Calcd. for C1 H 1604 : C, 42.86; H, 4.32; N, 29.99.

Found: C, 42.58; H, 4.51; N, 29.83.


Attempted cvclization of 70 usinF rotcssium hydroxide

In an attempt to generate the diurazole, 72, by normal procedure,

the bis-semicarbazide (0.106 mol., 40.0 g.) was slowly added to 250 ml.

4K solution of potassium hydroxide on a steam bath. The bis-semi-

carbazide went into solution as before, requiring more time, however.

The solution was filtered hot, then diluted with an additional 200 ml.

distilled water. The light yellow solution was neutralized with 50%

HC1. When the pH approached 7, a gas began to evolve, and at a pH

of 7, large amounts of the gas were produced upon addition of small

quantities of acid. No precipitate appeared as had been observed in

the synthesis of other urazoles. A sample of the gas was trapped,

and its infrared spectrum measured; infrared absorbances were located

at (gas cell) 3760 (w, sharp), 3740 (w, sharp), 2340 (s), 670 (m),

and 650 (m, shoulder)cm.-1. Since the gas was thought to be C02,

a sample of CO, was generated by acidifying an aqueous solution of










CaCO3. The infrared spectrum of this gas was identical to the gas

evolved in the attempted cyclization reaction, with infrared absor-

bances being attributed to the presence of CO and water vapor; thus,

71 was proposed as the product of the attempted cyclization rather

than 72.

Efforts to effect the cyclization of 70 in alcoholic potassium

hydroxide also led to the proposed structure 71, rather than the

diurazole, 72.


Synthesis of 80, a model compound for the 1,4-dipole intramolecular

rearrangement copolvmerizations

1,6-Hexane-bis-1,2,4-triazoline-3,5-dione, 73, (0.00125 mol.,

0.351 g.) was dissolved in 20 ml. tetrahydrofuran and was slowly

added to a 20 ml. solution of isopropenyl acetate (0.00251 mol.,

0.251 g.). The red solution was stirred magnetically at room tem-

perature overnight. The following morning the solution was light

yellow indicating that the reaction was complete. The solvent was

evaporated, and the residue weighing 0.500 g. (83%) was dried at

58/0.03 mm. overnight. Nuclear magnetic resonance signals were found

at (DMSO-d6) 61.43 (m, 8), 62.13 (s, 6), 62.53 (s, 6), 63.62 (distorted

triplet, 4, J=6 Hz. ), and 64.82 (s, 4), which was consistent with

the assigned structure, 80.


Synthesis of 81, a model compound for the 1,4-dipole intramolecular

rearrangement copol'n.erizations

4-Nethyl-l,2,4-triazoline-3,5-dione, 8 (0.00254 mol., 0.287 g.)

was dissolved in 20 ml. tetrahydrofuran and was slowly added to a











20 ml. solution of the diisopropenyl ester of adipic acid, 74 (0.00127

mol., 0.257 g.). The red solution was stirred magnetically overnight

resulting in discharge of the red color to light yellow. The solvent

was evaporated, and the residue weighing 0.490 g. (90%) was dried at

580/0.03 mm. overnight. Nuclear magnetic resonance signals were

observed at (DMSO-d ) 61.60 (m, 4), 62.12 (s, 6), 62.90 (m, 4),

62.92 (s, 3), 63.18 (s, 3), and 64.72 (s, 4), which was consistent

with tne assigned structure, 81.


Synthesis of diisopropenyl adipate, 7470

To a one-necked three liter flask containing siopropenyl acetate

(3.09 mol., 309.0 g.) was added adipic acid (0.772 mol., 113 g.).

The flask was equipped with a mechanical stirrer, a thermometer, and

a reflux condenser, and the stirred solution was heaLed to 96-99'

for 48 hours. During this period a homogeneous yellow solution was

attained. The solution was allowed to cool and was then washed

with 100 ml. of a cold, saturated Na2CO3 solution to neutralize the

acetic acid. The solution was washed with additional, smaller portions

until no further CO2 was released. The light yellow solution was then

stored over 100 g. anhydrous Na2SO4 for four days. The solution was

then vacuum distilled through a fractionating column collecting the

fraction boiling between 950 and 1050/0.75 mm. The clear, colorless

liquid was placed on an alumina column one inch in diameter and six

inches long, and washed through with low boiling (20-400) petroleum

ether. Five 20 ml. samples were collected. The low boiling ether

was evaporated on a rotary evaporator leaving a clear, colorless

liquid, identified as the desired product, 74, behind. Nuclear










magnetic resonance signals were located at (CDC13) 61.69 (m, 4),

61.90 (s, 6), 62.32 (m, 4), and 64.61 (broad singlet, 4). The refract-

ive index at 260 was 1.4481. The total yield for the reaction was

18.9 g. (12%).

'71
Synthesis of divinyl adipate, 757

Freshly distilled vinyl acetate (3.22 mol., 278.0 g.) was placed

in a 500 ml. round bottomed 3 necked flask equipped with a reflux

condenser, a mechanical stirrer and a thermometer. Adipic acid (0.204

mol., 30.0 g.) was then added along with 1.0 g. Hg (OAc)2, 50 mg. Cu

powder, and 0.2 ml. H2SO4. The mixture was refluxed for 12 hours.

After this period, metallic mercury had appeared, and the solution

had turned dark green. The solution was allowed to cool, and 0.8 g.

NaAc was added. The mixture was transferred to a 500 ml round bottomed

flask, and the excess vinyl acetate and acetic acid was removed on

a rotary evaporator. The residual solution was transferred to a

100 ml. round bottomed flask, and the mixture was vacuum distilled

through a fractionating column collecting the fraction boiling between

900 and 1200/2 mm. The clear, colorless liquid was redistilled on

a spinning band distillation column, and the fraction boiling at 105--

1100/2 mm. was collected and identified as the desired product, 75.

The refractive index at 260 was 1.5515. Nuclear magnetic resonance

signals were observed at (CDC 3) 61.65 (m, 4), 62.39 (m, a), 54.7 (m, 4),

and 67.2 (L signals, 2). Since the nuclear magnetic resonance spectrum

was as described in the literature, no further purification was necessary.

The total yield of the reaction was 27.9 g. (49%).











Attempted synthesis cf diisopropenyl tetechthalate

Terephthalic acid (0.772 mol., 128.0 g.) was added to diisopropenyl

acetate (3.09 mol., 309.0 g.) in a 1 liter, 3-necked flask equipped

with a mechanical stirrer, a thermometer, and a reflux condenser.

Hg(OAc)2 (3.0 g.) was added to catalyze the reaction, and the hetero-

geneous mixture was maintained at 96-990 for 48 hours. No reaction

occurred. After adding 20 drops of H2S04, the mixture was once again

refluxed at 96-990. A very dark solution resulted after 48 hours,

which solidified after cooling; apparently, the isopropenyl acetate

homopolymerized as evidenced by the very broad signals in the nuclear

magnetic resonance spectrum of the solid.

Dimethyl terephthalate (0.500 mol., 89.0 g.) was mixed with di-

isopropenyl acetate (3.09 mol., 309.0 g.) in a 1 liter, 3-necked

flask equipped with a mechanical stirrer, a thermometer, and a reflux

condenser. A homogeneous solution resulted which was heated to 850

for 48 hours. During this time, the solution turned very dark yellow.

In attempting to fractionate the solution under vacuum, the liquid

became highly viscous after the excess isopropenyl acetate distilled,

and no further liquid came over. No further purification was attempted.


Copolymerization of 73 and 74 at room temperature

Diisopropenyl adipate, 74, (0.002144 mol., 0.4335 g.) was dissolved

in 15 ml. tetrahydrofuran, and was slowly added to a 20 ml. solution

of the bis-triazoline-dione, 73 (0.002144 mol., 0.6007 g.). The

solution was placed in a thick-walled glass tube, degassed by two

liquid nitrogen freeze-thaw cycles, and sealed under vacuum. The red

solution was allowed to stand overnight resulting in the discharge











of the red color and the formation of a light yellow gel. The gel

was filtered and washed with cold solvent, followed by drying overnight

at 58/0.03 mm., giving a light yellow solid weighing 0.848 g. (82%).

The solid was found to be insoluble in methylene chloride, chloroform,

acetone, petroleum and ethyl ether, tetrahydrofuran, hexane, water,

ethanol, methanol, ethyl acetate, nitromethane, benzene, hexamethyl-

phcsphoritriamide, and N-methylpyrrolidone. The solid was observed

to swell considerably in dimethyl sulfoxide and dimethylformamide.

The solid did not melt or soften at temperatures up to 2500; instead,

it slowly darkened if left at temperatures greater than 2000 for more

than 15 minutes. Infrared absorbances were observed at (KBr) 3500

(m, b), 3300 (m, b), 2980 (m), 2900 (w), 1800 (m, shoulder), 1730

(s, b), 1460 (s), 1430 (s), 1370 (m, b), 1340 (m), 1220 (m, b), 1180

(m), 1130 (w), 1000 (w), 770 (w), and 680 (w) cm.-1. A 0.200 g.

sample was heated to 600 for 5 hours in dimethylsulfoxide-d dissolving

10% of the solid. A nuclear magnetic resonance spectrum was recorded,

and very broad nuclear magnetic resonance signals were observed at

(DMSO-d6) 61.8, 62.9, 63.5, and 64.7. Relatively sharp nuclear

magnetic resonance signals were located at 61.8 and 63.5, which were

thought to be due to the solvent, tetrahydrofuran. The nuclear magnetic

resonance solution was slowly added to 10 ml. of water, causing pre-

cipitation of a light yellow solid. Infrared analysis gave a spectrum

almost identical to the original insoluble solid.

Anal. Calcd. for a 1:1 copolymer, C22H30N60s: C, 52.17; H, 5.97;

N, 16.59. Found: C, 53.98; H, 6.34; N, 15.04.

The light yellow liquid, separated from the gel by filtration,












was slowly added to 200 ml. of hexane precipitating 0.083 g. (8%)

of a light yellow solid. The solid softened around 1100, and was

soluble in methylene chloride, chloroform, dimethylsulfoxide,

dimethylformamide, and acetone. Infrared analysis (KBr) gave

absorbances at 3500 (m, b), 3300 (m), 2980 (m), 2880 (w), 1780

(m), 1730 (s, b), 1460 (s), 1430 (s), 1370 (m, b), 1330 (m, b),

1220 (m, b), 1180 (m), 1120 (w), 1010 (w), 770 (m), and 670 wC) cm.-1

Vapor pressure osmometry in acetone gave a number average molecular

weight of 1780. Nuclear magnetic resonance signals were found at

(DMSO-d6) 61.5 (broad multiplet, 61.7 (broad multiplet, 62.1

(s), 63.0 (broad multiplet, 63.6 (broad multiplet, and 64.8 Cs).

Anal. Calcd. for a 1:1 copolymer: C22H30N608: C, 52.17;

H, 5.97; N, 16.59. Found: C, 52.42; iH 6.01; N, 16.35.


Copolymerization of 73 and 74 at 600

Diisopropenyl adipate, 74 (0.002047 mol., 0.4141 g.) was dissolved

in 15 ml. tetrahydrofuran, and was slowly added to a 20 ml. solution

of the bis-triazoline-dione, 73 (0.002047 mol., 0.5737 g.). The

procedure used for copolymerization was the same as for the room

temperature reaction, and the results were almost identical. The

yield of insoluble gel was 0.839 g. (85%).

Anal. Calcd. for a 1:1 copolymer C22H30N608: C, 52.17; H, 5.97;

N, 16.59. Found: C, 53,86; H, 6.39; N, 15.25.

The yield of soluble copolymer was 0.059 g. (6%).

Anal. Calcd. for a 1:1 copolymer, C22H30 608: C, 52.17, H, 5.97;

N, 16.59. Found: C, 51.90; H, 6.07; I, 16.59.











Copolynerization of 69 and 7E at room temperature

Divinyl adipate, 75, (0.000829 mol., 0.164 g.) was dissolved

in 15 ml. of tetrahydrofuran. This solution was added to a 20 ml.

solution of the bis-triazoline-dione, 69, (0.000829 mol., 0.300 g.),

and the red solution was degassed by two liquid nitrogen freeze-thaw

cycles, then sealed under vacuum. The solution was allowed to stand

at room temDerature until the characteristic red color of 69 had

changed to light yellow, a period of two days. During this time a

light yellow gel formed. The tube was opened, and the gel was

filtered, washed twice with cold tetrahydrofuran, and dried at 580/

0.03 mm. overnight yielding 0.380 g. (82%) of product. The light

yellow solid was insoluble in chloroform, acetone, benzene, methylene

chloride, tetrahydrofuran, nitromethane, 1,4-dioxane, ethyl acetate,

carbon disulfide, water, acetonitrile, or hexamethylphosphorictriamide.

Swelling was noted when the solid was brought into contact with

dimethylformamide and dimethylsulfoxide. No melting or softening

was observed up to 2500; however, the solid did darken in color when

exposed to temperatures greater than 2000 for more than 20 minutes.

Infrared absortances were observed at (KBr) 3450 (m, b), 3300 (m, b),

2950 (w, b), 1800 (m), 1720 (s, b), 1610 (w), 1600 (w), 1510 (m),
-i
1420 (m, b), 1350 (w), 1220 (w), 1130 (w), 1020 (w), and 750 (w) cm.-1

A 0.200 g. sample was heated to 600 for five hours in dimethylsulfoxide-

d dissolving 12% of the solid, and nuclear magnetic resonance analysis

gave very weak and broad signals at (DMSO-d ) 61.7, 63.2, 64.2, 64,7

(barely discernible), and 67.4. The region of the spectrum where an











aldehyde signal would have been expected 9-106 was carefully

examined and there was no conclusive evidence for its existence.

This sample was slowly added to 10 ml. of water precipitating a

light yellow solid whose infrared spectrum was almost identical to

that of the original solid.

Anal. Calcd. for a 1:1 copolymer, C27 H2460 : C, 57.86; H, 4.32;

N, 14.99. Found: C, 55.81; H, 4.43; N, 16.08.

The light yellow liquid, separa.Led from the gel by filtration,

was slowly added to 200 ml. of stirred hexane precipitating 0.041 g.

(9%) of a light yellow solid, which softened around 120. The solid

was soluble in methylene chloride, chloroform, acetone, acetonitrile,

tetrahydrofuran, carbon disulfide, and ethyl acetate. Vapor pressure

csmometry in acetone gave a number average molecular weight of 1510.

Infrared abscrbances were found at (KBr) 3500 (m, b), 3300 (m, b), 2980

(w), 1800 (m), 1730 (s, b), 1510 (w), 1600 (w), 1540 (w), 1500 (m),

1420 (m), 1350 (m), 1210 (w), 1130 (m), 1010 (w), and 750 (w) cm.-1

Nuclear magnetic resonance signals were observed at (DMSO-d5) 61.7

(m), 62.9 (m), 63.4 (m), 64.1 (s, broad), 67.4 (s, broad), and 69.2

(s, broad).

Anal. Calcd. for a 1:1 copolymer, C27H 24 60 : C, 57.86; H, 4.32;

N, 14.99. Found: C, 57.00; H, 4.92; N, 14.39.


Cooolvnerization of 59 and 75 at 60

Divinyl adipate, 75, (0.000472 mol., 0.0934 g.) was dissolved

in 10 ml. tetrahydrofuran and slowly added to a 15 ml. solution of

the bis-triazoline-dione, 69 (0.000472 mol., 0.171 g.). The procedure











used for copolymerization was the same as for the room temperature

reaction and the results were almost identical. The yield of insoluble

gel was 0.216 g. (82%).

Anal. Calcd. for a 1:1 copolyner, C27H 2460 : C, 57.86; H,

4.32; N, 14.99. Found: C, 55.99; H, 4.41; N, 16.14.

The yield of the soluble copolymer was 0.020 g. (9%).

Anal. Calcd. for a 1:1 copolymer, C27H 0 : C, 57.86; H,
27 24 1608; C, 57.86; H,

4.32; i!, 1i.99. Found: C, 57.14; H, 4.81; N, 14.45.


Copolymerization of 69 and 74 at room temperature

Diisopropenyl adipate, 74, (0.00178 mol., 0.3605 g.) was dissolved

in 15 mi. tetrahydrofuran and was slowly added to a 20 ml. solution

of the bis-triazoline-dione, 69 (0.00178 mol., 0.644 g.). The red

solution was placed in a heavy-walled glass tube, and the sample

was degassed by two liquid nitrogen freeze-thaw cycles. The sample

was sealed under vacuum and allowed to stand overnight causing

discharge of the red color and formation of a light yellow gel

saturated with a light yellow liquid. The gel was filtered, washed

twice with cold tetrahydrofuran, and dried overnight at 580/0.03 mm.

yielding 0.813 g. (81%) of a light yellow solid. The solid was

insoluble in ethyl ether, petroleum ether, hexane, terrahydrofuran,

water, ethanol, methanol, ethyl acetate, benzene and hexamethylphos-

phcrictriamide. Swelling of the solid was observed when in contact

with dimethylformamide or dimethylsulfoxide. As before, the solid

did not melt up to 2500, but discolored when allowed to stand at

temperatures greater than 200 for more than 20 minutes. Infrared







91.


absorbances were found at (KBr) 3500 (m, b), 3300 (m, b), 3080 (w),

2980 (w), 1800 (m), 1730 (s, b), 1600 (w), 1500 (m), 1420 (m), 1340
-l
(m), 1200 (w), 1000 (w), and 760 (w) cm.1. A 0.200 g. sample was

heated to 600 fcr 10 hours in dimezhylsulfoxide-d6, dissolving less

than 2% of the solid. The light yellow solution was so dilute that

the attempted nuclear magnetic resonance analysis gave no information

with the exception of two small signals at 61.8 and 63.6, which were

assigned to the solvent, tetrahydrofuran.

Anal. Calcd. for a 1:1 copolymer, C29H2 8N08: C, 59.18; H, 4.80;

N, 14.28. Found: C, 60.41; H, 4.10; N, 13.32.

The light yellow liquid, separated from the gel, slowly was added

to 250 ml. of stirred hexane precipitating 0.082 g. (8%) of a light

yellow solid which softened around 100. The solid was soluble in

methylene chloride, chloroform, acetone, tetrahydrofuran, carbon

disulfide, and ethyl acetate. Vapor pressure osmometry in acetone

gave a number average molecular weight to 1430. Infrared absorbances

were found at (KBr) 3500 (m, b), 3300 (m, b), 2980 (w), 1800 (m),

1720 (s, b), 1600 (w), 1500 (m), 1440 (w), 1200 (w), 1000 (w),

and 750 (w) cm.-1. Nuclear magnetic resonance signals were found

at (CDC13) 61.5 (m), 62.1 (s), 63.0 (m), 64.1 (s), 64.8 (s), and

67.4 (m, broad).

Anal. Calcd. for a 1:1 copolymer, C29H28N608: C, 59.18; H, 4.80;

N, 14.28. Found: C, 58.84; H, 4.81; N, 14.04.


Copolnmerization of 69 and 74 at 60

Diisopropenyl adipate, 74 (0.00201 mol., 0.41407 g.), was dissolved

in 15 ml. tetrahydrofuran and was slowly added to a 20 ml. solution of




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