Acylation of amino-1,2,4-triazoles

Article abstract of DOI:10.1023/A:1012335318926

A scheme of acylation of amino-1,2,4-triazoles under conditions of low-temperature polycondensation is proposed. The effect of reaction conditions on the yield and properties of reaction products is established.

Full text of DOI:10.1023/A:1012335318926

Russian Journal of General Chemistry, Vol. 71, No. 4, 2001, pp. 557 566. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 4, 2001,
pp. 600 609.
Original Russian Text Copyright
2001 by Barmin, Kartavykh, Korolev, Tugai, Grebenkin, Mel’nikov.
Acylation of Amino-1,2,4-triazoles
M. I. Barmin, V. P. Kartavykh, E. A. Korolev,
I. D. Tugai, A. N. Grebenkin, and V. V. Mel’nikov
St. Petersburg University of Engineering and Design, St. Petersburg, Russia
Received March 25, 1998
Abstract A scheme of acylation of amino-1,2,4-triazoles under conditions of low-temperature polycon-
densation is proposed. The effect of reaction conditions on the yield and properties of reaction products is
established.
Regardless of conditions, polycondensation reac-
tions are complicated and not infrequently multidirec-
tional, as a result of interplay of a lot of variables and
interrelated factors. Therefore, investigations in the
field of polycondesation processes are much more
descriptive than is common in the chemistry of
monomers. Attempted modeling of such systems has
been mentioned in [1, 2].
The rigorously substantiated ability of aminotri-
azoles to be acylated both by exocyclic amino groups
and by the ring imino group [7] is also characteristic
of their reactions with acid dichlorides. The reactions
of 5-amino-1,2,4-triazole with adipoyl, sebacoyl,
fumaroyl, and terephthaloyl chlorides under condi-
tions of low-temperature polycondensation in dry
dimethylacetamide give low-molecular polyamides
containing nonequivalent amide ( NH CO ) and
imide >( N CO ) units. Such result can arise only if
the reaction occurs by the following scheme: I stage:
reaction between the monomers; II stage: reaction
between the dimers; etc.
In such a situation growing in importance is search
for empirical relationships between characteristics of
the polymer formed (such as yield and molecular
weight) and reaction conditions. It should be em-
phasized that reactions leading to polyamides of the
1,2,4-triazole series is difficult to study because of the
ambident reactivity of aminotriazoles in elementary
acylation (amidation) stages. Therefore, in our study
on polyamidation involving dicarboxylic acid chlori-
des and diamines of the 1,2,4-triazole series we
focussed, along with regular trends in polymer forma-
tion, on the reactivity of aminotriazoles in acylation
reactions.
Alternatively, polyamides from aminotriazoles and
dicarboxylic acid chlorides may by formed by diacyla-
tion of the amino group [8]. However, this scheme
was proposed for the strongly basic aliphatic amines
[7] and is unlikely with the weakly basic aminotri-
azoles.
According to speculations in [8, 9], acylation of
5-amino-1,2,4-triazole with carboxylic acid chlorides
Oligoamides I XXXV were prepared by known
procedures [3 6].
N
R R NH CO Y CO ]n
[ R
H
N N
I XXXV
R, R and R are absent (I, VIII, XV, XXII, XXIX); R = R = NH, R is absent (II); R = R = NH, R = triazol-3,5-
diyl (III); R = NH, R = CH2, R = triazol-3,5-diyl (IV); R = NH, R = (CH2)2, R = triazol-3,5-diyl (V); R = NH, R =
(CH2)4, R = triazol-3,5-diyl (VI); R = NH, R = (CH2)8, R = triazol-3,5-diyl (VII); R = NH, R and R are absent (IX,
XVI, XXIII, XXX); R = NH, R is absent, R = triazol-3,5-diyl (X, XVII, XXIV, XXXI), 3-methylenetriazol-5-yl (XI,
XVIII, XXV, XXXII), 3-(tetramethylene)triazol-5-yl (XII, XIX, XXVI, XXXIII), 3-(octamethylene)triazol-5-yl (XIII,
XX, XXVII, XXXIV), 3-(propenylene)triazol-5-yl (XIV, XXI, XXVIII, XXXV); Y is absent (I VII), (CH2)4 (VIII
XIV), (CH2)8 (XV XXI), p-C6H4 (XXIX XXXV); n = 3 7 (I XXXV).
1070-3632/01/7104-0557$25.00 2001 MAIK Nauka/Interperiodica

558
BARMIN et al.
I stage
N
ClOC Y COCl
NH CO Y COCl
N
HN
NH2
N
N
N NH
NH2
ClOC Y COCl
N
ClCO Y CO
N
N
II stage
N
N
N CO Y COCl
NH CO Y CO NH
N
N
HN
N
N
N
NH2
N
+
N
ClCO Y CO
NH CO Y COCl
NH2
N
HN
N
N CO Y CO
ClCO Y CO NH
N
N
proposed in [8], the first stage of the reaction results
exclusively in N-acyltriazole formation, then, evident-
ly, under conditions of gas liquid and liquid liquid
phase-transfer condensations no polymers would form
at all,1 and the reaction would involve no other pro-
cesses as aminotriazole-catalyzed hydrolysis of acid
chloride.
NH CO R
N
N
N NH
NH2 ClOC R
N
H
N
R CO N OC R
ClOC R
N
N
H
N
occurs initially by the ring to give 1-acyl-3(5)-amino-
1,2,4-triazole. Then the acyl chloride moiety can
migrate to the exocyclic amino group, yielding 3-
acylamino-1,2,4-triazole; therewith, the transacylation
is always intramolecular [8, 10, 11]. Note that, as
follows from [8, 10], the acyl migration from the ring
Meanwhile, it is such puttern which we observed
to the exocyclic NH2 group is favored by electron- in the gas liquid and liquid liquid reactions of
acceptor substituents R.
5-amino-1,2,4-triazole with dicarboxylic acid chlori-
des: Istead of expected 1,2,4-triazole polymers we ob-
tained intractable mixtures of di- and trimers with an
average molecular weight of up to 300.
The reactions of diaminotriazoles with dicarboxylic
acid chlorides involve acylation of the endocyclic NH
group, resulting, finally, in termination of polymeric
chains in the course of synthesis or isolation of the
polyamides. Here, however, a concurrent irreversible
polyamidation via acylation of exocyclic amino
groups takes place, and, moreover, cleavage of the
azolide groups is prevented by the electron-acceptor
effect of the two amino groups [13]. Under these
circumstances one can expect formation of triazole-
containing oligoamides in high yields.
Our results, namely the synthesis of oligoamides
under various conditions, in aqueous-alkaline solu-
tions inclusive, suggest that aminotriazoles are not
only acylated by the ring but also directly by the
exocyclic amino group. Actually, if the only target
for attack by the acyl group is the heteroring, i.e., as
1
As shown in [12], 50% of azolide groups in N-acetyltriazole
are hydrolyzed in straight water within 6 min, while in
0.001 N KOH solution an almost immediate hydrolysis takes
place.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001

ACYLATION OF AMINO-1,2,4-TRIAZOLES
Thus, the oligomer formation [10, 11] in various
559
conditions of nonequilibrium polycondensation
suggests comparable probabilities of acylation by exo-
cyclic and exocyclic amino groups. Therefore, to ob-
tain high-molecular aminotriazoles, we should inac-
tivate the imino group in the triazole ring by acylation
and thus direct the reaction between diaminotriazoles
and dicarboxylic acid chlorides exclusively on the
way of amidation.
Yield, %
80
1
70
60
3
2
4
5
50
6
In principle, there are two possible approaches to
this problem. The first involves substitution of the
mobile proton of the 1,2,4-triazole ring in diamino-
triazole molecules by a neutral substitutent, such as
alkyl. However, this trivial approach fails with amino-
triazoles: The latter tend to tautomeric transformations
and thus a probabilty exists that the ring contains an
imino group susceptible to electrophilic substitution.
This is in line with our concept [13, 14] that amino-
azoles in solution are present in the imino form.
0
10 20
30
40
50
60
Temperature, C
Fig. 1. Yield temperature plots for oligoamides (1) XIV,
(2) XV, (3) XXI, (4) XXII, (5) XXVIII, and (6) XXIX.
Thus, analysis of the dependences of the yield and
molecular weight of the synthesized compounds on
reaction conditions shows that high-molecular poly-
amides are principally impossible to obtain by non-
equilibrium polycondensation in force of the intrinsic
dual reactivity of aminotriazoles in elementary acyla-
tion acts and the presence of the imino form in solu-
tions. The concentration of monomers in the range
studied (0.01 0.30 M) has almost no effect on the
yield and molecular weight (specific viscosity) of
1,2,4-triazole oligoamides. The observed insignificant
variations in the yield (up to 3 4%) fall within the
experimental error.
The second approach is to perform the reaction in
conditions favoring the target polyamidation reaction
and unfavoring the side heteroring acylation reaction.
Since aminotriazoles are protonated exclusively by
ring nitrogens, it was not unreasonable to suggest that
in acid medium aminotriazoles would be acylated
exclusively by amino groups. However, the experi-
mental dependences of the yield of oligomers on the
pH of the medium showed that the yield is sharply
reduced in the absence of alkaline acceptors, while in
acid medium no polyamidation takes place at all [4, 5].
The fact that the yield of 1,2,4-triazole oligoamides
is independent of monomer concentration can be
explained by early chain termination. Further heating
enhances mutual solubility of the aqueous and organic
phases, thus enhancing hydrolysis of acid chlorides
and reducing the yield and molecular weight of poly-
mers [1]. As seen from the temperature dependences
of the yield (Fig. 1), the polycondensation involving
diaminotriazoles and dicarboxylic acid chlorides fits
this regularity. At temperatures higher than 20 C the
yield of oligoamides sharply decreases. At the same
time, at reduced temperatures (5 15 C), too, slightly
decreased yields are observed.
Evidently, such result is explained by the fact that
the electron pair of the amino group in aminotri-
azoles is conjugated with the -electron system of the
heteroring. Therefore, ring protonation reduces the
basicity not only of ring heteroatoms but also of exo-
cyclic amino groups, thereby reducing the reactivity
of the latter toward acid chlorides [15]. Simultaneous-
ly hydrolysis and other side reactions involving acid
chlorides increase in importance. This all results
finally in reduced molecular weights of oligomers.
However, it should be emphasized that regarless of
polyamidation procedure and conditions the Mn of all
the synthesized oligoamides is no higher than 2000.
This value could not also be increased by using purer
monomers.
It should be noted that the temperature yield
curves for the gas-phase and liquid-phase polyamida-
tions have different shapes. In the gas liquid system,
the yield increases with temperature, while in the
liquid liquid system, a smooth maximum is observed
at about 20 C. Such difference was first observed in
[1, 15] in the synthesis of polyhexamethyleneoxamide
and explained by different temperature effects on the
mutual solubility of the phases and thus on the degree
of hydrolysis of acid chlorides.
The main side reaction in the polyamidation involv-
ing diaminotriazoles and dicarboxylic acid chlorides is
acylation of the triazole ring, which under conditions
of phase-trasfer polycondensation gives rise to hydro-
lysis of the acid chlorides, while in polycondensation
in solution, to formation of unstable azolide units
whose cleavage results in the degradation of the
macromolecules into oligoamide fragments [10].
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560
BARMIN et al.
The experimental data show that the reactions of
Yield, %
90
diaminotriazoles and adipoyl chloride yield polymeric
products only in the presence of HCl acceptor (NaOH);
therewith, the highest yield is attained at a 2:1
NaOH:diamine molar ratio in the aqueous phase, in
agreement with published data [1, 16, 17]. The the
molecular weight (specific viscosity) of oligoamides
proved invariable within error, i.e., independent of the
pH of the aqueous phase.
XV
XXII
70
40
XXIX
For successful polycondensation in solution, two
conditions should be met. First, starting monomers
should be soluble in the solvent to be used and,
second, there should be almost no reactions between
the solvent and the starting reagents. In all syntheses
we applied the same reagent mixing scheme, when a
solid or a liquid acid dichloride was added with stir-
ring in one portion to a solution of diamine in di-
methylacetamide. As shown in [16, 18], thus one
prevents side reactions between the dichloride and the
solvent. The stirrer speed in the range studied (1000
15000 rpm) has almost no yield effect. At the same
time, at higher stirrer speeds overheating and foaming
of the reaction mixture was observed, and, therefore,
further work was performed at a stirrer speed of
1000 rpm.
80 60 40 20 0 20 40 60 80
Acid dichloride Diamine
Excess, mol %
Fig. 2. Yield monomer ratio plots for oligoamides XV,
0
XXII, and XXIX. c
= const.
diamine
Yield, %
80
XV
60
40
XXII
XXIX
20
Polycondensation of diamines with acid dichlorides
in solution is usually complete in 1 h. But the reaction
time may range from several minute to several hours,
depending on conditions [16, 19, 20]. The conversion
increases with increasing monomer concentrations.
The highest yield is observed in a wide range of con-
centrations (0.2 1.0 M). The reduced yield at con-
centrations below 0.2 M is apparently explained by
increase in the relative concentration of admixtures
and the resulting acceleration of side reactions. The
reduced yield at monomer concentrations above 1.0 M
is explained by increased viscosity of the system. The
wider optimum concentration range for the system in
study compared with systems described in the litera-
ture is associated with better solubilities of the mono-
mers and oligomers in the solvent applied. The
highest yield of oligoamides is at monomer concentra-
tions of 0.5 M (95%), but in further experiments we
used monomer concentrations of 0.2 M, providing an
almost the same yield (93%).
0.05
0
0.05 0.10 0.15 0.20
c0NaOH, M
c0HCl, M
Fig. 3. Yield pH plots for oligoamides XV, XXII, and
XXIX (c
perature 20 C).
0
0
= c
0.05 M, reaction tem-
acid dichloride
diamine
Phase-transfer polycondensation of diamines with
dicarboxylic acid chlorides is most commonly almost
insensitive to monomer ratio, since the rate of the
main reaction (polyamidation) is very high and
limited by diffusion of the reagents from bulk phases
to their interface, i.e. into the reaction zone [1].
The effect of monomer ratio on the synthesis of
oligoamides we studied by varying the initial con-
centration of acid chlorides at constant initial con-
centrations of diamines and HCl acceptor. The result-
ing experimental data are given in Table 2. Our data
are analogous to published data [1].
In view of the fact that the pH of the medium can
Experiments with 3,5-diamino-1,2,4-triazole and
differently affect condesation polyamidation processes, adipoyl and terephthaloyl chlorides showed that the
we studied the effect of acid base properties of the
medium of the yield and molecular weight of oligo-
amides. The pH of the aqueous phase was varied by
adding hydrochloric acid or sodium hydroxide. The
resulting data are represented in Fig. 3.
main reaction (polyamidation) is only slightly de-
celerated at lower temperatures in view of the higher
activity of terephthaloyl chloride and the higher
catalytic activity of the solvent (DMAA). Therewith,
side reactions are still more decelerated. The freezing
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001

ACYLATION OF AMINO-1,2,4-TRIAZOLES
561
point of DMAA is 20 C. Therefore, there is little
Yield, %
100
point in performing the reactions below this tempera-
ture because of the increased viscosity of the system.
Moreover, low temperatures are rather difficult to
maintain under conditions of exothermal reaction. In
view of the acceleration of side reactions, tempera-
tures above 30 C, too, are unsuitable. Figure 4 depicts
the temperature yield plots for oligoamides XV, XXII,
and XXIX.
XV
90
70
XXII
60
50
40
The fact that the yield of oligoamides decreases
with increasing temperature can be related to increas-
ing contribution of side reactions, primarily the reac-
tion of the dichlorides with DMAA. The range of
monomer concentrations suitable for synthesis of com-
pounds XV, XXII, and XXIX proved rather narrow
(0.5 0.1 M) because of the poor solubility of diamines
in DMAA.
XXIX
20 10 0 10 20 30 40 50 60
Temperature, %
Fig. 4. Yield initial temperature plots for oligoamides
XV, XXII, and XXIX.
Abundant evidence [15, 18] shows that the
maximum M and the maximum yield of polyamides
are attained at equimolar monomer ratios. As follows
from our results, this is also true of the system in
study. The corresponding experiments were performed
at 18 C with the concentration 0.2 M. The resulting
yield monomer ratio plot is given in Fig. 5.
Yield, %
100
80
60
40
XV
The unsymmetrical shape of the plots suggests that
hydrolysis of acid chlorides occurs at a higher rate
than salt formation by amino groups. Mention has
been made in the literature of the suppression the
hydrolysis in the presence of a small excess of acid
chloride. However, in our case this approach proved
ineffective.
XXII
20
XXIX
Thus, by examining the effect of reaction condi-
tions on the yield of oligoamides we found the follow-
ing optimal conditions of the synthesis: monomer
concentration 0.2 M, temperature 18 C, and equimolar
monomer ratio.
50
Diamine
25
0
25
50
Acid dichloride
Excess, mol %
Fig. 5. Yield monomer ratio plots for oligoamides XV,
XXII, and XXIX. c 0.2 M, reaction temperature 18 C.
The unsymmetrical shapes of the curves in Fig. 5
are apparently explained by the different nature of side
reactions that occur when one or the other monomer
is in excess. With excess acid dichloride, transacyla-
tion and transamination reactions involving the di-
chloride DMAA complex are much enhanced. With
excess diamine, no destructive reactions are initiated,
and the yield of polymers is reduced by no other
reason than disturbed equimolarity of the reagents.
Moreover, the excess of diamine is partly com-
pensated for by salt formation during the reaction
(diamine plays the role of HCl acceptor).
or Vaseline oils (solid samples) or thin films between
KBr plates (liquid samples). For measurements in the
1
4000 400 cm , KBr glasses were used. The 1H NMR
spectra were measured on a Bruker WP-80 spectro-
meter in DMSO-d6 (80 MHz, internal reference TMS).
Physicochemical properties of the oligomers and
details of their synthesis are listed in Tables 2 and 3.
N,N-Dimethylacetamide was kept for 24 h (with
intermittent shaking) over P2O5 and then distilled at
atmospheric pressure over fresh portions (50 g per 1 l)
of P2O5. For synthesis was used a fraction with bp
166 167 C (760 mm) (bp 165 C [4]). Moisture
content (by Fisher) 0.05%.
EXPERIMENTAL
The IR spectra (Table 1) were obtained on an IKS-
29 spectrophotometer for suspensions in fluorinated
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001

562
BARMIN et al.
1
Table 1. IR absorption bands of 1,2,4-triazole oligoamides (cm )
Comp.
no.
Stretching vibrations of
the triazole ring
Other
vibrations
(NH)
CO
I
2950 m, 2730 w, br 1663 s 1550 w, 1500 br, 1485 v.s, 1405 v.s,
2334 w, br 255 s
2335 w, br, 2985 w, br, 1665 s 1580 br, 1530 w, 1485 v.s, 1395 v.s, 2930 w [ (CH2)], 1470 br [ (CH2)]
III
2890 m, br, 2970 m, br
1275 br, 1350 s, 1270 m
VIII
X
2720 m, br
1660 s 1562 w, 1517 m, 1485 s, 1400 s, 1270 m 2860 w, 745 w
2963 w, 2360 m, br 1680 s 1575 w, 1505 m, 1480 v.s, 1400 s, 2932 m[ (CH2)], 2860 w, 1465 m
1290 v.s [ (CH2)], 745 w
1670 s 1610 s, 1565 s, 1545 br, 1490 br, 1480 v.s, 2930 m[ (CH2)], 2855 w, 1460 w
1425 m, 1385 m, 1350 s, 1300 br [ (CH2)], 733 w
XII
2960 w, 2880 br
XIV
XVI
XVIII
XX
2955 w, 2735 w, br 1665 s 1553 w, 1508 m, 1475 s, 1395 s, 1305 m 2935 w [ (CH2)], 2865 w, 1463 br
[ (CH2)], 737 w
2973 w, 2420 w
1650 s 1577 w, 1507 m, 1483 v.s, 1400 s, 2927 w [ (CH2)], 2863 w, 1470 m
1292 v.s [ (CH2)], 755 w
2830 w, 2465 m, br 1673 s 1607 m, 1560 m, br, 1487 br, 1480 v.s 2940 m[ (CH2)], 2865 w, 1465 m
1385 m, 1375 v.s, 1295 w, 1292 v.s [ (CH2)], 747 m
2885 w, 2385 w
1680 s 1575 w, 1523 w, 1485 v.s, 1400 br, 3127 w [ (CH2)], 1165 m, br
1395 m, 1270 m [ (CH2)]
1670 s 1590 m, 1553 m, 1522 w, 1485 v.s., 3123 w [ (CH2)], 2942 m[ (CH2)],
XXII
2900 w, 2405 w
1410 m, 1390 s, 1303 br, 1260 m
2865 w, 1463 m[ (CH2)], 1168 w
[ (CH2)], 737 w
XXIX
XXXI
2960 w, 2358 w, br 1645 s 1565 w, 1505 br, 1485 v.s, 1395 v.s, 1120 m, 1030 w, 990 w [ (C6H4)]
1272 w
2940 w, br, 2370 w, br 1660 s 1610 w, 1580 br, 1530 w, 1520 w, 1122 m, 1035 m, br, 993 w
1485 v.s, 1430 m, 1395 v.s, 1350 s, [ (C6H4)]
1275 m, 1270 m
XXXIII 2455 w, br
1608 m, 1602 br, 1560 m, 1483 s, 1437 m, 1130 w, 1020 w, 985 w, br
1385 s, 1352 w, 1305 br, 1268 w [ (C6H4)]
Table 2. Physicochemical properties and elemental analyses of oligoamides
Method
of syn-
thesisa
Found, %
H
Elementary
unit
formula
Calculation, %
b
c
Comp.
no.
,
,
TVDO,
sp
M
dl/g
kg/m3
C
C
N
C
H
N
I
III
X
G
G
PT
S
PT
S
PT
PT
PT
0.04
0.04
0.04
0.04
0.03
0.05
0.06
0.04
0.02
1395
1422
1480
1421
1361
1405
1370
230
255
290
280
265
270
255
250
275
30.4
31.8
2.3
2.2
43.8
49.4
C4H2N4O2
C6H5N9O2
31.4
32.7
2.0
1.8
45.7
50.9
1020
970
XVI
50.1
6.4
32.2
C12H19N5O2
50.6
6.1
33.7
1260
1880
XX
53.6
57.7
37.5
7.5
8.5
2.8
25.2
24.0
44.1
C17H24N8O2
C10HN4O9
C16H15N7O2
54.3
59.4
39.0
7.2
8.2
2.5
26.4
25.2
45.5
XXIX
XXXIII
1511
a
b
c
Here and in Table 3: (G) gas-phase, (PT) phase-transfer, and (S) solution. Specific viscosity. Vigorous decomposition onset point.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001

ACYLATION OF AMINO-1,2,4-TRIAZOLES
563
N,N-Dimethylacetamide + LiCl was supplied by
VNIIV Proekt (St. Peterburg). Moisture content (by
Fisher) 0.10 %.
Bis-3,3 -(5-amino-1,2,4-triazolyl) [22] was pre-
pared by base cyclization of oxalylaminoguanidine
synthesized by refluxing aminoguanidine hydrochlo-
ride and oxalic acid in water. For purification the re-
action products were dissolved in conc. H2SO4 and
reprecipitated from a fivefold volume of ice water.
The precipitate was filtered off, and the procedure was
repeated. After that the product was reprecipitated
from 15% aqueous alkali by addition of 5% HCl to
neutral reaction. The product was thoroughly washed
with distilled water and acetone, and dried at 80 90 C
(1 mm) for 24 h. Colorless powder.
5-Amino-1,2,4-triazole was prepared by the pro-
cedure in [21] by thermal cyclization of formylamino-
guanidine formed by heating a mixture of amino-
guanidine bicarbonate and aminoformic acid. Purifica-
tion was performed by triple crystallization from
absolute ethanol, followed by drying at 80 C (1 mm)
for 24 h. Colorless powder.
3,5-Diamino-1,2,4-triazole was synthesized by the
procedure in [18] from dicyandiamide and hydrazine
hydrate. For purification the product was doubly
crystallized from 95% ethanol and dried at 80 C
(1 mm) for 24 h. Colorless crystals. Analytical
characteristics of the sample were consistent with
published data [18].
Bis-3,3 -(5-amino-1,2,4-triazolyl)methane
was
synthesized from aminoguanidine hydrochloride and
malonic acid [22]. After triple crystallization from
water (with charcoal) is was dried at 80 90 C for
24 h. Colorless powder.
Table 3. Conditions of synthesis of 1,2,4-triazole oligoamides I XXXV
Quantity of monomers, g (mol)
Reaction
tempera-
ture,
Stirring
speed,
rpm
Reaction
time,
rpm
Comp.
no.
Reaction
medium
Acceptor of
HCl (mol)
Yield,
%
Method
diamine
acid chloride
C
I
II
G
G
G
G
G
G
S
Water
14.87 (0.15)
4.98 (0.03)
5.41 (0.03)
6.67
8.35 (0.03)
5.77 (0.03)
5.05 (0.06)
5.95 (0.06)
19.04 (0.15)
3.81 (0.03)
3.81 (0.03)
3.81
3.81 (0.03)
3.81 (0.03)
10.98 (0.06)
10.98 (0.06)
NaOH (0.30)
NaOH (0.60)
NaOH
NaOH
NaOH (0.60)
NaOH (0.60)
98 1
98 1
98 1
98 1
98 1
98 1
20
10 11
3 4
3 4
3 4
3 4
3 4
30
52
31
23
20
21
15
65
73
III
IV
V
VI
VII
VIII
DMAA
DMAA +
LiCl
2000
2000
S
20
30
IX
PT
Water
2.97 (0.03)
7.32 (0.04)
NaOH (0.04) 10000
20
5
70
hexane
X
XI
PT
S
1.66 (0.01)
5.41 (0.03)
2.01 (0.011) NaOH (0.11)
5.49 (0.03)
7000
2000
20
20
5
30
65
75
DMAA +
LiCl
XII
PT
S
Water
1.80 (0.01)
6.67 (0.03)
2.22 (0.01)
8.35 (0.03)
2.78 (0.01)
2.01 (0.011) NaOH
5.49 (0.03)
7000
2000
2000
2000
7000
20
20
20
30
20
5
30
5
72
71
69
74
72
hexane
DMAA +
LiCl
XIII
XIV
XV
PT
S
Water
2.01 (0.011) NaOH (0.11)
5.49 (0.03)
hexane
DMAA +
LiCl
30
5
XVI
PT
Water
2.01 (0.011) NaOH (0.11)
hexane
XVII
XVIII
XIX
PT
S
S
1.92 (0.01)
5.05 (0.06)
5.95 (0.06)
2.01 (0.011) NaOH (0.11)
14.35 (0.06)
14.35 (0.06)
7000
2000
2000
20
20
20
5
30
30
61
73
75
DMAA
DMAA +
LiCl
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001

564
BARMIN et al.
Table 3. (Contd.)
Quntity of monomers, g (mol)
Reaction
tempera-
ture,
Stirring
speed,
rpm
Reaction
time,
rpm
Comp.
Method
no.
Reaction
medium
Acceptor of
HCl (mol)
Yield,
%
diamine
acid chloride
2.39 (0.01)
C
XX
PT
Water
0.99 (0.01)
NaOH (0.10) 10000
20
5
71
hexane
XXI
XXII
PT
S
1.66 (0.01)
5.41 (0.03)
2.39 (0.01)
7.17 (0.03)
NaOH (0.10) 10000
2000
20
30
5
30
68
77
DMAA +
LiCl
XXIII
XXIV
XXV
PT
S
Water
1.80 (0.01)
6.67 (0.03)
2.78 (0.01)
2.39 (0.01)
7.17 (0.03)
2.39 (0.01)
NaOH (0.10)
7000
2000
7000
20
30
20
5
30
5
76
77
78
hexane
DMAA +
LiCl
Water
hexane
PT
NaOH (0.10)
NaOH (0.10)
XXVI
XXVII
PT
S
1.92 (0.01)
5.95 (0.06)
2.39 (0.01)
9.30 (0.06)
7000
2000
20
5 10
5
30
71
76
DMAA +
LiCl
XXVIII
XXIX
S
DMAA +
LiCl
Water
5.95 (0.06)
0.99 (0.01)
9.30 (0.06)
1.55 (0.01)
2000
7000
20
20
30
5
72
72
PT
NaOH (0.10)
NaOH (0.10)
hexane
XXX
XXXI
PT
S
1.66 (0.01)
5.41 (0.03)
1.55 (0.01)
4.65 (0.03)
7000
2000
20
30
5
30
60
72
DMAA +
LiCl
XXXII
PT
Water
hexane
1.80 (0.01)
1.55 (0.01)
NaOH (0.10)
NaOH (0.10)
7000
20
5
70
XXXIII
XXXIV
PT
S
2.22 (0.01)
8.35 (0.03)
1.55 (0.01)
4.65 (0.03)
7000
2000
20
30
5
30
70
74
DMAA +
LiCl
XXXV
PT
Water
1.92 (0.01)
1.55 (0.01)
NaOH
7000
20
5
68
hexane
1,7-Bis(5-amino-1,2,4-triazol-3-yl)octane [22]
was obtained from aminoguanidine hydrochloride and
sebacic acid. Purification was performed by triple
crystallization from boiling water, followed by wash-
ing with water and acetone, and 24-h drying at 80 C
(1 mm). Colorless crystals. All analytical characteris-
tics of the sample are close to thos reported in [22].
pressure, collecting a fraction with bp 61.0 61.1 C
(735 mm) (bp 61 C [25]). Yield 10 12%.
Adipoyl chloride. A commercial reagent of pure
grade was purified by triple vacuum distillation, col-
lecting a fraction with bp 100 101 C (2 mm) {bp
126 C (12 mm) [26]}. Yield 15 20%. The distillation
should be rapid and in small portions (50 ml) to avoid
strong tarring.
5-Amino-1H-1,2,3,4-tetrazole was obtained as
described in [23]. Colorless crystals. After crystalliza-
tion from water (1:4) and drying in air the yield was
121 g (65%), mp 205.5 206.5 C (mp 206.5 207.5 C
[22]).
Sebacoyl chloride. A commercial reagent of che-
mically pure grade was purified by triple distillation
at reduced pressure collecting a fraction with bp 150
152 C (3 4 mm) {bp 142 C (2 mm) [27]}.
Oxalyl chloride was synthesized by the Staudinger
method [24] by treatment of excess phosphorus penta-
chloride with anhydrous oxalic acid. Purification was
performed by quintuple distillation at atmospheric
Fumaroyl chloride was prepared by refluxing
fumaric acid in excess thionyl chloride [28] and
purified by distillation on a packed column 15 cm in
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001

ACYLATION OF AMINO-1,2,4-TRIAZOLES
565
height, collecting a fraction with bp 58 58.4 C
(36 mm) {bp 59 C (16 mm) [25]}.
meter) was continued for 30 min, during which time
the reaction mixture turned a brightly colored solution.
The resulting oligoamides were isolated in two ways.
Terephthaloyl chloride. A commercial reagent of
pure grade was recrystallized from dry hexane and
distilled at reduced pressure, collecting a fraction with
bp 112 114 C (5 mm). The resulting sample melted
at 83 84 C (mp 83 84 C [25]).
a. The reaction mixture was slowly poured with
vigorous stirring into 1 l of cold water. Stirring was
continued for 10 15 min, and the resulting oligoamide
that precipitated as flakes was separated by centrifug-
ing on an MP-2 centrifuge. The centrifugation time
was 3 5 min at 5000 rpm.
The purified acid chlorides were sealed in ampules
and stored in the dark. Terephthaloyl chloride was
stored in tightly stopped polyethylene beakers in a
vacuum dessicator. Adipoyl chloride and fumaroyl
b. The reaction mixture was slowly poured with
vigorous stirring into 300 ml of dry acetone. Stirring
chloride were unstable and tarred on storing; therefore, was continued for 10 15 min. The precipitate that
they were purified immediately before use. The other
acid chlorides could be stored under the above condi-
tions for some months.
formed was filtered off and treated with dry acetone
in a Soxhlet apparatus for 3 4 h to remove the starting
monomers and other admixtures. The oligomer was
filtered off, washed with dry acetone, and vacuum-
dried at 80 C (1 2 mm) for 12 h.
Phase-transfer polycondensation in a gas liquid
system. Diamine, 0.03 mol, and 0.06 mol of sodium
hydroxide were dissolved in 100 ml of water. The
resulting solution was heated in a beaker equipped
with a temperature-control unit and placed in a salt
bath to a specified temperature (usually 90 1 C), a
thin-wall evaporator with 0.03 mol of oxalyl chloride
was placed into the beaker. Oxalyl chloride vapors
was barboted by means of a gas-outlet tube through
the solution for 3 4 min, after which heating was
discontinued, and the reaction mixture was allowed to
cool to room temperature. The resulting oligoamide
that precipitated as colored flakes was filtered off and
washed with water (to remove Cl ions) and acetone.
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 4 2001