Preparation of polymers via Manninch reaction

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Preparation of polymers via Manninch reaction
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Hong, Seok Heui, 1952-
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Polymers and polymerization   ( lcsh )
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Chemistry thesis Ph. D
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Thesis:
Thesis (Ph. D.)--University of Florida, 1985.
Bibliography:
Bibliography: leaves 110-112.
Statement of Responsibility:
by Seok Heui Hong.
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Typescript.
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Vita.

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PREPARATION OF POLYMERS
VIA MANNICH REACTION






BY






SEOK HEUI HONG -


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN
PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY


UNIVERSITY OF FLORIDA


1985
























To my family, for their love,

patience and encouragement















ACKNOWLEDGMENTS


I wish to extend my sincere appreciation to Dr. George B. Butler

for his help, advice and expertise during my program of research. I

would also like to thank the members of my supervisory committee.

Colleagues, members of the polymer research group, are

appreciated for the friendly atmosphere they provided. I also thank

Ms. Cindy Zimmerman for her skillful typing of this manuscript.

Finally, I would like to thank Mr. S.H. Yoon and Mr. M. Murla for

their help.

Financial support for this work from the Department of

Chemistry, Graduate School, International Minerals and Chemical

Corporation, Allied Chemical Company and National Institute of Health

is gratefully acknowledged.















TABLE OF CONTENTS


Page
ACKNOWLEDGMENTS.................................................iii

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

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

ABSTRACT...................................................... .......... ix

CHAPTERS

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

The Use of Amines.............................................3
Nitroalkanes.................................. ....... 5
Polymeric Mannich Bases..................................7
Proposal of Research.....................................8

II EXPERIMENTAL...........................................13

General ..................................... ...... ..... .13
Reagents and Solvents...................................14
Synthesis of Nitroalcohols.............................15
Synthesis of Model Compounds............................20
Reactions Utilizing Chain-Stopping Reagents.............32
Synthesis of Polymers..................................33
Reduction of Model Compounds...........................39
Reduction of Polymers.................................41
Methylation............................................43
Miscellaneous Reactions...............................46

III RESULTS AND DISCUSSION.................................52

Model Compounds.......... .............................56
Model Compounds with 2-Nitropropane as
Chain-Stopping Reagent..........................62
Model Compounds with N-(B-hydroxyethyl)
Piperazine.................................... 71
Studies with Nitromethane..........................80
Model Compounds from Bis-secondary Amines..........81
Polymers ........ ...................88










Reduction of Model Compounds............................94
Reduction of Polymers...................................99
Methylation........................... .. ... ......103
Mannich Reaction on Nitroethane........................105
Urethanes and Polyurethanes... ........................106
Summary and Conclusion ...............................109

REFERENCES........................................................ 110

BIOGRAPHICAL SKETCH.. ...........................................113















LIST OF TABLES


Table Page

1 Reaction of 2-nitropropane with NMPD and formaldehyde.......57

2 Reaction of (18) with DMPA............ ........ 58

3 Reaction of N-methylethanolamine and compound (18)..........59















LIST OF FIGURES


Figure Page

1 1H NMR spectrum of the model compound (21) in CDC13.......60

2 Completely decoupled 13C NMR spectrum of compound
(21) in CDC13............................................. 61

3 1H NMR spectrum of compound (13) in CDC13.................63

4 Completely decoupled 13C NMR spectrum of compound
(13) in CDC13.................. ....... .................... 64

5 1H NMR spectra (in CDC13) of the model compounds
utilizing 2-nitropropane as chain-stopping reagent........66

6 Plot of the number of repeating limits vs. reactant
feed ratio............... ...........................68

7 1H NMR spectrum of compound (30) in CDC13.................69

8 Completely decoupled 13C NMR spectrum of compound
(30) in CDC13............................................ 70

9 1H NMR spectrum of compound (24) in CDC13................72

10 Completely decoupled 13C NMR spectrum of the compound
(24) in CDC13............... ......... .............. .......... 73

11 13C NMR spectra of compound (26) in DMSO-d6:
(1) completely decoupled; (2) off-resonance..............75

12 Selected time dependent 1H NMR spectra of the reaction of
NHEP with compound (19) in DMSO-d6 at RT.................78

13 Plot of the consumption of NEPD vs. reaction time.........79

14 1H NMR spectra of compound (15) in DMSO-d6:
(1) without D20, (2) 1 drop of D20 was added..............82

15 13C NMR spectra of compound (15) in DMSO-d6:
(1) completely decoupled; (2) off-resonance...............83









16 1H NMR spectrum of compound (31) in CDC13...............85

17 13C NMR spectra of compound (31) in CDC13:
(1) completely decoupled; (2) off-resonance..............86

18 13C NMR spectra of compound (32) in CDC13:
(1) completely decoupled, (2) INEPT (CH, CH3 pos.,
CH2 neg., C, solvent suppressed)..........................87

19 13C NMR spectra of polymer (35) in CDC13:
(1) completely decoupled; (2) off-resonance...............89

20 13C NMR spectra of polymer (36) in CDC13:
(1) completely decoupled, (2) INEPT (CH, CH3 pos.,
CH2 neg., C, solvent suppressed).........................91

21 IR spectra of (1) compound (27), and (2) compound
(39) (reduced by NaBH4 and Pd/C).........................96

22 IR spectra of (1) compound (27), and (2) compound
(39) (reduced by H2/Raney Ni).............................97

23 13C NMR spectra of compound (39) in CDC13:
(1) completely decoupled; (2) off-resonance..............98

24 IR spectra of (1) polymer (35), and (2) polymer (40).....100

25 IR spectra of (1) polymer (36), and (2) polymer (41).....101

26 IR spectra of (1) polymer (37), and (2) polymer (42).....102

27 13C NMR spectra (INEPT: CH3, CH pos., CH2 neg.;
C, solvent suppressed) of compounds (40) and (43),
respectively...........................................104


viii















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

PREPARATION OF POLYMERS
VIA MANNICH REACTION

BY

SEOK HEUI HONG

May, 1985

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

In order to achieve the objective of this research, which was to

utilize the Mannich reaction to synthesize new water-soluble

polymers, several model compounds were studied. The reaction of N,N-

dimethyl-1,3-propanediamine with formaldehyde and 2-nitropropane was

carried out, and the best result was obtained utilizing the methylol

derivative of 2-nitropropane at a lower temperature with a base

catalyst. The reactions of other amines, i.e., N-methylethanolamine

and piperazine, with formaldehyde and 2-nitropropane were undertaken

with similar results. Some bis-secondary amines, i.e., N,N'-

dimethylethylenediamine (DMEA), N,N'-dimethyl-2-butene-1,4-diamine

(DMBA) and N,N'-dimethylhexamethylenediamine (DMHA), were also

studied. In an attempt to provide a better understanding of the

polymerization, model compounds with controlled molecular weights

were studied utilizing chain-stopper components.









Polymers of the desired structure were obtained from reactions

of the methylol derivative of nitroethane with bis-secondary amines,

including DMEA, DMBA, and DMHA. Alternatively, N,N,N',N'-

tetramethyl-2-methyl-2-nitro-1,3-propanediamine was reacted with

DMEA, DMBA and DMHA to yield polymers of the same structure. These

polymers containing nitro groups were reduced by hydrogen gas in the

presence of Raney nickel to afford the corresponding amine-containing

polymers. Upon treatment with formic acid and formaldehyde, the

polymers underwent methylation to afford the corresponding

polyamines. Since the polymers prepared were of relatively low

molecular weight, an attempt was made to prepare high molecular

weight polymers utilizing nitroethane. However, the Mannich reaction

of nitroethene with formaldehyde and dimethylamine yielded a dark

brown tar-like material which was not identifiable. The model

compound prepared from nitroethane, formaldehyde and N-(0-

hydroxyethyl)piperazine was reacted with methylenedi-p-phenylene-

diisocyanate to afford the corresponding polyurethane, which has the

intrinsic viscosity of 0.194 dl/g in DMSO at 300C. Similarly, the

same model compound was reacted with hexamethylenediisocyanate to

yield the corresponding polyurethane.














CHAPTER I
INTRODUCTION


The Mannich reaction is defined as the condensation of ammonia

or a primary or secondary amine with formaldehyde and a compound

containing at least one hydrogen atom of pronounced reactivity. The

first observation of this type was made by Tollens, who isolated the

tertiary amine from ammonium chloride, formaldehyde and

acetophenone.1,2 However, the detailed study of the reaction was

initiated in 1912 by Mannich who observed that antipyrine (1),

formaldehyde and ammonium chloride reacted to form a tertiary

amine.3 Thus, the reaction has become known generally as the


CH3
I3
N- CCH
/ 3
3 C6H5N K

C- CH
II
0

(1)


+ 3 HCHO + NH4C1


CH
1 3


CH2---N.HC1









Mannich reaction, and is recognized as one of the classical reactions

of organic chemistry. This reaction has been widely used in

synthesis and was the subject of many reviews.4-6

The mechanism of the Mannich reaction has been well

investigated, and a comprehensive review covering up to 1968 has been

published.7 Only a few of the main points will be discussed here.

The Mannich reaction leads to products of the type (6), bearing a

substituted methylene group connecting the substrate residue with



+ +H2
H2HC-N N HO-CH2-N(
(2a) (3)
I II
-R-H + I +H20 + HN--

+ =NH
2C=N< ( )N-CH2-N< ,
(2b) (4)
R-H + HCHO + HN-- ->RCH 2N

(6)

III IV
R-CH2OH + HN(

(5)

an amino group. The condensation reaction occurs in 2 steps. First,

the amine reacts with formaldehyde to give condensation product

2#3#4 (Step I), which then attacks the substrate R-H (Step II).

Even though this is believed to be the main route of the reaction,








some successful reactions between hydroxymethyl derivatives (5) and

alkylamines to give Mannich bases (6) are known.

The reactive species in acidic medium is the iminium ion (2),

derived principally from methylene-bis-amine (4) and secondarily from

hydroxymethylamine (3). In basic medium, the reactant is postulated

to be hydroxymethylamine (3) or, more probably, methylene-bis-amine

(4). The existence of cation (2) in aqueous solutions of amine and

formaldehyde has been demonstrated by polarographic methods; the

maximum concentration of (2) was reported to occur at pH 10-11.



The Use of Amines
The choice of the amine used in the reaction is important. It

is known that primary amines can react at both amine H-atoms, and

therefore it is difficult to obtain secondary Mannich bases free from

tertiary derivatives. However, use of the sterically hindered amine

(7), or similar amines containing bulky groups (t-butyl, di- or tri-

arylmethyl), can prevent a substitution reaction involving the second

amine H-atom of (7). The bulky alkyl groups can subsequently be

removed by hydrolysis to give the N-unsubstituted aminoketone (9),

which is not directly obtainable from ammonia and formaldehyde.8'9











(M- CCH3 + HA2---CH- 0CCH3 ---
(7)



0 0
CH3N formic acid NH
I HBr2
H OCH 3 A-
(8) (9)

It is also known that use of the oxalate derivatives of the primary
amines instead of the corresponding hydrochlorides makes the
synthesis of secondary Mannich bases in high yields possible.8,10
The use of secondary bifunctional amines such as piperazine
leads to symmetric Mannich bases, in which both of the amino groups
have reacted. Attempts to restrict the reaction to only one amine
function or hydrolysis of the Mannich products obtained from
piperazines invariably leads to the formation of disubstituted
piperazines (10).11


R-H + HCHO + HN NH --- RCH N N CH R
(10)

The Mannich reaction of bis-(2-chloroethyl)amine can give a
bicyclic salt as by-product.12 Two molecules of the amine thus
condense with one molecule of formaldehyde to give (11), which shows
cytostatic properties as do halogenated derivatives of similar
structure.13,14









C 1^ N C1
H
+ +^\+
HCHO C Cl' NI N -^\,, CI
+ I
H 2C1
C1 N N C C1
s--/ (11)



Nitroalkanes

Henry was the first to show that Mannich type reactions will

occur with nitroalkanes.15,16 He established that N-hydroxymethyl-

piperidine condensed with nitromethane and nitroethane to yield,

respectively, 2-nitro-1,3-dipiperidinopropane (12a) and 2-methyl-2-

nitro-1,3-dipiperidinopropane (12b).


R
2 Q NCH2OH + CH2RNO2 > 02N-C-(CH2ND )2

(12)
(12a), R = H
(12b), R = CH3


Later, Senkus successfully carried out reactions using methylamine,

isopropylamine, 1-butylamine, 2-butylamine, benzylamine, 1-

phenylethylamine, 2-amino-l-butanol, and 2-amino-2-inethyl-l-propanol

as monoalkylamine components; and nitroethane, 1- and 2-nitropropane,

and 2-nitrobutane as nitro components.17 He showed that the products

could be obtained either by allowing the amine to react with

formaldehyde and thereafter adding the nitroalkane, or by first








generating the methylol derivative of the nitroalkane, which was then

treated with the amine.


R R
I I
R'NHCH2OH + HC-NO2 -- > R'NHCH2CNO2 + H20
R R


R
2R'NHCH2OH + RCH2NO2 > R'NHCH2CCH2NHR' + H20
NO2

alternatively,

R R
I I
R'NH2 + HOCH2-C-N02 -- R'NHCH2CNO2 + H20
R R


R R
2R'NH2 + HOCH2-C-CH2OH ----> R'NHCH2C-CH2NHR' + H20
NO2 N02


Johnson extended the work of Senkus to various aliphatic

secondary amines.18 He also carried out these reactions by two

different methods: (A) reaction of the amines, formaldehyde and

nitroparaffin; and (B) reaction of the amine with the nitro alcohol

or nitro diol. Although the same end-products resulted in either

case, the latter reaction was slower. It is also shown that

unsubstituted piperazine and 3,5-dimethylpiperazine gave the

corresponding bis condensation products (13).19










CH CH CH
HN NH + 2 HCHO + 2 HC-N2 ---> H3C-C-CH-N N-CH2-CCH3
CH3 NO2 NO2


(13)




Polymeric Mannich Bases

Even though the Mannich reaction has been widely investigated

mechanically and used extensively in synthesis of small molecules, it

has been used only in a very limited manner in synthesis of

macromolecules. Apparently, the first application to synthesis of

macromolecules was by Bruson and Butler, who condensed 2,4,6-

trinitrotoluene with formaldehyde and ammonia to yield explosive

plastics.20 This was followed by Butler and Benjamin who condensed
phenols with formaldehyde and primary or secondary amines to

synthesize ion-exchange resins.21 Later, Tsuchida and Tomono

condensed pyrrole, formaldehyde and amines to yield polymers.22

Tomono, Hasegawa and Tsuchida extended the earlier work to include

other active hydrogen compounds as well.23 McDonald and Beaver later

published some of the details of modification of polyacrylamide by

use of the Mannich reaction.24 Recently, Andreani and coworkers

reported a synthetic route to tertiary amino polymers, namely the

polycondensation of bis(B-dialkylaminoketone)s, i.e. bis(Mannich

bases) with bis-secondary amines to yield poly(O-aminoketone)s.25










0 R
X (CH 3) N^N N(CH + X HN 'NH


0 R

>L ---i- U -J


Angeloni and co-workers extended this work to aromatic Mannich bases
such as 4,4 -bis(B-dimethylaminopropionyl)diphenyl or 4,4 -bis(B-
dimethylaminopropionyl)di-phenylether.26'27 Ghedini and coworkers
also extended this work to phenolic Mannich bases such as 2,6-bis(di-
methylaminomethyl)-4-methyl phenol .28


Proposal of Research
It is the objective of the research to utilize the Mannich
reaction between formaldehyde, selected amines and the nitroparaffins
as the active hydrogen compounds to synthesize amine-containing
and/or quaternary ammonium containing polymers. The reactions
anticipated to occur are as follows:











n RCH2NO2 + 2n HCHO + n R'NH2


F R
---- ---CH2-C-CH2-l-- + 2n H20
S NO2 n


~ R R
CH2-C-CH2-N

NH2



{ R R
Methylation I I
t t --CH 2-C-CH 2-N

N(CH3) n




Quaternization 1+
{--CH2 -C--CH2--N

+N(CH3)3 CH3 n


R = CH3 or C2H5


Nitroethane, as well as 1-nitropropane, can be utilized as the active

hydrogen compound. Both nitroparaffins should result in polymers of

high charge density. The resulting polymers from nitroethane and 1-

nitropropane would have an equivalent weight with respect to

quaternary ammonium centers (chloride form) of 114.5 and 121.5,

respectively.

It is well recognized that the effectiveness of cationic

polymers in the flocculation and coagulation applications is a direct









function of the charge density on the polymer. Thus, it would be

predicted that the quaternized polymer derived from polyethyleneamine

would be most effective having an eq. wt. of 107.5 (chloride form):



CH Cl



CH3 n


However, such a polymer has been shown to be relatively unstable due

to the proximity of the positive charges. An alternative polymer of

high charge density is poly(vinyltrimethylammonium chloride) of eq.

wt. of 121.5:


CH -CH

+N(CH3)3 n
S Cl


However, this polymer is difficult to synthesize and its cost would

be high. The most widely used cationic polymer in the flocculation

area of application is perhaps poly(diallyldimethylammonium chloride)

of eq. wt. 161.5:


-- CH2 -- o CH2 ----- CH2


H C'
3









Again, this polymer is made from a fairly expensive monomer and has

relatively high equivalent weight per charge.

Considerable versatility is envisioned in the above system. For

example, use of either 2-nitro-propane or a secondary amine would

produce polymers with molecular weight control, as both of these

reactants would function as chain-stoppers:



R R CH-
-CH2C--CH2--N CH2- C- N(CH33
1 1 1)3
+N(CH )3 CH3 n CH3


2-nitropropane as chain-stopper


R[ R 8'
1+ I +
-CH N --CH- --C CH ---N-CH
2 2 2 1 3
CH +N(CH93 n R


Secondary amine as chain-stopper


Use of nitromethane or ammonia would result in crosslinked

polymers. Thus, it is apparent that a wide variety of products are

possible from the proposed reactions.

The problem anticipated is the known requirement of considerably

high molecular weights for effective flocculation and coagulation

characteristics in cationic polymers. The reaction proposed, the

Mannich reaction, for polymer synthesis can be classified as an

example of condensation polymerization or step-growth polymeriza-

tion. And such processes are known to require (A) relatively pure





12


reactants; and (B) rigidly controlled stoichiometry in order to

attain high molecular weights. Thus one of the major objectives of

the research is to attain the necessary stoichiometric control to

lead to the desired degrees of polymerization.














CHAPTER II
EXPERIMENTAL



General

Melting points, given in degrees Celsius, were determined on a

Thomas-Hoover Capillary Melting Point Apparatus and are reported

uncorrected. Pressures are expressed in millimeters of mercury (mm

Hg). Elemental analyses were performed by either Atlantic Microlabs,

Inc., Atlanta, Georgia, or Department of Chemistry, University of

Florida, Gainesville, Florida.

Proton nuclear magnetic resonance (NMR) spectra (60 MHz) were

recorded on a Varian EM360L instrument. Carbon-13 NMR (25 MHz) and

100 MHz proton NMR spectra were recorded on a Jeol-JNM-FX-100

spectrometer. Chemical shifts are expressed in parts per million

(ppm) on the 6 scale downfield from tetramethylsilane (TMS) or sodium

2,2-dimethyl-2-silapentane-5-sulfonate (DSS) unless otherwise

indicated. In cases where no internal reference was added, spectra

were calibrated via a characteristic signal of the deuterated solvent

used.29 The solvent used and calibration information are given in

parentheses for each spectrum reported. Multiplicities of proton and

off-resonance decoupled carbon resonances are designated as singlet

(s), doublet (d), triplet (t), quartet (q) or multiple (m).









Infrared (IR) spectra were recorded on a Perkin-Elmer 281

spectrophotometer. Absorbances are expressed in wavenumbers (cm-1)

using the 1601 cm-1 line of standard. Solid samples were run as a

KBr pellet; liquid samples were analyzed neat as a thin film between

NaCl plates. Absorption bands are assigned the classifications weak

(w), medium (m), strong (s), broad (br) and shoulder (sh).

Molecular weights of polymers were determined by vapor pressure

osmometry (VPO) on a WESCAN model 233 Molecular Weight Apparatus.

Benzil was used as a calibration standard. intrinsic viscosities

were measured with Ubbelohde viscometer (dilution viscometer).



Reagents and Solvents

Reagents were obtained from Aldrich Chemical Co., Eastman Kodak

Co., Fischer Scientific Co. or Mallinckrodt, Inc., unless otherwise

noted. Deutrated solvents were purchased from Merck & Co., Inc., and

Aldrich Co.

All solvents used for general applications were of Reagent grade

or ACS grade quality. For special applications, solvents were

purified as needed by following procedures reported in the

literature.30 Thus, dimethylsulfoxide (DMSO) and N,N-dimethyl-

formamide (DMF) were allowed to stand over potassium hydroxide

pellets and distilled from calcium oxide under reduced pressure;

ethanol-free chloroform (CHC13) was obtained by extraction of reagent

grade CHC13 with concentrated H2S04 and water, followed by

distillation from phosphorus pentoxide (P4010).









Synthesis of Nitroalcohols

2-Nitroethanol (14)

The procedure reported by Burmistrou and Bashinova31 was

modified as follows. Nitromethane (610 g, 10 moles) and para-

formaldehyde (30.0 g, 1 mole) were placed into a 2,000 ml three-

necked round-bottomed flask fitted with a thermometer and a reflux

condenser. The mixture was heated in an oil bath to 105-110"C and

potassium carbonate (0.64 g, 0.1% of the reaction mixture) was added

in 10 portions. Each successive portion of catalyst (K2CO3) was

added after vigorous boiling of the mixture ceased. During the

additions, the color (cloudiness) of the mixture disappeared

slowly. When the paraformaldehyde was completely dissolved to yield

a clear solution, the mixture was held for 30 minutes at the same

temperature, cooled, filtered to separate the catalyst, and

neutralized with 4 drops of concentrated H2S04. The light yellow

filtrate was distilled under reduced pressure to remove excess

nitromethane (30-34*C at 30-60 mm Hg, then held at 5-7 mm Hg for 30

min.). The yellow residue was transferred to a 100 ml. round-

bottomed flask and distilled under vacuum (59-63*C at .25 mm Hg) to

yield 52 g (57.1%) of crystal clear liquid, no4 1.4434 [literature

value 1.4438].32

1H (CDC13,TMS): 6 4.14 (m,2H), 4.54 (m,2H).

2-Nitro-1,3-propanediol (15)

Procedure A: The following procedure was modified from the

procedure of Den Otter.33 Paraformaldehyde (38 g, 1.265 mole),

nitromethane (22.5 g, 0.369 mole) and 10 drops of 33% aqueous









potassium hydroxide were heated with 350 ml of methanol under reflux

in an oil bath. The 2-(hydroxymethyl)-2-nitrol-1,3-propanedio1 (16),

formed during the reaction, was not isolated, but used in the

dissolved condition. A solution of sodium (10.5 g, 0.457 mole) in

150 ml of methanol was added dropwise to the solution, which was

stirred and cooled in an ice bath. During this addition, a

precipitate of the sodium derivative of 2-nitro-1,3-propanediol (17)

began to separate and this separation was complete after the flask

had stood overnight in a refrigerator. The filtered and dried sodium

derivative of 2-nitro-1,3-propanediol (60 g) was mixed in 300 ml of

ether and added in 5 equal portions to a solution of 40 g of

salicylic acid in 250 ml of ether, which was brought to reflux.

After 3 hours of reflux, the mixture was cooled, the sodium

salicylate filtered off and the ether evaporated. The resulting oil

was added to a hot mixture of 1:1.7 ethylacetate and chloroform to

yield a clear yellow solution, which was placed in a refrigerator

overnight to yield white crystals. The filtered crystals were

recrystallized from a 1:1.7 ethylacetate and chloroform mixture to

yield needle-like white crystals (33 g, 73.9% yield), m.p. 53*C

[literature m.p. 54C].33

Sodium derivative of 2-nitro-1,3-propanediol (17)

1H (D20,DSS): 6 4.37 (S,2H), 3.31 (S,4H).

2-nitro-1,3-propanediol (15)

1H (DMSO-d6,TMS): 6 3.72 (m,4H), 4.66 (m,1H), 5.27 (t,2H).

13C (DMSO-d6, 39.5): 6 59.555, 91.917.








IR (KBr): 3380 (s,br), 2950 (m), 2900 (m), 1550 (s), 1460 (s),

1360 (s,sh), 1330 (s), 1245 (m), 1210 (m), 1075 (s,sh), 1010 (s), 975

(w), 915 (w,sh), 865 (m), 770 (w) cm-1.

Analysis, calculated for C3H7N04: C, 29.75; H, 5.83; N, 11.57.

Found: C, 29.83; H, 5.84; N, 11.55.

Procedure B: A mixture of nitromethane (12.108 g, 0.2 mole) and

calcium hydroxide (0.065 g) was placed in a 250 ml round-bottomed

flask equipped with a stirrer and a condenser, and cooled in an

external ice bath. After cooling, 32.465 g of formalin solution (37%

w/w aqueous, 0.4 mole) was added slowly from a dropping funnel.

After the addition was complete, the solution was stirred at room

temperature for 66 hours. Carbon dioxide in the form of dry-ice was

added in excess and the calcium carbonate was filtered. The filtrate

was evaporated at 90*C under reduced pressure to yield a molten, dark

brown, viscous oil, which upon cooling, solidified. The resulting

solid was recrystallized from a 1:1.7 ethylacetate-chloroform mixture

to yield a white crystalline product (18.3 g, 60.6%) which turned out

to be 2-(hydroxymethyl)-2-nitro-1,3-propanediol (16).

1H (acetone-d6,TMS): 6 4.05 (d,6H), 4.33 (t,3H).

2-Methyl-2-nitro-l-propanol (18)

The following procedure was modified from the procedure of

Vandervilt and Hass.34 To a 500 ml three-necked round-bottomed flask

equipped with a mechanical stirrer and thermometer was added 44.5 g

(0.499 mole) of freshly distilled 2-nitropropane and 0.125 g of

calcium hydroxide. The mixture was cooled in an external ice bath to

0-5*C, after which 41 g (0.505 mole) of formalin solution (37% w/w









aqueous) was added dropwise from the dropping funnel. After the

addition was complete, the solution was stirred at room temperature

for 43 hours. Carbon dioxide in the form of dry-ice was added in

excess and the calcium carbonate precipitate was removed by

filtration. The precipitate was washed with 10 ml of water, and the

combined filtrate and washings were evaporated at 90*C under reduced

pressure. The remaining molten product, which solidified upon

cooling, was recrystallized from 1:10 butanol-benzene to yield 54.5 g

(91.5%) of white crystalline product, m.p. 88-89*C [literature m.p.

89.5-90"C].34

1H NMR (CDC13,TMS): 6 1.58 (s,6H), 2.86 (s,1H), 3.84 (s,2H).

1C NMR (CDC13,77.0): 6 22.73, 68.13, 88.72.

IR (KBr): 3440 (s,br), 3000 (m), 2940 (m), 2880 (m), 1545 (s),

1465 (m), 1410 (w), 1400 (w), 1375 (m), 1350 (m,sh), 1150 (w), 1067

(m,sh), 990 (w), 860 (w,sh), 820 (w), 730 (w) cm-1.

2-Methyl-2-nitro-1,3-propanediol (19)

By use of the same procedure as reported for the previous

compound on preparation of this compound was accomplished by adding

slowly 160 g (2 mole) of formalin solution (37% w/w aqueous) to a

mixture of 75 g (1 mole) of nitroethane and 0.25 g of calcium

hydroxide. After stirring for 43 hours at room temperature, and a

slight excess of carbon dioxide had been added, the white precipitate

which formed was filtered and washed. The filtrate and washings were

combined and evaporated at 90"C under reduced pressure to yield

molten product, which upon cooling, solidified. The crude product

was recrystallized from 1:10 butanol-benzene to yield 113 g (83.7%)








of white crystalline product, m.p. 153-1550C [literature m.p. 149-

1500C].34

1H NMR (CDC13,TMS): 6 1.52 (s,3H), 2.46 (t,2H), 4.07 (d,4H).

13C NMR (CDC13, 77.0): 6 16.93, 64.02, 93.11.

IR (KBr): 3300 (s,br), 3000 (m), 2960 (m), 2890 (m), 2100 (w),

1540 (s), 1470 (m), 1440 (m), 1410 (m), 1370 (m), 1360 (m,sh), 1305

(m), 1240 (m), 1215 (w), 1180 (m), 1130 (m), 1080 (m), 1035 (s), 985

(m), 950 (m), 905 (m), 870 (m), 835 (m), 745 (m), 740 (m,sh), 675

(m,br) cm-1.

2-Ethyl-2-nitro-1,3-propanediol (20)

Preparation of this compound was achieved as previously

described by adding 160 g (2 mole) formalin solution (37% w/w

aqueous) to a mixture of 89 g (1 mole) of 1-nitro-propane and 0.25 g

of calcium hydroxide. The recrystallization yielded white

crystalline product (126 g, 84.5%), m.p. 55-56.5*C [literature m.p.

56-C].34

1H NMR (CDC13,TMS): 6 0.90 (t,3H), 1.90 (q,2H), 3.04 (s,2H),

4.11 (m,4H).

13C NMR (CDC13,77.0): 6 7.650, 25.777, 63.743, 94.253.

IR (KBr): 3400 (s,br), 2980 (m), 2890 (m), 1540 (s), 1425 (m),

1360 (m), 1310 (w), 1250 (w,sh), 1190 (w), 1065 (s,sh), 975 (m), 905

(w), 860 (m), 815 (m), 785 (m), 720 (w), 640 (w) cm-1.








Synthesis of Model Compounds

N-(2-Hydroxyethy1)-N-methy1-(2-methyl-2-nitro-l-propy1)
amine (21)

Procedure A: In a 100 ml round-bottomed flask were placed 5.955

g (0.0500 mole) of 2-methyl-2-nitro-l-propanol (18) in 20 ml of

freshly distilled THF and 4 A molecular sieves, and 3.756 g (0.0500

mole) of N-methylethanolamine in 10 ml of THF was added slowly by

means of a dropping funnel. After the addition was complete, the

reaction was stirred for 72 hours, with fresh molecular sieves (4 A)

added every 12 hours. The molecular sieves were filtered, and the

solvent was evaporated under reduced pressure to yield a yellow oil,

4.88 g (55.4%).

Procedure B: The same procedure was used with the exception of

addition of triethylamine (1 ml) to the reaction mixture. Thus, the

reaction of (18) (5.957 g, 0.05 mole) and N-methyl-ethanolamine

(3.757 g, 0.05 mole) afforded yellow oil (5.86 g, 66.5%).

Procedure C: The reaction mixture (alcohol, amine and catalyst

NEt3) in THF was stirred and refluxed for 20 hours and cooled to room

temperature. The solvent was removed by evaporation under reduced

pressure to yield a yellow oil (5.95 g, 76.5%).

Analysis, calculated for C7H16N203; C, 47.71; H, 9.15; N, 15.90.

Found: C, 47.72; H, 9.11; N, 15.78.

1H NMR (CDC13,TMS): 6 1.57 (s,6H), 2.27 (s,3H), 2.54 (s,lH),

2.62 (t,2H), 2.88 (s,2H), 3.53 (t,2H).

13C NMR (CDC13,77.0): 6 23.24, 43.13, 58.63, 60.77, 66.18,


88.26.









IR (KBr): 3400 (s,br), 2980 (s), 2945 (s), 2870 (s), 2800 (m),

1770 (w), 1640 (w), 1530 (s), 1455 (s), 1400 (s), 1370 (s), 1345

(s,sh), 1280 (w), 1220 (w), 1185 (w), 1160 (w), 1120 (m), 1065 (s),

1035 (s,sh), 980 (w), 945 (w), 900 (w), 855 (m,sh), 815 (w), 790 (w)

cm-1.

2-Ethyl-2-nitro-1,3-bis(2-hydroxyethyl-N-methy1)amino
propane (22)

The solution of 3.756 g (0.0500 mole) of N-methylethanolamine

and 3.729 g (0.025 mole) of 2-ethyl-2-nitro-1,3-propanediol (21) with

4 A molecular sieves in 70 ml THF was stirred for 60 hours at room

temperature. The molecular sieves were filtered out and the filtrate

was evaporated under reduced pressure to yield a yellow oil (4.76 g,

72.4%).

1H NMR (CDC13,TMS): 6 0.94 (t,3H), 1.89 (q,2H), 2.30 (s,3H),

2.42 (s,3H), 2.91 (t,4H), 3.23 (s,4H), 3.57 (t,4H), 4.21 (s,2H).

N,N-Dimethyl-N',N'-bis(2-methyl-2-nitro-1-propy1)-1,3-
propanediamine (23)

Procedure A: To a solution of N,N-dimethyl-1,3-propanediamine

(DMPA) (5.109 g, 0.050 mole) in 20 ml of 1,4-dioxane was added

formalin solution (8.303 g, 37% w/w aqueous, 0.100 mole). A

catalytic amount (-0.1 g) of hydrochloric acid was added and

stirred. To this mixture, 2-nitropropane (9.091 g, 0.102 mole) was

added and stirring was continued for 50 hours at 600C. The reaction

mixture was cooled, neutralized with 1 g of NaOH and extracted with

3x30 ml of methylene chloride. The combined organic phase was dried

over MgSO4 overnight, filtered and evaporated to yield a yellow oil

(7.55 g, 49.7%).









Procedure B: To a solution of 2-nitropropane (4.546 g, 0.051

mole) in 20 ml of 1,4-dioxane at 0-50C (in an external ice bath) was

added formalin solution (4.015 g, 37% w/w aqueous, 0.0495 mole) and

potassium carbonate (0.235 g). The ice bath was removed and the

mixture was stirred at room temperature for 45 hours. Then N,N-

dimethyl-1,3-propanediamine (2.555 g, 0.025 mole) in 10 ml of

1,4-dioxane was added. The reaction mixture was brought to reflux

and extracted with 3x40 ml of ether. The combined organic phase was

dried over MgSO4 overnight, filtered and evaporated to yield yellow

oil (1.87 g, 24.6%).

Procedure C: To an ice-cooled 250 ml round-bottomed flask

containing 2-nitro-2-methyl-propano1 (11.91 g, 0.1 mole) in 25 ml of

*water was slowly added N,N-dimethyl-1,3-propanediamine (5.109 g,

0.050 mole) in 20 ml of 1,4-dioxane. After the addition was

complete, the solution was stirred at 0-5*C for 1 hour, then at 60-

70%C for 18 hours. This was extracted with 3x30 ml of methylene

chloride, and the combined organic phase was dried over MgSO4,

filtered and evaporated to yield a yellow oil (7.73 g, 50.9% yield).

Analysis, calculated for C13H28N404: C, 51.31; H, 9.21; N,

18.42. Found: C, 51.18; H, 9.13; N, 18.52.

1H NMR (CDC13,TMS): 6 1.55 (s,12H), 2.15 (m,2H), 2.19 (s,6H),

2.6 (m,4H), 3.08 (m,4H).

13C NMR (CDC13,77.0): 6 22.41, 24.22, 45.08, 52.68, 57.02,

63.89, 88.45.

IR (Neat): 3350 (m,br), 2995 (s), 2950 (s), 2870 (s), 2830 (s),

2790 (s), 1540 (s), 1470 (s), 1400 (m), 1375 (s), 1350 (s), 1285









(m,br), 1200 (w), 1160 (m,sh), 1080 (m), 1040 (m), 1025 (m), 990 (w),

950 (w), 910 (w), 860 (s), 820 (m,sh), 750 (w,br), 650 (w) cm-1.

N,N'-Bis(2-methyl-2-nitro-l-propyl)piperazine (13)

In a 100 ml 3-necked round-bottomed flask equipped with a

dropping funnel charged with 1,4-dioxane, a stirrer and a Dean-Stark

trap were placed 2-nitropropane (1.72 g, 0.02 mole), formalin

solution (1.62 g, 37% w/w aqueous, 0.02 mole) and piperazine (0.86 g,

0.01 mole) in 20 ml of 1,4-dioxane. A catalytic amount (~0.5 ml) of

sodium hydroxide solution (10% w/v, aqueous) was added and the

reaction mixture was brought to reflux. The solvent was added from

the dropping funnel to keep the volume constant. When the boiling

point of the azeotropic mixture reached 1000C, addition of solvent

was stopped and the volume of the reaction mixture was reduced to

~1/2 of the original volume. Petroleum ether was added to this

reaction mixture and the upper layer was decanted. The resulting oil

was crystallized from acetone to yield a yellowish white powder (1.98

g, 71.2% yield).

Analysis, calculated for C12H14N404: C, 50.00; H, 8.33; N,

19.44. Found: C, 49.78; H, 8.90; N, 19.32.

1H NMR (CDC13,TMS): 6 1.54 (s,12H), 2.47 (s,8H), 2.83 (s,4H).

13C NMR (CDC13,77.0): 6 24.072, 55.117, 65.669, 88.648.

IR (KBr): 2940 (m,sh), 2860 (w,sh), 2800 (m,sh), 2740 (w,sh),

1700 (w), 1560 (s), 1455 (m), 1400 (m), 1370 (m,sh), 1340 (s), 1320

(s), 1285 (w), 1235 (w), 1190 (w), 1155 (s), 1115 (m), 1015 (m), 990

(w), 945 (w,sh), 890 (w), 855 (h), 830 (m,sh), 640 (w) cm-1.









2-Methyl-2-nitro-1,3-bisN'-(8-hydroxy-ethyl )-N-
piperazino propane (24)

Procedure A: To a formalin solution (3.28 g, 0.0404 mole) were

added nitroethane (1.501 g, 0.0200 mole) and N-(8-hydroxyethyl)-

piperazine (5.208 g, 0.0400 mole). Sodium hydroxide solution (5% w/v

aqueous, 1 ml) was added to this mixture. Upon addition, an

exothermic reaction occurred immediately and a white precipitate

formed, which was not soluble in 1,4-dioxane. Petroleum ether was

added to this mixture, and the solid was filtered and dried to yield

white crystals (5.34 g, 74.4% yield) which were recrystallized in

acetone, m.p. 118-1200C.

Procedure B: In a 100 ml round-bottomed flask was placed a

solution of N-(8-hydroxyethyl)piperazine (5.209 g, 0.04 mole) in 20

ml of 1,4-dioxane with sodium hydroxide solution (5% w/v aqueous, 1

ml). To this solution was slowly added a mixture of formalin

solution (37% w/w aqueous, 3.28 g, 0.04 mole) and nitroethane (1.502

g, 0.02 mole) in 10 ml of 1,4-dioxane. This reaction mixture was

brought to reflux for 2 hours, then the solvent was distilled until

the volume of the remainder became ~25 ml. Upon cooling, a yellowish

white precipitate formed after which petroleum ether (~50 ml) was

added with stirring; the precipitate which formed was filtered and

dried under reduced pressure to yield 5.94 g (82.7% yield) of

yellowish white crystals. Recrystallization from acetone gave white

crystals of mp 118-120'C.

Analysis, calculated for C16H33N504: C, 53.46; H, 9.25; N,

19.48. Found: C, 52.96; H, 9.34; N, 19.01.









1H NMR (CDC13,TMS): 6 1.59 (s,3H), 2.51 (s,20H), 2.78 (d of

d,4H), 3.59 (t,4H).

13C NMR (COC13,77.0): 6 19.32, 53.00, 55.02, 57.68, 59.11,

63.45, 92.52.

IR (Kbr): 3320 (s,Br), 2950 (s,sh), 2910 (m), 2905 (m), 2885

(m), 2805 (s,sh), 2700 (m), 1530 (s), 1460 (m), 1420 (w), 1400 (m),

1380 (m), 1360 (m), 1340 (m), 1330 (s,sh), 1280 (m), 1225 (w), 1160

(s), 1120 (m), 1100 (m,sh), 1060 (m,sh), 1050 (m), 1040 (m), 1010

(s), 990 (w), 965 (w), 930 (w), 920 (w), 870 (w), 860 (m), 840 (w),

830 (w,sh), 770 (w,sh) cm-1.

2-Ethyl-2-nitro-1,3-bis{N'-(B-hydroxyethy1)-N-
piperazinyllpropane (25)

This material was prepared by the methods reported for compound

(24).

Procedure A: To a solution of N-(8-hydroxyethyl)piperazine

(5.208 g, 0.04 mole) in 20 ml of 1,4-dioxane was added a mixture for

formalin solution (37% w/w aqueous, 3.28 g, 0.04 mole) and 1-

nitropropane (1.782 g, 0.02 mole) in 10 ml of 1,4-dioxane. Sodium

hydroxide solution (5% w/v aqueous, 1 ml) was added and the mixture

was refluxed for 2 hours. The azeotropic mixture of 1,4-dioxane and

H20 was distilled until the volume of the remaining solution became

25 ml. The resulting dark brown oil was crystallized from acetone to

yield a white flaky solid (3.9 g, 69.9% yield) which turned out to be

methylenebis[N'-(8-hydroxyethyl)]-N-piperazine (26). The filtrate

was evaporated to yield a brown oil (1.03 g, 13.8% yield) which was

crystallized from acetone. The yellowish white crystals obtained

were the desired product, m.p. 98-101"C.








Procedure B: A solution of N-(O-hydroxyethyl)piperazine (5.226

g, 0.0041 mole) in 10 ml of THF was slowly added to a solution of 2-

ethyl-2-nitro-1,3-propanediol (2.984 g, 0.02 mole) with NEt3 (0.82 g)

in 10 ml of THF. The reaction mixture was refluxed for 23 hrs and

cooled to room temperature. The solvent was removed under reduced

pressure to yield a yellow oil which was dried over molecular sieves

(4 A) for 20 hours at -~0C. During this time, white crystals formed

which were filtered and dried (2.611 g, 35.2% yield).

1H NMR (CDC13,TMS): 6 0.86 (t,3H), 2.02 (q,2H), 2.49 (s,20H),

2.87 (s,4H), 3.60 (t,4H).

13C NMR (DMSO-d6,39.5): 6 7.97, 24.19, 51.05, 53.17, 54.24,

58.39, 60.14, 94.87.

IR (KBr): 3300 (s,br), 2960 (s), 2940 (s), 2880 (s), 2820

(s,sh), 1700 (w), 1530 (s), 1460 (s), 1445 (m), 1420 (w), 1390 (m),

1365 (m), 1345 (s), 1330 (s), 1305 (s,sh), 1280 (m,sh), 1230 (w),

1205 (w), 1190 (w), 1160 (s), 1140 (m), 1120 (m,sh), 1090 (m,sh),

1050 (m), 1040 (s), 1005 (s), 990 (w), 930 (m,sh), 890 (w), 880 (w),

860 (m), 830 (m), 810 (w), 770 (m), 720 (w), 700 (w,br), 660 (w), 630

(w) cm-1.

Methylene-bis{N'-(8-hydroxyethyl)-N-piperazine} (26)

A formalin solution (37% aqueous, 0.8116 g, 0.01 mole) was added

to a solution of N-(a-hydroxyethyl)piperazine (2.604 g, 0.02 mole) in

10 ml of 1,4-dioxane. A sodium hydroxide solution (10% w/v aqueous,

2 ml) was added to this mixture followed by an additional 10 ml of

1,4-dioxane. This reaction mixture was refluxed for 3 hours, then

cooled to room temperature. Petroleum ether was added and the upper








layer was decanted. The resulting yellow oil was crystallized from

cold acetone to yield white flaky crystals (2.4 g, 88.2% yield), m.p.

134-135.5*C.

Analysis, calculated for C13H28N402: C, 57.32; H, 10.36; N,

20.57.

Found: C, 57.06; H, 10.33; N, 20.48.

1H (CDC13,TMS): 6 2.52 (s,20H), 2.93 (s,2H), 3.63 (t,4H).

13C (CDC13,77.0): 6 51.32, 52.88, 57.75, 59.50, 80.70.

IR (KBr): 3300 (s,Br), 2960 (s), 2940 (s), 2820 (s,sh), 1580

(w), 1510 (w), 1460 (m,sh), 1420 (m), 1370 (in), 1350 (s), 1320

(m,sh), 1290 (m,sh), 1270 (m), 1190 (m), 1170 (s,sh), 1140 (m), 1080

(m), 1060 (m), 1010 (m,sh), 930 (m,sh), 880 (w), 815 (m,sh), 770 (w)

cm-1.

2-Methyl-2-nitro-1,3-dipiperidinopropane (12b)

In a 500 ml round-bottomed flask equipped with a condenser was

placed a solution of 2-methyl-2-nitro-1,3-propanediol (40.439 g,

0.299 mole) in 250 ml of THF. A solution of piperidine (50.980 g,

0.599 mole) in 50 ml of THF was added, and the mixture was stirred

for 36 hours at room temperature, followed by evaporation of the

solvent. The resulting light yellow, viscous oil was crystallized in

cold methanol to yield white crystals (68.7 g, 85.3% yield).

Analysis, calculated for C14H27N302: C, 62.42; H, 10.10; N,

15.60. Found: C, 62.48; H, 10.13; N, 15.60.

1H NMR (CDC13,TMS): 6 1.43 (m,12H), 1.57 (s,3H), 2.40 (m,8H),

2.73 (m,4H).









13C NMR (COC13,77.0): 6 18.96, 23.88, 26.24, 56.53, 64.47,

93.06.

IR (KBr): 2930 (s), 2840 (m), 2780 (m,sh), 2340 (w), 1540 (s),

1440 (m,sh), 1380 (w), 1330 (m), 1295 (w), 1270 (w), 1150 (m), 1100

(m), 1090 (m), 1045 (m,sh), 1035 (m), 995 (m), 940 (w), 850 (m,sh),

880 (w), 790 (w), 775 (w) cm1.

2-Methyl-2-nitro-1,3-bis(dimethylamino)propane (27)

The following procedure was adopted from Johnson.18 In a 500 ml

Erlenmeyer flask was placed a mixture of 2-methyl-2-nitro-1,3-

propanediol (19) (67.56 g, 0.5 mole) and dimethylamine (40% aqueous,

112.73 g, 1 mole) and left in the refrigerator for 20 hours. A

reaction took place and phase separation occurred, the top layer

being solid. Ethyl ether (200 ml) was added and the aqueous phase

was separated, and washed with 50 ml of ether. The combined ether

layer was dried over K2CO3, filtered and evaporated to yield a yellow

liquid (81.6 g, 86.2% yield) which later solidified, m.p. 30-31"C

[literature m.p. 32*C].

1H NMR (COC13,TMS): 6 1.61 (s,3H), 2.22 (s,12H), 2.74 (m,4H).

13C (CDC13,77.0): 6 18.91, 47.49, 65.33, 92.53.

IR (Neat): 2940 (s), 2860 (m), 2795 (s,sh), 1525 (s,sh), 1450

(s), 1390 (w), 1370 (m), 1325 (s,sh), 1280 (m), 1150 (s,sh), 1090

(m), 1040 (m,sh), 1005 (s), 920 (w,sh), 850 (m), 810 (w), 790 (w),

650 (w) cm-1.

2-Ethyl-2-nitro-N,N'-bis(2-methyl-2-propano-
1-propyl)amine (28)
This material was prepared as described earlier for the case of

(27) by allowing 2-ethyl-2-nitro-1,3-propanediol (20) (74.58 g, 0.05









mole) and dimethylamine (40% w/w aqueous, 112.74 g, 1 mole) to react

overnight in a refrigerator. A reaction took place and a non-aqueous

phase separated. The aqueous phase was extracted with 3x30 ml of

ethyl ether and the combined organic phase was dried over K2CO3,

filtered and evaporated to yield a greenish yellow oil (83.4 g, 82.2%

yield). An attempt at further purification by vacuum distillation

failed due to the decomposition of the compound.

1H NMR (CDC13,TMS): 6 0.89 (t,3H), 2.07 (q,2H), 2.21 (s,12H),

2.74 (s,4H).

13C NMR (CDC13,77.0): 6 8.11, 24.43, 47.19, 61.29, 95.05.

IR (Neat): 2980 (m), 2950 (m), 2860 (m,sh), 2825 (m), 2780 (s),

1535 (s), 1460 (s,sh), 1385 (w), 1340 (m,sh), 1270 (w), 1150 (w),

1100 (w), 1040 (m,sh), 870 (w), 850 (w), 835 (w), 795 (w) cm-1.

N,N'-Dimethyl-N,N'-bis(2-methyl-2-nitro-1-propyl)-
ethylenediamine (29)

In a 100 ml round-bottomed flask equipped with a condenser was

placed a solution of N,N'-dimethylethylenediamine (3.717 g, 0.0422

mole), 2-nitropropane (7.521 g, 0.0844 mole) and formalin solution

(37% w/w aqueous, 6.845 g, 0.0844 mole) in 50 ml of 1,4-dioxane. A

catalytic amount of potassium hydroxide (33% aqueous, 1 ml) was

added, and the reaction mixture was heated to reflux for 2 hours.

The solvent (azeotropic mixture of 1,4-dioxane and water) was

distilled with constant addition of fresh 1,4-dioxane until the

boiling point of the azeotropic mixture reached 100*C. The resulting

viscous, yellow liquid crystallized upon cooling. This crude product

was dissolved in 125 ml of ethyl ether, washed with 3x30 ml of water,









dried over K2CO3 overnight, filtered and evaporated to yield white

crystals (6.8 g, 55.6% yield), m.p. 63-64.5*C.

Analysis calculated for C12H26N404: C, 49.63; H, 9.03; N,

19.30. Found: C, 49.67; H, 9.04; N, 19.22.

1H NMR (CDC13,TMS): 6 1.55 (s,12H), 2.28 (s,6H), 2.47 (s,4H),

2.84 (s,4H).

13C NMR (CDC13,77.0): 6 23.88, 44.36, 57.93, 67.08, 88.91.

IR (KBr): 2980 (s,sh), 2860 (m), 2820 (s,sh), 1530 (s), 1470

(m), 1455 (m), 1435 (m), 1400 (m), 1375 (m,sh), 1340 (s,sh), 1260

(m), 1240 (w), 1200 (m,sh), 1160 (w), 1100 (m,sh), 1040 (s), 1020

(m), 730 (w), 980 (w), 945 (w), 860 (m), 850 (m), 820 (w,sh) cm-1.

N,N'-Dimethyl-N,N'-bis(2-methyl-2-nitro-l-propyl)-2-
butene-1,4-diamine (30)

In a 250 ml round-bottomed flask equipped with a condenser was

placed a solution of N,N'-dimethyl-2-butene-1,4-diamine (3.342 g,

0.0293 mole) in 100 ml of 1,4-dioxane. Formalin solution (37% w/w

aqueous, 5.227 g, 0.0644 mole), 2-nitropropane (5.655 g, 0.0635 mole)

and potassium hydroxide (33% w/w aqueous, 3 ml) were added and the

reaction mixture was brought to reflux for 2 hours followed by

distillation of the azeotropic mixture of 1,4-dioxane and water with

constant addition of fresh dioxane. When the temperature of the

outcoming vapor reached 100'C, the addition of dioxane was stopped,

and the distillation was stopped when the residual reaction mixture

became cloudy. Ethyl ether (150 ml) was added, the solid portion was

filtered, and the filtrate was evaporated to yield a viscous yellow

oil (7.88 g, 85.1% yield). Storage overnight in a refrigerator









resulted in a yellow-white solid which was recrystallized from

methanol to yield white crystals, m.p. 62-63*C.

Analysis, calculated for C14H28N404: C, 53.14; H, 8.92; N,

17.71. Found: C, 53.23; H, 8.95; N, 17.68.

1H NMR (CDC13,TMS): 6 1.55 (s,12H), 2.25 (s,6H), 2.85 (s,4H),

3.03 (m,4H), 5.52 (m,2H).

13C NMR (CDC13,77.0): 6 24.20, 44.15, 61.35, 65.33, 88.85,

130.41.

IR (KBr): 2980 (s,sh), 2960 (m), 2920 (m,sh), 2860 (m,sh), 2940

(m), 2780 (s,sh), 1530 (s,sh), 1450 (s,sh), 1410 (w), 1395 (m), 1380

(m), 1370 (s), 1340 (s,sh), 1310 (m), 1255 (w,sh), 1210 (w), 1195

(w), 1165 (w), 1120 (m,sh), 1080 (w), 1040 (s), 1015 (w), 985 (s),

975 (m), 970 (m), 910 (w), 855 (s), 815 (w), 730 (w), 670 (w) cm-1.

N,N'-Dimethyl-N,N'-bis(2-methyl-2-nitro-l-propy1)-
hexamethylenediamine (31)

This compound was prepared by the procedure previously described

for the case of (30). N,N'-Dimethyl-hexamethylenediamine (1.561 g,

0.0108 mole), formalin solution (37% aqueous, 1.926 g, 0.0237 mole)

and 2-nitropropane (1.939 g, 0.0218 mole) were allowed to react in

the presence of potassium hydroxide (33% aqueous, 1 ml) to afford

yellow oil (2.14 g, 57.2% yield).

Analysis, calculated for C16H34N404: C, 55.46; H, 9.89; N,

16.17. Found: C, 55.52; H, 9.91; N, 16.23.

1H NMR (CDC13,TMS): 6 1.30 (s,8H), 1.58 (s,12H), 2.26 (s,6H),

2.42 (m,4H), 2.83 (s,4H).

13C NMR (CDC13,77.0): 6 23.97, 26.78, 27.33, 43.74, 59.70,

66.57, 88.77.









IR (KBr): 2990 (m), 2940 (s), 2860 (s), 2790 (s,sh), 1680 (w),

1640 (w), 1540 (s), 1460 (s,sh), 1400 (m), 1370 (m), 1345 (m), 1320

(m), 1240 (m), 1120 (m), 1050 (m,sh), 940 (w), 910 (w), 860 (m), 820

(w), 800 (w,sh), 730 (w,sh) cm-1.



Reactions Utilizing Chain-Stopping Reagents

General Procedure A: In a round-bottomed 3-necked flask

equipped with a Dean-Stark trap and a dropping funnel charged with

fresh 1,4-dioxane was placed the mixture of the starting materials,

i.e., amine component, formalin solution and nitroalkane in 1,4-

dioxane. A catalytic amount of sodium hydroxide was added and the

azeotropic mixture of 1,4-dioxane and water was distilled off with

constant addition of fresh 1,4-dioxane. When the temperature of the

outcoming vapor reached 100C, the addition was stopped and the

volume of the residual mixture was reduced to half of the original

volume by continuous distillation. Petroleum ether was added to the

reaction mixture and the upper layer was decanted. The resulting oil

was crystallized from acetone or methanol. The feed ratio of the

starting materials and reaction conditions are described in Chapter

III, p. 62.

General procedure B: In a round bottom flask equipped with a

condenser was placed the mixture of the methylol derivative of the

nitroalkane and the amine in THF. A catalytic amount of

triethylamine and 4 A molecular sieves were added. The reaction

mixture was refluxed for 10-15 hours, cooled and filtered. The

filtrate was evaporated to yield a yellow oil, which was crystallized









from acetone or methanol. The feed ratio of the starting materials

and reaction conditions are described in Chapter III, p. 62.



Synthesis of Polymers

Polymerization of 2-methyl-2-nitro-1,3-propanedio1 (19)
with N,N-dimethyl-1,3-propanediamine (32)

In a 100 ml ice-cooled round-bottomed flask was placed a

solution of 2-methyl-2-nitro-1,3-propanedio1 (19) (13.512 g, 0.10

mole) in 30 ml of 1,4-dioxane. To this, freshly distilled N,N-

dimethyl-1,3-propanediol (10.218 g, 0.10 mole) 30 ml of H20 and HC1

(6N,lml) was added. After the addition was complete, the reaction

mixture was stirred for 1 hour at 0-50C, followed by 16 hours at

70"C. The reaction mixture was cooled, made basic with sodium

hydroxide (pH 10-11), and extracted with 3x50 ml of methylene

chloride. The combined organic phase was dried over K2C03, filtered

and evaporated under reduced pressure to yield a dark brown, viscous

oil (14.23 g, 70.7% yield).

1H NMR (CDC13,TMS): 6 3.7 (s,4H), 2.75 (m,4H), 2.22 (s,6H), 1.6

(m,2H), 1.56 (s,3H).

13C NMR (CDC13,77.0): 6 24.44, 25.17, 45.10, 51.78, 56.90,

58.02, 58.85, 85.80.

IR (Neat): 2940 (s), 2880 (m), 2850 (s), 2810 (s), 2760 (s),

1540 (s), 1450 (s), 1380 (m,sh), 1340 (m), 1320 (w,sh), 1250 (m,sh),

1210 (m), 1150 (w,sh), 1120 (s,sh), 1080 (m), 1040 (m,sh), 965 (w),

910 (w), 880 (m), 870 (s), 840 (m), 730 (w,sh), 705 (w) cm'1.








Polymerization of (20) with N,N-dimethyl-1,3-propanediamine (33)

This material was prepared by the same procedure described for

(32). Thus, 14.915 g (0.10 mole) of (20) was reacted with 10.218 g

(0.10 mole) of N,N-dimethyl-1,3-propanediol to yield a dark brown oil

(13.75 g, 63.8% yield).

1H NMR (CDC13.TMS): 6 3.7 (s,4H), 2.7 (m,4H), 2.25 (s,6H), 1.75

(m,4H), 0.85 (t,3H).

13C NMR (CDC13,77.0): 6 7.09, 24.50, 30.83, 45.06, 51.88,

56.90, 57.84, 87.21.

IR (Neat): 2980 (s), 2940 (s), 2880 (m), 2860 (m), 2820 (s),

2770 (s,sh), 1540 (s), 1460 (s,sh), 1375 (m,sh), 1360 (m), 1345 (m),

1325 (m,sh), 1270 (m,sh), 1215 (m), 1155 (w), 1110 (m,sh), 1040

(m,sh), 1015 (w), 970 (w,Br), 920 (w), 890 (w), 845 (m), 810 (w), 780

(w), 750 (w), 720 (w) cm-1.

Polmerization of (19) with N,N'-dimethylethylenediamine (34)

In a 100 ml round-bottomed flask equipped with a condenser was

added a solution of (19) (8.665 g, 0.0641 mole) in 20 ml of THF and

N,N'-dimethylethylenediamine (5.653 g, 0.0641 mole). To this

solution were added a catalytic amount of NEt3 (1 ml) and 4 A

molecular sieves. The reaction mixture was brought to reflux for 20

hours, cooled and filtered. The filtrate was evaporated under

reduced pressure to yield a brown, viscous oil (9.73 g, 81.0% yield).

Analysis, calculated for C8H17N302: C, 51.33; H, 9.09; N,

22.45. Found: C, 50.45; H, 9.02; N, 22.39.

1H NMR (CDCl3,TMS): 6 1.49 (s,3H), 2.41 (s,6H), 2.58 (s,4H),

3.09 (m,4H).









13C NMR (CDCl3,77.0): 624.46, 48.10, 60.53, 65.01, 90.70.

IR (Neat): 3370 (m,br), 2980 (m), 2940 (m), 2870 (m), 2820 (m),

2800 (m), 2780 (m,sh), 1670 (m), 1645 (m), 1635 (m), 1535 (s), 1455

(s), 1395 (m), 1345 (m,sh), 1290 (m), 1270 (w), 1225 (w), 1165 (w),

1130 (w,Br), 1085 (m), 1040 (m,sh), 955 (w), 945 (w), 855 (m), 830

(w) cm-1.

Polymerization of (19) with DMBA (35)

The procedure employed for the polymer (34) was followed; thus,

compound (19) (13.860 g, 0.1026 mole) was allowed to react with DMBA

(11.714 g, 0.1026 mole) in the presence of NEt3 (3 ml) and molecular

sieves (4 A). The resulting yellow solid (14.68 g, 67.1% yield) was

dissolved in THF and reprecipitated in methanol to yield a white

powder.

Analysis, calculated for C10H19N302: C, 56.31; H, 8.98; N,

19.70. Found: C, 54.99; H, 8.84; N, 19.04.

1H NMR (CDC13,TMS): 6 1.50 (s,3H), 2.21 (s,6H), 3.0 (m,8H),

5.53 (s,2H).

13C NMR (COC13,77.0):6 19.06, 44.15, 61.45, 63.26, 93.13,

130.37.

IR (KBr): 2940 (m,sh), 2840 (m,sh), 2780 (s), 1530 (s), 1450

(s), 1335 (m,sh), 1120 (w,sh), 1070 (w,br), 1020 (s), 975 (m,sh), 855

(m,sh) cm-.

Polymerization of (19) with DMHA (36)

The procedure employed for the polymer (34) was followed; thus,

compound (19) (5.167 g, 0.0382 mole) was allowed to react with OMHA








(5.516 g, 0.0382 mole) in THF in the presence of NEt3 and 4 A

molecular sieves to yield a brown oil (6.43 g, 69.1% yield).

Analysis, calculated for C12H25N302: C, 59.23; H, 10.36; N,

17.27. Found: C, 57.62; H, 9.83; N, 17.36.

1H NMR (COC13,TMS): 6 1.33 (s,8H), 1.59 (s,3H), 2.24 (s,6H),

2.43 (s,4H), 2.81 (m,4H).

13C NMR (CDC13.77.0):6 18.86, 26.95, 27.29, 43.86, 59.89, 64.57,

93.33.

IR (Neat): 2940 (s,sh), 2850 (s), 2790 (s), 1535 (s,sh), 1450

(s,sh), 1420 (w), 1390 (m,sh), 1340 (m,sh), 1240 (w,br), 1120 (w),

1050 (m,br), 1020 (m), 940 (w), 850 (m,sh), 730 (w) cm'1.

Polymerization of (27) with DMEA (34)

Procedure A: The following procedure was modified from the

method reported by Angeloni and coworkers.26,27 In a 100 ml 3 necked

round-bottomed flask equipped with a stirrer, a condenser and a gas

inlet tube was placed a solution of compound (27) (8.057 g, 0.0426

mole) and DMEA (3.753 g, 0.0426 mole) in 70 ml of 95% ethanol.

Nitrogen gas was bubbled through the solution for 120 hours at room

temperature with constant stirring. During this period, the color of

the solution changed from yellow to dark brown. The solvent was

evaporated under reduced pressure to afford a dark brown, viscous oil

(6.07 g, 76.2% yield), which was identical with the polymer obtained

from the compound (19) and DMEA.

Procedure B: Procedure A was modified as follows: compound

(27) (7.408 g, 0.0391 mole) and DMEA (3.455 g, 0.0392 mole) were

dissolved in 50 ml of DMSO, and placed in a 100 ml round-bottomed








flask. Nitrogen gas was passed through the solution for 70 hours at

70'C. Upon heating, the color of the solution changed slowly to dark

brown. The solvent was removed by means of reduced pressure to yield

a dark brown, viscous oil (5.14 g, 70.2% yield) which was identical

with the polymer obtained from procedure (A).

Polymerization of (27) with DMBA (35)

For the preparation of this polymer, procedure (B) of the

polymer (34) was utilized. Thus, compound (27) (17.160 g, 0.0907

mole) and DMBA (10.356 g, 0.0907 mole) were allowed to react in DMSO

under N2 flow. After 70 hours at 70-800C, the reaction mixture was

poured into ice-water to yield a light brown solid (12.4 g, 64.1%

yield). The IR, 1H and C NMR spectra were identical with those of

the material obtained from the reaction between the compound (19) and

OMBA.

Polymerization of (27) with DMHA (36)

Preparation of this polymer was achieved by the procedure (A) of

the polymer (34). Thus, compound (27) (3.407 g, 0.0180 mole) and

DMHA (2.598 g, 0.0180 mole) were dissolved in 60 ml of 95% ethanol

and stirred for 96 hours at room temperature with a continuous flow

of N2 gas. The resulting solution was evaporated under reduced

pressure to yield a brown oil (2.88 g, 65.7% yield). The IR, 1H and

13C NMR spectra of which were identical with those of polymer (36)

from the reaction of (19) with DMHA.








Polymerization of (27) with piperazine (37)

Procedure A: In a 250 ml 3-necked round-bottomed flask equipped

with a condenser, a stirrer and a gas inlet tube was placed a

solution of compound (27) (11.11 g, 0.0587 mole) and piperazine (5.06

g, 0.0587 mole) in 100 ml of 95% ethanol. This reaction mixture was

stirred for 60 hours at room temperature followed by 24 hours at 50-

60"C, with continuous flow of N2 gas. During the reaction time, a

white precipitate formed. After the reaction mixture was cooled, the

solid, which is insoluble in most of the common organic solvents, was

collected (7.58 g, 69.7% yield).

Procedure B: In a 100 ml 3-necked round-bottomed flask equipped

with a condenser, stirrer and a gas inlet tube was placed a solution

of compound (27) (7.641 g, 0.0404 mole) and piperazine (3.480 g,

0.0404 mole) in 75 ml of DMSO. The reaction mixture was stirred for

60 hours at 70*C with a continuous flow of N2 gas. The reaction

mixture, which became a dark brown liquid and a yellow precipitate,

was poured into 400 ml of cold methanol. The solid was filtered,

washed with cold methanol and dried in a vacuum oven to yield an off-

white powder (5.49 g, 73.4% yield).

Analysis, calculated for C8H15N302: C, 51.87; H, 8.16, N,

22.69. Found: C, 54.98; H, 9.04; N, 24.66.

IR (KBr): 2940 (m), 2870 (m), 2800 (s,sh), 1530 (s), 1460

(s,sh), 1400 (w), 1375 (m), 1330 (s,sh), 1280 (m), 1150 (m,sh), 1100

(m), 1070 (w), 1040 (w), 1010 (s), 925 (w), 855 (m,sh), 815 (w), 650

(w) cm-1.









Reduction of Model Compounds

Reduction of compound (12b) (38)

Procedure A: The procedure reported by Parham and Ramp35 was

employed as follows: In a 100 ml 3-necked round-bottomed flask

equipped with a dropping funnel and a condenser was placed an etheral

solution of lithium aluminum hydride (4 g). A solution of compound

(12b) (8.87 g, 0.0329 mole) in 50 ml of absolute ether was added

dropwise from the dropping funnel under N2 atmosphere, and the

reaction mixture was heated at reflux for 1 hour after the addition

was complete. Water was added dropwise until the excess LiAlH4 was

decomposed, and the solution was made alkaline. The attempt to

distill the amine with steam failed. Extraction with ether yielded

an unidentifiable mixture.

Procedure B: In a 1000 ml Erlenmeyer flask was placed a

solution of sodium borohydride (5 g) in 250 ml methanol with

stirring. A solution of compound (12b) (1.68 g, 0.00624 mole) in 40

ml of chloroform was added dropwise after the addition of (a cata-

lytic amount of) palladium on charcoal. When the bubbling had

ceased, additional sodium borohydride was added. This process was

repeated several times. After the addition was complete, the

reaction mixture was stirred for 1 hour at room temperature followed

by the addition of hydrochloric acid (1 N aqueous). When the reac-

tion mixture became acidic on to pH paper, the solid (charcoal) was

filtered. The filtrate was condensed under reduced pressure to yield

a light yellow liquid. To this solution, sodium carbonate was added

until the formation of CO2 bubbles ceased (pH ~8). The resulting








solution was extracted with 3x100 ml of methylenechloride and the

combined organic phase was dried over K2CO3, filtered and dried to

afford a pale yellow oil (1.04 g, 69.6% yield).

Procedure C: In a 250 ml pressure bomb was placed a suspension

of compound (12b) (4.23 g, 0.0157 mole) in 100 ml of DMF with Raney

Ni (3 g). The bomb was charged with hydrogen gas (400 psi) and

released 3 times before being charged upto 800 psi. The reaction

mixture was stirred for 4 hours at 60*C (pressure rose to 840 psi),

then 3 hours at room temperature. The catalyst (Raney Ni) was

filtered and the filtrate was evaporated under reduced pressure at

50*C to yield a yellow oil (3.14 g, 83.5% yield).

Analysis, calculated for C14H29N3: C, 70.24; H, 12.21; N,

17.55. Found: C, 70.14; H, 12.25; N, 17.51.

1H NMR (CDC13,TMS): 6 0.96 (s,3H), 1.43 (s,8H), 1.55 (s,4H),

2.14 (s,4H), 2.48 (m,8H).

13C NMR (CDC13,77.0): 6 23.93, 25.05, 26.41, 54.97, 57.31,

67.35.

IR (Neat): 3350 (m,br,sh), 2935 (s), 2850 (s), 2780 (s,sh),

1570 (w), 1555 (w,sh), 1450 (m,sh), 1440 (m), 1380 (m), 1365 (m),

1345 (w), 1320 (m,sh), 1310 (m), 1300 (m), 1270 (w), 1260 (w), 1155

(m), 1110 (s,sh), 1055 (m,sh), 1035 (m), 1000 (m), 945 (w,sh), 890

(w,sh), 860 (m), 790 (m,sh), 770 (w) cm-1.

Reduction of compound (28) (39)

In a 450 ml parr bomb equipped with a stirrer was placed a

solution of compound (28) (21.307 g, 0.105 mole) in 200 ml of

methanol with Raney Ni (5 g). The reaction mixture was flushed with

hydrogen gas for 2 hours before the pressure of the bomb was set at








1000 psi. The reactor was heated to 50"C for 2 hours, cooled and

filtered. The filtrate was evaporated to yield a yellow oil (8.37 g,

68.7% yield) which turned out not to be the desired product but

1-(N,N-dimethylamino)-2-butylamine (39).

Analysis, calculated for C6H16N2: C, 62.01; H, 13.88; N,

24.11 Found: C, 62.11; H, 13.76; N, 24.18.

1H NMR (CDC13,TMS): 6 0.96 (t,3H), 1.42 (q,2H), 2.21 (s,6H),

2.80 (m,1H), 3.50 (d,2H).

13C NMR (CDC13,77.0): 6 10.23 (q), 28.41 (t), 45.57 (q), 49.71

(d), 66.57 (t).

IR (Neat): 3350 (s,br), 3280 (s,br), 2960 (s), 2940 (s), 2880

(s), 2860 (s), 2820 (s) 2770 (s,sh), 1660 (w), 1640 (w), 1600 (m,br),

1460 (m,sh), 1380 (w,sh), 1300 (w,br), 1265 (w), 1150 (w), 1100 (w),

1040 (m,sh), 975 (w), 910 (w), 850 (w), 780 (w) cm-.


Reduction of Polymers

Reduction of Polymer (35) (40)

Procedure (C) previously described for model compound (27) was

employed. Thus, polymer (35) (8.20 g, 0.0438 mole) in methanol was

placed in a Parr bomb with a catalytic amount (-2 g) of Raney nickel

and the bomb was charged with hydrogen upto 800 psi. The closed

system was heated to 70*C for 15 hours to afford a brown oil (5.88 g,

85.4%).

Analysis, calculated for C8H19N3: C, 61:10; H, 12.18; N,

26.72. Found: C, 60.07; H, 11.54; N, 26.10.

H NMR (DMSO-d6,TMS): 6 0.87 (s), 2.23 (s), 2.44 (s), 3.16

(s,br), 3.44 (m).









13C NMR (DMSO-d6,39.5): 6 26.68, 48.76, 52.37, 60.46, 71.47.

IR (Neat): 3400 (s,br), 2950 (s), 2860 (s), 2820 (s), 1650

(m,br), 1600 (w,br), 1460 (m), 1380 (m), 1330 (w), 1300 (w), 1280

(m,sh), 1200 (w), 1170 (w), 1130 (m), 1090 (s), 1060 (m), 1040 (m),

960 (w,sh), 940 (w), 920 (w), 890 (w), 810 (m,br) cm-1.

Reduction of Polymer (36) (41)

Procedure A: Procedure (B) described previously for model

compound (27) was employed. Thus, polymer (36) (1.68 g, 0.0079 mole)

was reduced with NaBH3CN in the presence of a catalytic amount of

palladium-charcoal to yield a light yellow oil (1.16 g, 80.3%).

Analysis, calculated for C10H21N3: C, 65.52; H, 11.55; N,

22.93. Found: C, 61.83; H, 10.75; N, 21.71

Procedure B: Procedure (C) previously described for compound

(27) was applied. In a Parr bomb was placed a solution of polymer

(36) (2.017 g, 0.00946 mole) in 100 ml of DMF with a catalytic amount

of Raney nickel. The bomb was charged with hydrogen gas to 800 psi,

and heated to 50*C for 2 hours followed by 60*C for 6 hours. The

reaction mixture was then stirred overnight at room temperature and

the catalyst was filtered. The resulting liquid was evaporated under

reduced pressure at 50%C to afford a light brown oil (1.46 g, 84.3%).

Analysis, calculated for C10H21N3: C, 65.52; H, 11.55; N,

22.93. Found: C, 64.21; H, 11.34; N, 22.20.

1H NMR (CDC13,TMS): 6 1.00 (s), 1.5 (m), 2.2 (s), 2.95 (m,br),

5.55 (s,br).

C NMR (CDCl3,77.0): 6 25.66, 45.27, 55.12, 60.87, 67.59,

130.37.









IR (Neat): 3340 (m,br), 3000 (s), 2920 (s), 2860 (s), 1700 (w),

1570 (s), 1490 (s), 1400 (m,br), 1380 (w,br), 1150 (m), 1070 (m,br),

1005 (m), 885 (m,br), 790 (w), 750 (w) cm-1.

Reduction of Polymer (37) (42)

Procedure (C) previously described for compound (27) was

applied. In a Parr bomb was placed a solution of polymer (37) (1.46

g, 0.006 mole) in 100 ml of 2-ethoxyethanol with a catalytic amount

of Raney nickel. The bomb was charged with hydrogen gas upto 800

psi, and heated to 60*C for 15 hours. The reaction mixture was

filtered and the filtrate was evaporated under reduced pressure to

yield a light yellow oil (1.1 g, 85.9%).

Analysis, calculated for C12H27N3: C, 67.55; H, 12.76; N,

19.69. Found: C, 66.16; H, 12.25; N, 19.02.

1H NMR (CDC13,TMS): 6 1.00 (s), 1.32 (s), 2.20 (s), 2.68

(s,br), 3.6 (m).

13C NMR (DMSO-d6,39.5): 6 26.83, 27.12, 45.15, 60.26, 65.52,

71.76.

IR (Neat): 3300 (m,br), 2940 (s,sh), 2860 (s), 2790 (s), 1675

(w), 1580 (w,br), 1460 (m), 1380 (m), 1350 (w), 1310 (w,br), 1270

(w,br), 1230 (w), 1120 (m,sh), 1070 (m,br), 890 (w), 850 (w,br), 730

(w) cm1.



Methylation
Methylation of Polymer (41) (43)

Procedure A: The procedure reported by Pine and Sanchez36 was

modified as follows: In a 50 ml round-bottomed flask was placed









polymer (96) (2.81 g, 0.0179 mole), and the flask was cooled in an

external ice bath. To this, formic acid (88% w/w aqueous, 3.6 g,

0.075 mole) was slowly added followed by formalin solution (37% w/w

aqueous, 5.1 g, 0.063 mole). The flask was equipped with a magnetic

stirrer and a condenser and placed in an 80*C constant temperature

bath for 26 hours. The mixture was cooled and 10 ml of 6 N HC1 was

added. This was then extracted with 3x20 ml of ethyl ether, and the

combined ether extracts were washed with 10 ml of H20 and dried over

K2C03 overnight. Evaporation of ether gave a white solid (0.23 g).

The aqueous layer was made basic with sodium hydroxide (50% w/v

aqueous) and extracted with 3x20 ml of methylene chloride. The

combined organic layer was washed with 10 ml of H20, and dried over

K2C03. Filtration and subsequent evaporation yielded a light brown,

clear, viscous oil (1.52 g, 45.9% yield).

Procedure B: The method previously reported by Borch and

coworkers37,38 was applied. To a stirred solution of polymer (95)

(2.81 g, 0.0179 mole) and formaldehyde (37% w/w aqueous, 11 ml, 0.136

mole) in 40 ml of acetonitrile was added sodium cyanoborohydride

(NaBH3CH). Glacial acetic acid was added until the reaction mixture

showed the pH of 6. Stirring was continued for 10 hours and the

mixture was poured into 200 ml of ether. The resulting mixture was

washed with 4x75 ml of KOH solution (2 N) and 1x60 ml of saturated

NaCl solution. The combined KOH wash was backwashed with 100 ml of

ether. The combined ether layer was dried over K2C03 overnight and

evaporated to yield a light brown clear, viscous oil (1.72 g, 51.9%).








Analysis, calculated for C10H23N3: C, 64.31; H, 12.51; N,

22.68. Found: C, 63.55; H, 12.18; N, 22.07.

1H NMR (CDC13,TMS): 6 0.91 (s), 2.04 (s), 2.28 (s), 2.33 (s),

2.65 (m).

13C NMR (CDC13,77.0): 6 16.67, 36.94, 46.98, 59.12, 64.04,

93.01.

IR (Neat): 3320 (m,br), 2940 (s,sh), 2840 (s,sh), 2800 (s,sh),

1660 (m), 1450 (s), 1370 (m), 1350 (w), 1325 (w), 1280 (m), 1270

(m,sh), 1235 (w), 1195 (w), 1170 (w), 1145 (m), 1130 (im), 1090

(s,sh), 1060 (m), 1040 (m), 1010 (w), 975 (w), 960 (w), 940 (w), 905

(w), 890 (m), 810 (w,br), 750 (w) cm-1.

Methylation of Polymer (42) (44)

Procedure (A) used for the methylation'of polymer (41) was

employed. Thus, polymer (41) (1.01 g, 0.0055 mole) was reacted with

formic acid (88% aqueous, 1.5 g, 0.029 mole) and formaldehyde (37%

aqueous, 2.5 g, 0.031 mole) to yield a brown oil (0.57 g, 49.0%).

Analysis, calculated for C12H25N3: C, 69.19; H, 11.92; N,

19.88. Found: C, 66.55; H, 10.89; N, 19.72.

1H NMR (CDC13,TMS): 6 1.02 (s), 2.21 (s), 2.42 (s), 2.90 (m),

5.65 (m).

13C NMR (CDC13,77.0): 6 18.33, 44.79, 45.13, 45.47, 61.56,

66.43, 93.53, 138.71.

IR (Neat): 3340 (w,br), 2940 (s,sh), 2850 (s), 2810 (s), 2785

(s), 1675 (w), 1645 (w), 1600 (w,br), 1540 (w), 1450 (s), 1360 (m),

1300 (w,br), 1260 (w), 1230 (w), 1170 (w), 1120 (m), 1095 (m), 1040

(s,sh), 1010 (m), 970 (m), 840 (w,sh), 770 (w) cm-1.









Miscellaneous Reactions

Nitroethylene (Nitroethene) (45)

The following procedure was modified from the previously

reported procedure.39,40 A mixture of phthalic anhydride (99.0 g,

.66 mole) and 2-nitroethanol (45) (49.9 g, .548 mole) was placed in a

200 ml round bottom flask equipped with a fractionating column and

distillation head. The oil bath was heated to 140-150"C and pressure

was reduced to 70-80 mmHg. After the mixture became homogeneous, the

oil bath temperature was raised to 175-180*C until distillation

ceased. The distillate was dried over CaC12 yielding a pale yellow

oil (35.8 g, 0.49 mole, 89% yield).

H NMR (CDC13,TMS): 6 5.93 (d,1H), 6.64 (d,1H), 7.21 (d. of

d,1H).

13C NMR (CDC13,77.0): 6 122.2, 144.9.

Reaction of Nitroethene (45) with Formaldehyde and Diethylamine

The method reported by Tsuchida and Tomono22 was followed. In a

100 ml 3-necked round-bottomed flask fitted with a magnetic stirrer,

a thermometer, a reflux condenser and a dropping funnel was placed a

suspension of nitroethene (1.229 g, 0.0168 mole) in 15 ml of

methanol. Alternatively, diethylamine (1.231 g, 0.0168 mole) was

dissolved in 10 ml of methanol and then formalin solution (37% w/w

aqueous, 1.366 g, 0.0168 mole) was added with cooling. To this

mixture, 1.718 g (0.0168 mole) of acetic anhydride was added. The

thus prepared amine-formalin solution was added dropwise to the

nitroethene suspension at 0*C. The reaction mixture turned reddish

brown and yielded unidentifiable tar.








Reaction of Nitroethene with Formaldehyde and Dimethylamine
Hydrochloride

The method of Tsuchida and Tomono22 was employed. Thus, the

amine-formalin solution was prepared by adding formalin solution (37%

w/w aqueous, 1.334 g, 0.0164 mole) to dimethylamine hydrochloride

(1.344 g, 0.0165 mole) in 15 ml of DMF. This solution was added

slowly to the previously prepared nitroethene solution (1.200 g,

0.0164 mole) in 20 ml of DMF, and the reaction mixture was stirred

for 2 hours at 70*C. The resulting dark brown solution was

neutralized with sodium carbonate to yield dark brown tar.

Polymerization of Nitroethene (45) (46)

Freshly distilled THF was attached to a high vacuum line,

degassed twice and transferred to a polymerization tube. Nitroethene

was distilled with CaC12 in the receiving flask and attached to the

line, degassed twice and transferred to the polymerization tube. The

previously purified pyridine (catalyst) was transferred to the

polymerization tube at -78*C. Polymerization was carried out in a

constant temperature bath (-78*C) for 1 hour. The tube was opened

and the contents precipitated into 1 N HC1 solution. The yellow

solid was collected, dissolved in DMF and reprecipitated in water.

The solid was again collected and dried in a vacuum oven (30*C)

overnight to afford an off-white powder.

Analysis, calculated for C2H3NO2: C, 32.88; H, 4.13; N,

19.17. Found: C, 32.92; H, 4.22; N, 19.10.

13C NMR (DMSO-d6,39.5):6 35.5, 81.1.

Intrinsic viscosity (DMF,25C): [n] = 0.306 dl/g.









IR (KBr): 3000 (w), 2970 (w), 2890 (w), 1550 (s,sh), 1430 (m),

1380 (w), 1360 (m,sh), 1310 (w), 1230 (w), 1050 (w,br), 845 (m), 720

(w), 690 (w) cm-1.

Reaction of Compound (24) with Methyl Isocyanate (MI) (47)

In a 100 ml round-bottomed flask was placed a solution of

compound (24) (0.895 g, 0.00249 mole) in 20 ml of DMF. A solution of

methylisocyanate (MI) (1 ml, 0.017 mole) in 15 ml of DMF and a

catalytic amount of tin octoate (TO) (5 drops) were added dropwise

over a 10 minute period. After the addition was complete, which was

done under a nitrogen atmosphere, the reaction mixture was stirred

for 10 hours at room temperature. Additional MI (1 ml, 0.017 mole)

was added and stirring was continued for 10 hours at room

temperature. Evaporation of soluent gave a light brown, viscous

liquid (0.63 g, 53.4% yield).

1H NMR (DMSO-d6,TMS): 6 1.49 (s,3H), 2.36 (s,20H), 2.48 (s,4H),

2.64 (d,6H), 2.92 (m,4H), 3.97 (t,4H), 7.98 (s,2H).

13C NMR (DMSO-d6,39.5): 6 16.75, 30.73, 53.05, 54.51, 56.56,

61.04, 62.91, 92.53, 156.62.

IR (Neat): 3340 (m,br,sh), 2950 (m,sh), 2820 (in), 1680 (s,sh),

1530 (s,sh), 1460 (m), 1420 (m), 1380 (m), 1315 (m), 1260 (m), 1215

(m), 1160 (m,br), 1095 (m), 1080 (m,sh), 1010 (w), 945 (w), 865 (w),

775 (w), 760 (w), 670 (w) cm-1.

Reaction of Compound (24) with Phenyl Isocyanate (PI) (48)

Procedure A: To a solution of compound (24) (1.797 g, 0.005

mole) and a catalytic amount (0.02 g) of freshly sublimed 1,4-

diazabicyclo(2,2,2)octane (DABCO) in 25 ml of anhydrous DMF was added









a solution of phenyl isocyanate (PI) (1.192 g, 0.010 mole) in 20 ml

of anhydrous DMF. After the addition, which was carried out under

nitrogen, was complete, the mixture was stirred for 24 hours at 60-

70*C under nitrogen. The reaction mixture was cooled to room

temperature and poured into ice-water to yield a white precipitate,

which was dried in a vacuum desiccator for 40 hours (2.36 g,

79.0%). The resulting solid was recrystallized from toluene to yield

a white powder.

Procedure B: The procedure described in (A) was used except the

catalyst, tin octoate (TO) (5 drops) was used instead of DABCO. The

white powder (2.71 g, 90.7%), which was obtained, was identical with

the compound obtained from procedure (A).

Analysis, calculated for C30H43N706: C, 60.28; H, 7.25; N,

16.41. Found: C, 59.56; H, 73.9; N, 15.30.

1H NMR (CDC13,TMS): 6 1.56 (s,3H), 2.4 (m,22H), 4.28 (t,4H),

7.1 (m,12H).

13C NMR (CDC13,77.0): 6 19.40 (q), 53.51 (t), 54.82 (t), 56.92

(t), 62.04 (t), 63.45 (t), 92.55 (s), 118.72 (d), 123.45 (d), 129.05

(d), 137.87 (s), 153.42 (s).

IR (KBr): 3630 (w), 3550 (w,br), 3330 (m,br), 3200 (w), 3140

(w), 3060 (w,sh), 3005 (w), 2950 (m), 2880 (w), 2320 (m), 1705

(s,sh), 1650 (w), 1600 (s), 1540 (s,sh), 1500 (m), 1460 (m), 1440

(s), 1405 (w), 1380 (w), 1360 (w), 1320 (s,sh), 1250 (s,sh), 1180

(w), 1155 (m), 1130 (w), 1085 (m,sh), 1060 (m), 1010 (m,sh), 940 (w),

900 (w), 850 (w,br), 755 (m,sh), 720 (w), 690 (m) cm-1.








Polymerization of Compound (24) with Hexamethylene
Diisocyanate (HMDI) (49)

To a solution of HMDI (2.152 g, 0.0128 mole) in 15 ml of

anhydrous UMF were added a solution of compound (24) (4.599 g, 0.0128

mole) in 25 ml of anhydrous DMF and 10 drops of catalyst (TO). After

the addition, which was carried out under nitrogen, was complete, the

mixture was stirred under nitrogen at 40-45"C for 60 hours. During

this period, the reaction mixture turned cloudy. The resulting

yellow, cloudy liquid was poured into ice-water to afford a white

solid (6.1 g, 92%), which was extracted with ether overnight and then

dried under reduced pressure.

1H NMR (DMSO-d6,TMS): 6 1.27 (s), 1.52 (s), 2.36 (s), 2.89 (s),

3.90 (s), 4.32 (s).

13C NMR (DMSO-d6,39.5): 6 18.59, 26.15, 29.46, 30.09, 53.15,

54.56, 56.75, 60.99, 67.13, 92.62, 136.19.

IR (KBr): 3340 (s,br), 2940 (s), 2860 (s), 2820 (m), 1720

(s,sh), 1650 (s,sh), 1580 (s), 1560 (s), 1540 (s), 1520 (s,sh), 1480

(m), 1460 (m,sh), 1380 (w), 1340 (m,sh), 1250 (s,br), 1160 (m,br),

1010 (m,sh), 930 (w), 860 (w), 775 (w), 730 (w) cm-1

Polymerization of Compound (24) with Methylenedi-p-
phenylenediisocyanate (MOI) (50)
The same method previously described for the case of (49) was

applied. Thus, compound (24) (1.799 g, 0.005 mole) and MDI (1.251 g,

0.005 mole) were allowed to react in the presence of a catalyst (TO)

for 40 hours at 45*C under nitrogen. The resulting white solid (2.6

g, 85.3%) decomposed at 180*C.









Analysis, calculated for C31H43N706: C, 61.06; H, 7.11; N,

16.08. Found: C, 59.08; H, 7.38; N, 15.24.

1H NMR (DMSO-d6,TMS): 6 1.51 (s), 2.38 (s), 3.4 (s,br), 4.16

(s), 7.2 (m), 8.5 (s), 9.5 (s).

13C NMR (DMSO-d6,39.5): 6 18.59, 53.03, 54.49, 56.46, 61.29,

62.75, 92.51, 118.32, 128.85, 134.84, 137.62, 152.54, 153.41.

IR (KBr): 3320 (m,br,sh), 3120 (w), 3040 (w), 2950 (m), 2820

(m,sh), 1700 (s,br), 1600 (s), 1540 (s), 1520 (s), 1420 (s), 1310

(s), 1230 (s,sh), 1115 (w), 1070 (m), 1020 (m,sh), 920 (w), 860 (w),

815 (m), 770 (m) cm-1.

[n] (DMSO,30"C) = 0.1944 dl/g.
Polymerization of Compound (26) with MDI (51)

The procedure described for compound (49) was employed. Thus,

compound (24) (1.608 g, 0.0059 mole) and MDI (1.477 g, 0.0059 mole)

were allowed to react in the presence of TO under nitrogen for 68

hours at 40-45"C. The resulting white powder (2.2 g, 71.3%) was

extracted with ether overnight and dried under reduced pressure.

1H NMR (DMSO-d6,TMS): 6 2.4 (s), 3.45 (m), 3.8 (s), 4.2 (s,br),

7.3 (m), 8.5 (d), 9.6 (s).

IR (KBr): 3320 (s,br), 3040 (w), 2960 (m), 2820 (m), 1720 (w),

1650 (s), 1600 (s), 1520 (s,sh), 1460 (w), 1415 (m), 1310 (m), 1240

(m,br), 1150 (w), 1120 (w), 1060 (w), 1020 (w), 1000 (m), 925 (w),

860 (w), 820 (m), 770 (m) cm-1.














CHAPTER III
RESULTS AND DISCUSSION


As indicated in the INTRODUCTION, the major objective of this

research was the preparation of new polymers containing amino groups

utilizing the Mannich reaction of nitroalkanes with formaldehyde and

a primary or a bis-secondary amine. Since this polymerization can be

classified as a step-growth polymerization, the rigorous requirements

for the successful synthesis of high polymers were expected.41-44 In

a step-growth polymerization, it is necessary to allow the reaction

to proceed to a very high degree of conversion or, in other words, to

a product that contains a very small number of functional groups.

Carothers derived a simple equation relating the degree of

polymerization to the extent of the reaction.41 If there are No

number of monomer A-A and No number of monomer B~-B molecules at the

start of the polymerization (equation 1), and at a given stage of the

reaction when there are 2 N molecules of any size remaining, the

total number of functional groups of either type which have reacted


N A-A + N Br-B + A-~AEB--B-A-~~A3 BB- (1)


is (No-N). At that point the reaction conversion, P, is given by the

ratio of the reacted number of molecules to the original number of

molecules (equation 2),










P = (No-N)/N (2)


which can be rewritten as equation (3).


N = N (1-P) (3)


The average number of repeating units in all molecules at that stage

in the polymerization, Xn, is the original number of molecules

divided by the remaining number of molecules (equation 4).


N
X n(4)


Combining these two equations gives an expression for X,, the number

average degree of polymerization, in terms of reaction conversion, P

(equation 5).



0o 1
X N (5)
n N N0(1-P) 1-P


According to this limiting equation, a reaction of 95% conversion

would give a polymer with only 20 repeating units in the average

chain.

Furthermore, the step-growth polymerization requires that an

equal concentration of reactive functional groups be maintained

throughout the reaction to produce a high polymer. This means that

not only must the reaction be initiated with stoichiometric reactant

ratios, but the system must also be free from side reactions that








selectively consume either functional group and thereby destroy the

equality of the functional group concentrations.36 This also means

that both reactants are free from impurities that might affect the

concentrations of either function group. Flory derived a similar

equation for the case in which there is an excess of one of the

monomers in an A~~A and B-~B polymerization reaction.33 Let NoA and

No,B be the respective number of monomers A--A and B~~B, and their
ratio be r. This gives the total monomer concentration N, in terms

of No,A and r (equation 6).



o 2 o,A o,B
or

1 1+r
o o,A r(6)

Since the functional groups A and B react with each other on a 1:1

basis, at a given stage of the polymerization the number of A-A

monomer reacted, NA should be equal to the number of B-B monomers

reacted, Ng. Thus the fraction of B groups that have reacted is rp

as shown by equation (8).


N
N A = P ( 7 )
o,A

NB N r'N

B oB A
o,8 o,B o,A








The total number of molecules present, N, is half of the number of

the functional groups, which must be equal to the sum of the numbers

of the unreacted A and B groups.



functional groups = (-P)NoA+(-BrP)No


Since NoB = NO,A/r, equation (9) can be easily converted into (10).



N.g = N [2(1-P)+ r (10)
f*g o,A r


Therefore,



N = N = N (1-P + 1-r (11)
2 f*g o,A 2r


As discussed previously, the number average degree of polymerization,

Xn, is given by the ratio of the total number of molecules and the

original number of molecules (equation 4). Combining equations (4),

(6) and (11) gives Xn in terms of conversion, P, and reactant ratio,

r (equation 12).


l+r
X= +(12)
n 2r(1-P)+1-r

This equation can be reduced to equation (5) when r is equal to 1.

In the case when the monomer B-B is in 10% excess, i.e., r = 0.9,

and the conversion is quantitative, i.e., P = 1, the average molecule

would have Xn of 19. In the case when the monomer B-B has 2% of

unreactive impurity, i.e., r = 0.98, and the conversion is 95%, the








average chain would have only 16.8 repeating units, compared to 20

when there is no impurity.

With this information in mind, the synthesis of model compounds

was initiated since the starting materials chosen are commercially

available.



Model Compounds

In order to obtain model compounds whose structures could be

correlated with those of analogous polymers, a series of model

reactions was carried out. The model compounds were characterized by

IR, 1H and 13C NMR and elemental analysis.

A series of reactions between 2-nitropropane, formaldehyde and

N,N-dimethyl-1,3-propanediamine (DMPA) was carried out to yield model

compound (23). The IR spectrum of this compound contains absorption

bands at 1550 cm-1 and 1450 cm-1, characteristic of the nitro

group. The 1H NMR of this compound showed a peak at 1.52 ppm which


CH
HNH 3
(CH2) + 2 HCHO + 2 CH -CH
N NO

H3C CH3

CH CH
3 C 3
H3C-C -CH2-N-- CH2-CCH
3 1 L21 2 1 3
NO2 (CH2)3 NO2

N

H3C CH3
(23)









was assigned to the four methyl groups 0 to the nitro group. The

peak at 2.18 ppm was assigned to the methyl groups attached to the

nitrogen atom. In order to determine the reaction conditions which

would afford the highest conversion, several different reaction

conditions were studied. The results are shown in Table 1.





Table 1. Reaction of 2-nitropropane with NMPD and formaldehyde.


Solvent Temp. Time Cat. % Yield


Dioxane/H20 600C 50 hrs HC1 50

Dioxane 600C 24 HC1 50
room temp. 20

Dioxane 75-800C 15 H2S04 45

Dioxane room temp. 45 K2CO3 25
reflux* 16

Dioxande room temp. 45 K2CO3 40
700C 16


* Boiling Point of 1,4-dioxane = 101C.





The higher temperature was less favorable than a lower temperature

(60-80"C) and the catalyst, being acidic or basic, did not

drastically alter the degree of conversion of the reaction. The poor

yield can be attributed to the lack of exact stoichiometry arising

from the formaldehyde concentration as well as the complexity of the

system. To reduce the complexity of the system, thereby reducing the








possible weighing error and exact stoichiometry, the methylol

derivative of 2-nitro-propane was utilized. Compound (18)


CH3

CH3 CH

NO2


CH3

+ HCHO ---> CH3-CCH2OH

NO2

(18)


which is an adduct of 2-nitropropane and formaldehyde was obtained in

almost quantitative yield. This then was reacted with DMPA to afford

the same product (23) in much improved yield. Results are shown in


(18) +


HNH

I
(CH2)3
N
H3C CH3

(DMPA)


----> (23)


Table 2. Reaction of (18) with DMPA.


Solvent Temp. Time Cat. % Yield


Dioxane/H20 700C 18 hrs 50

Dioxane/H20 700C 22 NaOH 70

THF refluxa 24 N(CH2CH3)3 90

THFb room temp. 70 N(CH2CH3)3 85


a Boiling Point of THF = 66*C.
b 4 A molecular sieves were added.








Table 2. The presence of a catalytic amount of base increased the

conversion while the longer time had little impact.

The ethanolamine derivative, i.e., N-methylethanolamine, was

reacted with compound (18) to afford the 1:1 adduct, N-(2-

hydroxyethyl)-N-methyl-(2-methyl-2-nitro-1-propy1)amine (21), in good

yield. The 1H and 13C NMR spectra and the assignment of the peaks

are shown in Figures 1 and 2. The IR spectrum shows typical nitro

peaks at 1530 and 1370 cm-1. The yield of this reaction ranged from

60% to 77%. The reaction conditions and yields are shown in Table 3.


CH
1 3
HNCH2CH2OH


CH CH CH
| 3 1 3 1 3
+ CH3-C-CH2 OH ---- CH3-C-CH2-N-CH2CH2OH

NO 2 NO 2
N02 2N0
(21)


Table 3. Reaction of N-methylethanolamine and compound (18).


Solvent Temp. Time Cat. % Yield


THF 66oCa 20 hrs NEt3 77

THFb room temp. 72 NEt3 67

THFb room temp. 72 60


a Reflux
b Molecular sieves (4 A) were added.





60






e




c c
CH3 CH3
a b 3d e


NO2



d







a
b








5.0 4.0 3.0 2.0 1.0 0.0 ppn


Fig. 1. 1H NMR spectrum of compound (21) in CDC13.















C
CH 3 CH3f,
a b I j 3
HO-aCH2CH-N-CHC-CH3

NO2


be


CDC13
'^^3


0 ppn


Fig. 2. Completely decoupled 13C NMR spectrum of compound (21)
in CDC13.


100


I I -I 1. I I -








N-methylethanolamine was reacted with the methylol derivative of

nitroethane, i.e., 2-methyl-2-nitro-1,3-propanediol (19) to afford

2:1 adduct (22) in good yield (72.4%). Since the given % yield is

the separated yield, actual conversion should be higher.


CH3 CH3 CH3 CH3 CH
3 3 3 H3
HN-CH2CH20OH + HOCH2C-CH2 OH --> HOCH2CH2NCH2CCH2NCH2CH2OH

NO2 NO2

(22)

Model Compounds with 2-Nitropropane as Chain-Stopping Reagent

Piperazine, a bis-secondary amine, was reacted with formaldehyde

and 2-nitropropane to form the 1:2 adduct, compound (13). The 1H NMR

spectrum showed three singlets of methyl groups, methylene groups and

piperazine-methylene groups at 1.54, 2.47 and 2.83 ppm, respectively

(Fig. 3). The 13C NMR spectrum is shown in Figure 4 with its peak

assignment. Both piperazine and 1-nitropropane are difunctional

compounds and thus will react to form a polymer in the presence of

formaldehyde, while 2-nitropropane is a mono-functional compound and

thus will stop the chain propagation. Assuming that the reactivity

of 2-nitropropane proton is equal to those of 1-nitropropane protons,































'IMS


5.0 4.0 3.0 2.0 1.0 0.0
pun


Fig. 3. 1H NMR spectrum of compound (13) in CDC13.


I- CH c MHj.
CH C-CH- N2-N -CHC

NO 2 NO2






























CDC1


100


6I
60


20


Fig. 4. Completely decoupled 13C NMR spectrum of compound
in CDC13.


TMS


I I
0 pan


(13)


I r 1 1 ..,..









CH

2CH3CH + 2 HCHO + HN NH

NO2

CH CH
OHI3 | H3
CH3-C-CH2-N N-CH2-C-CH3
NO2 NO2

(13)

a series of model compounds was synthesized. The repeating units of

these model compounds should come from the reaction of 1-nitropropane,


CH3
n CH3CH2CH2NO2 + (n+1) HN NH + (2n+2) HCHO + 2 CH3CH

NO2


CH3
I
CH3 CH2 CH3

SCH3C-CH2 N--CH2C-CH2N N---CH2CCH
3 \_ 2I 3
NO2 n n NO2

n = 1, 5, 20 and 100


with 2-nitropropane serving as a chain-stopping reagent. By varying

the ratio of reactants, one can theoretically control the length of

the chain, or in other words, the number of the repeating units. As

shown in Figure 5, the 1H spectra of these compounds can be utilized

to determine the actual number of the repeating units from the

integration of the different methyl peaks. The triplet at 0.97 ppm


























n= 1


n= 5


n = 20


n = 100


8.0 6.0


4.0


2.0


0.0
PPn


Fig. 5. 1H NMR spectra (in CDC13) of the model compounds utilizing
2-nitropropane as chain-stopping reagent.


10.0








represents the methyl group of the repeating units while the singlet

at 1.54 ppm represents the methyl groups at the end of the

molecule. From the integration of these two peaks of each spectrum,

the ratios of 4:1, 5:6, 1:4 and 1:9 were obtained for the theoretical

degrees of polymerization of 1, 5, 20 and 100, respectively. In

other words, the actual degrees of polymerization of these compounds

were 1, 5, 16 and 36, respectively, as shown in Figure 6. Similarly,

another bis-secondary amine, i.e., N,N'-dimethylethylenediamine was

reacted with formaldehyde and 1-, and 2-nitropropane to yield the

corresponding model compounds. When n=0, i.e., 1-nitropropane was


CH3 CH3 CH3

n CH3CH2CH2NO2 + (n+1) HNCH2CH2NH + (2n+2) HCHO + 2CH3CH

NO2

CH
3 -
CH3 CH3 CH3 CH2 CH3 CH3 CH3

S CH3CCH2NCH2CH2N --CH2CCH2NCH2CH2N CH2CCH3
|1 C 1 1
NO2 NO NO2

n = 0, 1 and 20.


not used, the white powder of N,N'-dimethyl-N,N'-bis(2-methyl-2-

nitro-1-propyl)ethylenediamine (30) was obtained. The 1H NMR and 13C

NMR spectra are shown in Figures 7 and 8, with peak assignment. In

the other two cases, a similar result was obtained when same method

of analysis was applied to their 1H NMR spectra. The ratios of the

methyl peak at 0.97 ppm and 1.55 ppm are 4:1 and 3:11 for the



















120

110 -

100 ----- Theoretical /
Actual /
90 -

.80 -

70-

o 60 -

S50 -

40 -

30 -

20 '

10

0I I
0 10 20 30 40 50 60
Reactant Feed Ratio










Fig. 6. Plot of the number of repeating limits vs. reactant feed
ra ti o.
















C C
a -vc 3 CH c a
4 b I 3b 3 a
CHC -CH2-N-CHCH-N-CH C.

NO2 NO 2


4.0


2.0


Fig. 7. 1H NMR spectrum of compound (30) in CDC13.


IMS


5.0


1.0


0.0
ppm


I


I














d d
a 3e aa
a )cH -I IC N I 'H
CH ccHM-N-CHC-Nc

2 NO2


CDC13
I i


A. I


120 2


LOO


60 40


Fig. 8. Completely decoupled 13C NMR spectrum of compound (30)
in CDC13.


20I ----0
20 0 -p)En


1 r


Jjl








theoretical chain length of 1 and 20, respectively. In other words,

the calculated chain length of 1 and 15 is obtained for these

compounds. The result shows that (A): the reactivity of the protons

of 1-nitropropane is less than that of 2-nitropropane, thus the

propagation stops before all the presenting 1-nitropropane is

consumed, and more probably (B): the reaction conversion is not

100%; therefore the growth of the chain stops before all the

reactants are consumed.

Model Compounds with N-(B-Hydroxyethyl)piperazine

Nitroethane was reacted with formaldehyde and N-(8-

hydroxyethyl)piperazine (NHEP) to afford 1:2 adduct (24). The IR

spectrum of this compound shows the characteristic peaks of the nitro

group at 1530 and 1330 cm-1. The 1H NMR spectrum, as shown in Figure

9, shows a singlet at 1.59 ppm which is assigned to the methyl

protons. The other singlet at 2.51 ppm is from the methylene


CH CH NO + 2 HCHO + 2 HN NCH CH OH
3 2 2 2 2

CH3

>--- HOCH2CH2N NCH2CCH2N CH CH OH
NO

(24)

protons of the piperazine ring while the triplet at 3.59 ppm is from

the methylene protons of the substituted ethanol moiety. The 13C NMR

spectrum and the peak assignment are shown in Figure 10.

A similar result was expected when 1-nitropropane was reacted

with formaldehyde and NHEP. The white solid which separated first













lMS



b,c








ab
C ca, c
a b /--\ dI /-\ b a


N2







a
d





5.0 4.0 3.0 2.0 1.0 0.0 ppn







Fig. 9. 1H NMR spectrum of compound (24) in CDC13.














CDC1
c,d







c d i3 d c
a b /--\efle b a
H 2CH N 2 nHO NCH 2 CH2 OH
\b/ 21 \JL
b,e NO
NO2

a


IMS

f g







100 80 60 40 20 0 PPn












Fig. 10. Completely decoupled 13C NMR spectrum of compound (24)
in CDC13.









from the reaction mixture turned out to be compound (26) instead of

compound (25). The IR spectrum of this compound does not include

the characteristic peaks of the nitro group, and the 1H NMR spectrum

does not have the typical triplet, characteristic of methyl protons

of the ethyl group. The 13C spectrum of this compound shows that

there is neither primary nor quaternary carbon. This was confirmed


CH3CH2CH2NO2 + 2 HCHO + 2 HN NCH2CH2OH


H 3
CH3

HOCH2CH2N NCH2CCHN NCH2CH2OH

NO2

+ (25)


HOCH CH N NCH N NCH CH OH
S2 LJ 2 ./ 2 2
(26)

by the off-resonance 13C spectrum, as shown in Figure 11. Compound

(25) was separated from the reaction mixture afterwards in low

yield. Compound (26) is a condensation product of formaldehyde and

NHEP, and a similar reaction is known to occur between formaldehyde

and piperidine.45,46 In order to avoid the formation of the unwanted

product (26), the preformed methylol derivative of 1-nitropropane

(20) was reacted with NHEP. In this case, there is no free

formaldehyde, and therefore little condensation between formaldehyde

and NHEP was expected. However, both (26) and (25) were separated

from the reaction mixture despite the fact that the yield of (25) was













DMSO
IEs


c,d
. I


a b e b a
M-RCH t N-CH2-N NICHCH^OH


I I


' I LI


140 120 100 80
J L_ -


60


11 I


20 0 ppn


Fig. 11. 13C NMR spectra of compound (26) in DMSO-d6:
completely decoupled; (2) off-resonance.


24S


160


I -~~I~CCILee


t I I


----Y








higher than in the previous reaction. The presence of this

condensation product (26) indicates that the methylol derivative of

1-nitropropane is actually in equilibrium with formaldehyde and 1-

nitropropane and thus presents the chance of condensation between


CH OH CH2OH
I2 1 2
CH 3CH2C-NO2 CH2CH2C-NO2 + HCHO
CH2 OH H


HOCH2CH2N N NH + HCHO ---- HOCH2CH2N N CH2OH


/ 1
HN NCH2CH2OH



HOCH CH2N NNCH2CHN N CHOH

(26)

formaldehyde and NHEP. For compound (25), the IR, 1H and 1C NMR

spectra confirm the structure by the characteristic peaks of 1530 and

1330 cm-1 for the nitro group, a triplet characteristic of the methyl

protons of the ethyl group, and a peak for the primary carbon at 7.97

ppm and another at 94.87 ppm for a quaternary carbon, respectively.

In order to determine which reaction conditions result in higher

conversion, a series of the condensation between NHEP and compound

(19) was followed by NMR. Since the chemical shift of the methylene









CH
\3 |NaOD/D20
HOCH2CH2N NH + HOCH2CCH OH THF-d8 (24)
t L / 2 2 THF-d8
NO or
DMSO-d6
(19)

protons adjacent to oxygen remained virtually unchanged, the triplet

corresponding to these protons was used as reference. As shown in

Figure 12, the relative intensity of the peak corresponding to the

methylene protons next to NH decreased as the reaction proceeded.

The result is shown in Figure 13. The reaction was not affected much

by the solvent since there is not much difference in conversion

between the solvents, THF and DMSO. The highest conversion was

observed at 60*C rather than at 1000C, probably due to the reversible

reaction.

Since NHEP can be used as a chain-stopping reagent, a series of

model compounds from nitroethane, formaldehyde, piperazine and NHEP

was preparated. When a feed ratio of piperazine to NHEP was 5:2 so


(n+1) CH3CH2NO2 + (2n+2) HCHO + n HN NH + 2 HN NCH CH OH
.-\_/ J/ 2 2

/\ CH3 CH3 13
--- > HOCH2CH2NNCH2CCH -F--N NCHCCH---N N CHCH OH
HC2CH2N NH 2 2 N/ N2(II 2 2



















































5.0 41.0 3.0 2.0 1.0 0.0
PPn




Fig. 12. Selected time dependent 1H NMR spectra of the reaction of
NHEP with compound (19) in DMSO-d6 at RT.



































oa
\ vo w ^o

























<1
OQCO









0


O


O
i.1
4
bO4


0 0 0
W l C


d3mN EtUBU.t gO %








that the expected degree of polymerization was 5, a white precipitate

formed during the reaction. This solid was not soluble in most of

the common organic solvents, i.e., acetone, toluene, ether, methanol,

THF, DMF, chloroform and acetonitrile. A similar result was obtained

from the reaction when a feed ratio of 10:1 was utilized. Both of

these products are soluble in HC1 (10% w/v aqueous) solution. The

viscosity measurement in 10% HC1 at 25*C resulted in intrinsic

viscosities of 0.0025 dl/g and 0.0024 dl/g, respectively. In other

words, the molecular weights of the compounds were about equal. This

can be explained by the fact that the solid product precipitated out

during the reaction, and therefore the propagation of the chain

stopped before the average chain length of 5 was attained.

Studies with Nitromethane

As discussed previously, the methylol derivative of a

nitroalkane (20) is in equilibrium with formaldehyde and 1-

nitropropane. If this is true in the case of the derivative of

nitromethane, a mixture of mono-, di-, and trisubstituted product

should result from the reaction between 2-nitro-1,3-propanediol (15)

and piperidine. An attempt to synthesize (18) by direct condensation

of nitromethane with formaldehyde failed since the product was mainly

the trisubstituted compound, i.e., 2-(hydroxymethyl)-2-nitro-1,3-

propanediol (16).


K2C03
CH3NO2 + HCHO ---- (HOCH2 )3CNO2

(16)








However, the desired diol (15) was obtained when this compound (16)

was treated with sodium, followed by salysilic acid. The IR spectrum

of this compound shows peaks at 1540 and 1360 cm-1 characteristic of

the nitro group. The 1H NMR spectrum shows a muliplet at 3.72 ppm



Na ( 00OOH
(HOCH2 3CNO2 -- a > (HOCH2 2CNO2 >H > (HOCH2 2CHNO2
CH3 OH ether

(16) (17) (15)

assigned to the methylene protons, a pentet at 4.66 ppm assigned to

methine proton, and a triplet assigned to the hydroxyl protons. This

triplet vanished when a drop of 020 was added to the NMR tube, thus

confirming that the signal is from the hydroxyl protons (Fig. 14).

The 13C NMR spectrum shows two peaks at 59.56 and 91.92 ppm, assigned

to methylene carbons and methine carbon, respectively. This

assignment was confirmed by the off-resonance 13C NMR spectrum (Fig.

15). This compound (15) was then reacted with piperidine to yield a

mixture of mono-, di-., and trisubstituted product as expected. The

amount of disubstituted product was increased when the reaction

temperature was lower.

Model Compounds from Bis-secondary Amines

N,N'-dimethyl-2-butene-1,4-diamine (DMBA) and N,N'-

dimethylhexamethylenediamine (DMHA) were also utilized in the model

compound studies. A reaction between 2-nitropropoane, formaldehyde

and DMBA afforded the model compound (31) in good yield. The IR

spectrum of this compound shows two peaks at 1530 and 1340 cm-1
















C
H
abi ba
HOCH2 -C-H2OH

NO2




(2)





a b

IMS



H20


C
DMSO
(1)




7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0




Fig. 14. 1H NMR spectra of compound (15) in DMSO-d6: (1) without
D20, (2) 1 drop of D20 was added.

















H

HO-CH -C-CH OH

N2


DMSO




















IMS


I I I I


120 100


80 60


Fig. 15. 13C spectra compound (15) in DMSO-d6:
decoupled, (2) off-resonance.


(1) completely


140


(2)


20 0 pn


bw _W __ NWWI_ ~ _~_








CH3 CH3 CH3

2 CH3-C-H + 2 HCHO + HN-CH2CH=CHCH2N-H
NO2


CH3 CH3 CH3 CH
S33 3 I 3
___ CH CCH NCH CH=CHCH NCH CCH
31 2 2 2 2i 3
NO2 NO2

(31)

characteristic of the nitro group. The 1H NMR spectrum shows a

multiple at 5.52 assigned to the protons on the carbon-carbon double

bond (Fig. 16). The 1C NMR spectrum also shows the C-C double bond

at 130.41 ppm (Fig. 17). Similarly, DMHA was reacted with 2-

nitropropane and formaldehyde to yield compound (34) in fair yield.

The IR spectrum shows the characteristic peaks of the nitro group at


CH CH CH CH CH CH3 CH
1 I 3 3 3 3 I
2 CH3CH + 2 HCHO + HN(CH2 6NH --> CH3CCH2N(CH2 )NCH2CCH3
NO2 NO2 NO2

(32)

1540 and 1345 cm-1. The 1H NMR spectrum includes peaks at 1.30,

1.58, 2.26, 2.42 and 2.83 ppm, assigned to the methylene protons from

the middle of the amine moiety, methyl protons from the nitropropane

moiety, methyl protons attached to nitrogen, methylene protons

attached to nitrogen, and other methylene protons attached to

nitrogen, respectively. The 1C NMR spectrum and the peak

assignments are shown in Fig. 18.




















L l1 I I i a
CH3CCHZ 2 21CH=H-NC 3i
1 b d b i
2e N2











e d


6.0
6.0


5.0


4.0
4.0


3.0


Fig. 16. 1H NMR spectrum of compound (31) in CDC13.


a9


TMS


2.0


1.0


0.0


ppn


C
















a" 3dF H d .3 a


f 2I

f








(1)
''~rriWM~tw4'*^ .


CDCl3


*ivwPA WYv


i i- I i i--- -i I I
200 180 160 140 120 100 80 60 40 20 0 ppn


(2)



















Fig. 17. 13C NMR spectra of compound (31) in CDC13: (1) completely
decoupled, (2) off-resonance.


c,e d









OMW^vv


MS




























IMS


I i i I I I I
120 100 80 60 40 20 0
ppn



Fig. 18. 13C spectra of compound (32) in CDC13: (1) completely
decoupled, (2) INEPT (CH,CH3 pos., CH2 neg., C, solvent
suppressed).









Polymers

An investigation of the polymerization of NMEA with (19) was

then carried out. The reaction, which was refluxed in THF (66*C) for

24 hours in the presence of molecular sieves (4 A), gave an



CH 3 CH 3 CC 3 CH CH CH 3
1 1 1 3 3 1
HNCH2CH2NH + HOCH2CH22H 2 2CCHNCH2CH2 -

NMEA NO2 NO2
(19) (35)

excellent yield of polymer (35). The infrared spectrum of the brown,

viscous oil shows IR absorptions at 1535 and 1345 cm-1 characteristic

of the nitro group, and is very similar to that of model compound

(30). The 1H NMR spectrum is also very similar to that of model

compound (30) and the peaks are assigned accordingly, i.e., the

singlet at 1.5 ppm to the methyl protons of the nitroethane moiety,

the singlet at 2.3 ppm to the methyl protons next to the nitrogen,

the singlet at 2.4 ppm to methylene protons of the amine moiety and

the singlet at 2.9 ppm to the methylene protons from the

formaldehyde. The 13C NMR spectrum shows five major peaks, which are

in agreement within 3 ppm to those of the 13C NMR spectrum of

compound (30) (Fig. 19). This polymer, however, showed a molecular

weight of only 2200 by vapor pressure osmometry. The low molecular

weight can be the result of the relatively low conversion (~90%).

NMBA and (19) was then polymerized under identical conditions to

afford polymer (36). The very viscous yellow oil shows IR

absorptions at 1530 and 1335 cm-1 characteristic of the nitro group.












a


.cd

Ia c I I






(1) b 3C1


120 100 80 60 40 20 0
PPn






















Fig. 19. 13C NMR spectra of polymer (35) in CDC13: (1) completely
decoupled, (2) off-resonance.









CH3 CH3 CH3 CH3 CH3
HNCH2CH=CHCH2NH + (19) CH2CCH2NCH2CH=CHCH2N

NMBA NO2 -,x
(36)

The 1H NMR and 13C NMR spectra are very similar to those of the model

compound (31), and peaks are assigned accordingly. The 13C NMR is

shown in Fig. 20. This polymer showed a low molecular weight (~2500)

by VPO, which can also be attributed to the low conversion.

Similarly, NMHA and (19) was polymerized under identical

conditions to yield polymer (37). The viscous brown oil also shows

characteristic nitro absorptions in IR, and 1H and 1C NMR spectra

are also similar to those of the corresponding model compound (32).


CH CH CH CH CHC
H3 H3 3 13 H3
HN(CH2)6NH + (19) --> --CH2CCH2N(CH2)6N

NMHA NO2 _x
(37)

The polymerization between N,N-dimethyl-1,3-propanediamine and (20)

yielded a similar result. Polymer (33) was identified by IR, 1H and

13C NMR spectra according to the corresponding model compound (23).

Since these polymers, obtained from the condensation of amine and the