Synthesis of N-(oxyran-2-ylmethyl)triazoles and -tetrazoles

Article abstract of DOI:10.1134/S1070428015090171

The alkylation of 5-phenyl-1H-tetrazole and 4-nitro-2H-1,2,3-triazole with 1-chloro-2,3-epoxypropane and cycloaddition of 1-azido-3-chloropropan-2-ol to acetylenic dipolarophiles gave the corresponding N-(3-chloro-2-hydroxypropyl)azoles as intermediate pr

Full text of DOI:10.1134/S1070428015090171

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2015, Vol. 51, No. 9, pp. 1308–1312. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © T.V. Golobokova, A.G. Proidakov, L.I. Vereshchagin, V.N. Kizhnyaev, 2015, published in Zhurnal Organicheskoi Khimii, 2015,
Vol. 51, No. 9, pp. 1333–1337.
Synthesis of N-(Oxyran-2-ylmethyl)triazoles and -tetrazoles
T. V. Golobokova, A. G. Proidakov, L. I. Vereshchagin, and V. N. Kizhnyaev
Irkutsk State University, ul. Karla Marksa 1, Irkutsk, 664003 Russia
e-mail: kizhnyaev@chem.isu.ru
Received April 27, 2015
Abstract—The alkylation of 5-phenyl-1H-tetrazole and 4-nitro-2H-1,2,3-triazole with 1-chloro-2,3-epoxy-
propane and cycloaddition of 1-azido-3-chloropropan-2-ol to acetylenic dipolarophiles gave the corresponding
N-(3-chloro-2-hydroxypropyl)azoles as intermediate products in the synthesis of N-(oxiran-2-ylmethyl)azoles.
DOI: 10.1134/S1070428015090171
There are fairly scarce published data on the
synthesis of azoles with epoxy-containing substituents.
This is related primarily to difficulties arising from the
high reactivity of epoxy compounds and hence numer-
ous side reactions. In this work we propose several
ways of construction of an oxirane ring at an azole
cycle with a view to obtaining new mono- and poly-
functional azole-containing monomers which could
give rise to new high molecular weight compounds, as
well as to interesting and practically important mate-
rials based thereon.
presence of potassium hydroxide was also unsuccess-
ful. Probably, under these conditions initially formed
chlorohydrin 3a undergoes dehydrochlorination to
azole 4 which then polymerizes by the action of
5-phenyl-1H-tetrazole or KOH. No success was
achieved in attempted alkylation of tetrazole and such
bis-azoles as 5-[2-(tetrazol-5-yl)ethyl]- and 5-[2-(tetra-
zol-5-yl)butyl]tetrazoles with epichlorohydrin under
various conditions (in the presence of triethylamine or
NaOH as bases using acetone or DMF as solvent). In
all cases, tarry compounds were formed which we
failed to identify.
The alkylation of 5-phenyltetrazole with 1-chloro-
2,3-epoxypropane in acetone in the presence of tri-
ethylamine, followed by dehydrochlorination of inter-
mediate chlorohydrin was reported [1] to afford 1-(ox-
iran-2-ylmethyl)-5-phenyl-1H-tetrazole. We tried to
reproduce this procedure, but the desired tetrazole 4
was isolated in a poor yield, presumably because of
side reaction of intermediate chlorohydrin 3a with
initial 5-phenyl-1H-tetrazole (1a) to give 1,3-bis(5-
phenyl-1H-tetrazol-1-yl)propan-2-ol (5) (Scheme 1).
The alkylation of 1a with 2 in acetone–DMF in the
The optimal conditions for the alkylation of NH-
azoles with 2 include prolonged (8–12 h) heating of
equimolar amounts of the reactants in a polar aprotic
solvent in the absence of a catalyst. In this way, we
succeeded in synthesizing and identifying not only
oxirane-containing tetrazoles 4a and 4b (Scheme 1)
but also 4-nitro-2-(oxiran-2-ylmethyl)-2H-1,2,3-tri-
azole (8) (Scheme 2). The latter attracts interest due
to particular prospects in using nitro derivatives of
1,2,3-triazoles in various fields of practice [2–5].
Scheme 1.
Ph
O
N
N
N
N
R
R
HO
O
4
N
N
Cl
+
Cl
R = Ph
N
NH
N
N
Ph
Ph
N
N
N
N
OH
1a
N
N
1a–1c
2
3a–3c
N
N
N
N
5
R = Ph (a), MeOC(O)CH2 (b), NCCH2 (c).
1308

SYNTHESIS OF N-(OXYRAN-2-YLMETHYL)TRIAZOLES AND -TETRAZOLES
1309
Scheme 2.
HO
O
N
N
N
Cl
2, DMF, ∆
NaOH
NH
N
N
O2N
O2N
O2N
N
N
N
6
7
8
Scheme 3.
MeO
N
MeONa
+
Na+
N
O2N
HCl
N
N
O2N
NO2
O2N
N
N
O2N
HCl
NO2
N
Mg(OMe)2
Mg2+
6
N
O2N
N
2
9
Initial 4-nitro-2H-1,2,3-triazole (6) was prepared by
modified procedure [6]. The last step of this procedure,
alcoholysis of 2-(2,4-dinitrophenyl)-4-nitro-2H-1,2,3-
triazole implies intermediate isolation of 4-nitro-1,2,3-
triazole sodium salt which turned out to be sensitive to
temperature, and in some cases it ignited spontane-
ously on drying on a steam bath. We have found that
the isolation of nitrotriazole as magnesium salt 9
(Scheme 3) is more safe. According to the thermo-
gravimetric data, the ignition temperature of 9 is about
280°C, and the salt is isolated as crystal hydrate
containing five water molecules. The yield of 9 in this
step was 60%, and the overall yield of 6 calculated on
the initial phenylhydrazine was 25–30%.
the resulting chlorohydrins 12a–12c (Scheme 4). The
cycloaddition of azide 10 to unsymmetrical acetylenes
could give two regioisomeric triazoles. In the reaction
of 10 with phenylacetylene (11a) we isolated only one
isomer with the phenyl group attached to C4, as
followed from the position of the 5-H signal in the
1H NMR spectrum.
Initial 1-azido-3-chloropropan-2-ol (10) was syn-
thesized by reaction of epichlorohydrin (2) with
triethylammonium azide. It is advisable to perform the
reaction in diethyl ether without preliminary isolation
of the salt Et3N·HN3 which is highly hygroscopic and
unstable.
The structure of the isolated compounds was con-
firmed by NMR and IR spectra and elemental anal-
A synthetic route to N-glycidyl-substituted 1,2,3-tri-
azoles via cycloaddition of 1-azido-2,3-epoxypropane
to acetylenic compounds was considered in [7]. How-
ever, high reactivity of oxirane ring promoted various
side processes in the direct 1,3-dipolar cycloaddition of
1-azido-2,3-epoxypropane to acetylenic dipolarophiles,
which resulted in reduced yield of the target epoxy-
propyl-1,2,3-triazoles.
1
yses. The H NMR spectra of 3a–3c, 7, and 12a–12c
contained signals from protons in the chlorohydrin
fragment at δ 4.70–4.94, 3.71–3.89, and 4.17–
4.55 ppm, while epoxy derivatives 4, 8, and 13 dis-
played signals at δ 2.36–2.95 and 3.55–3.76 ppm due
to protons in the oxirane ring and at δ 4.65–4.90 ppm
due to “bridging” methylene group. In the IR spectra
of 3a–3c, 7, and 12a–12c we observed absorption
bands typical of O–H and C–Cl stretching vibrations in
the regions 3198–3364 and 719–783 cm–1, respec-
tively. The oxirane ring in 4, 8, and 13 was charac-
We have found that a rational method of synthesis
of triazoles 13 involves initial “classical” cycloaddition
of 1-azido-3-chloropropan-2-ol (10) to acetylenic com-
pounds 11a–11c, followed by dehydrochlorination of
Scheme 4.
R
R'
R
R'
Ph
HO
OH
Et3N·HN3
11a–11c
Cl
2
O
N3
Cl
R = Ph, R' = H
N
N
N
N
N
N
10
12a–12c
13
R = Ph, R′ = H (a); R = R′ = HOC(O) (b); R = HOCPh2, R′ = H (c).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

GOLOBOKOVA et al.
1310
terized by IR absorption bands at 1249–1261 and 829–
875 cm , while neither O–H nor C–Cl bands were
present in the IR spectra of these compounds.
lar way. Yield 1.8 g (54%), viscous liquid. IR spec-
trum, ν, cm–1: 3364 (O–H), 1737 (C=O), 771 (C–Cl).
Found, %: C 36.12; H 4.61; N 24.71. C7H11ClN4O3.
Calculated, %: C 35.83; H 4.73; N 23.88.
−
1
The isomeric products were identified, and their
1
2-[1-(3-Chloro-2-hydroxypropyl)-1H-tetrazol-5-
yl]acetonitrile (3c) was synthesized in a similar way
from 0.7 g (6 mmol) of tetrazole 1c and 0.6 g (6 mmol)
of 2 in 10 mL of DMF. Yield 0.6 g (55%), viscous
liquid. IR spectrum, ν, cm–1: 3344 (O–H), 2263 (C≡N),
ratios were determined, on the basis of the H NMR
spectra from the positions and intensities of the 5-H
signal in nitrotriazole derivatives and o-H in 5-phenyl-
tetrazoles. It is known [8, 9] that the signals from the
above protons in the spectra of 1-R-4-nitrotriazoles
and 1-R-5-phenyltetrazoles are located in a weaker
field than those of 2-R-isomers. In the spectra of tetra-
zoles 3a and 4 we observed two o-H signals at δ 8.09–
8.16 and 7.68–7.76 ppm; their intensity ratio indicated
predominant formation of the N1-substituted isomer
(~95%). 4-Nitrotriazole derivatives 7 and 8 displayed
5-H signal at δ 8.46 ppm and were identified as
N2-isomers (92%). In addition, small amounts (8%) of
1-substituted 5-nitro-1,2,3-triazoles (δ4-H 8.64 ppm)
were detected.
1
756 (C–Cl). H NMR spectrum, δ, ppm: 3.77 d.d (1H,
2
3
CH2Cl, J = 11.8, J = 7.5 Hz), 3.97 d.d (1H, CH2Cl,
2J = 11.8, J = 2.8 Hz), 4.23 (1H, CH), 4.42 s (2H,
CH2CN), 4.58 d.d (1H, CH2, J = 13.3, J = 7.8 Hz),
4.78 d.d (1H, CH2, J = 13.2, J = 5.1 Hz), 7.37 br.s
(1H, OH). Found, %: C 36.31; H 4.95; N 32.98.
C6H8ClN5O. Calculated, %: C 35.74; H 4.00; N 34.74.
3
2
3
2
3
1-(Oxiran-2-ylmethyl)-5-phenyl-1H-tetrazole (4).
A solution of 0.5 g (12.5 mmol) of sodium hydroxide
in 5 mL of water was added in portions to a solution of
2 g (8 mmol) of compound 3a in 15 mL of acetone,
and the mixture was stirred for 1 h at 25°C. The pre-
cipitate (NaCl) was filtered off, the filtrate was diluted
with 10 mL of water and extracted with diethyl ether,
and the extract was dried over CaCl2 and evaporated in
air. Yield 1.4 g (88%), mp 46–48°C (from EtOAc) [1].
EXPERIMENTAL
The IR spectra were recorded on an Infralum FT-
801 spectrometer from samples prepared as KBr discs
1
or Nujol mulls. The H NMR spectra were measured
1
IR spectrum, ν, cm–1: 875, 1250 (oxirane). H NMR
on a Varian VXR-500s instrument (500 MHz) from
solutions in acetone-d6 or CDCl3. The elemental anal-
yses were obtained on a Flash EA 1112 Series CHN
analyzer. The progress of reactions was monitored by
TLC on Silufol plates using ethyl acetate–hexane (2:3)
as eluent. Thermogravimetric analysis was performed
on a Perkin Elmer SII Diamond TG/DTA instrument
(dynamic mode, heating rate 5 deg/min).
2
3
spectrum, δ, ppm: 2.26 d.d (1H, 3′-H, J = 6.3, J =
3.4 Hz), 2.46 d.d (1H, 3′-H, 2J = 6.3, 3J = 4.1 Hz), 3.55
2
(1H, 2′-H), 4.31 d.d (1H, CH2, J = 13.2, 3J = 3.2 Hz),
4.55 d.d (1H, CH2, 2J = 13.2, 3J = 6.6 Hz), 7.49 m (3H,
m-H, p-H), 7.68 m (2H, o-H, N2 isomer), 8.16 m (2H,
o-H, N1-isomer).
1,3-Bis(5-phenyl-1H-tetrazol-1-yl)propan-2-ol
(5). A mixture of 5.3 g (36 mmol) of 5-phenyltetrazole,
1.5 g (36 mmol) of sodium hydroxide or 3.6 g
(36 mmol) of triethylamine, and 3.3 g (36 mmol) of
epichlorohydrin (2) in 20 mL of ethanol was stirred for
4 h at 20–25°C. The precipitate was filtered off. Yield
7.4 g (59%), mp 198°C (from EtOH) [1]. IR spectrum:
1-Chloro-3-(5-phenyl-1H-tetrazol-1-yl)propan-2-
ol (3a). A solution of 2 g (0.014 mol) of 5-phenyl-
tetrazole (1a) and 1.3 g (0.014 mol) of epichlorohydrin
(2) in 15 mL of DMF was stirred for 8 h at 80°C, and
the solvent was removed under reduced pressure. Yield
1.5 g (45%), mp 84–86°C (from EtOH). IR spectrum,
1
ν 3362 cm–1 (O–H). H NMR spectrum, δ, ppm:
1
ν, cm–1: 3240 (O–H), 780 (C–Cl). H NMR spectrum,
2
3
2
3.92 d.d (4H, CH2, J = 11.8, J = 6.7 Hz), 5.50 t (1H,
δ, ppm: 3.54 br.s (1H, OH), 3.61 d.d (1H, CH2Cl, J =
3
11.8, 3J = 7.5 Hz), 3.81 d.d (1H, CH2Cl, 2J = 11.8, 3J =
CH, J = 6.7 Hz), 7.55–7.91 m (10H, Harom), 13.54 s
2
(1H, OH).
2.8 Hz), 4.55 m (1H, CH), 4.77 d.d (1H, CH2, J =
3
2
3
13.2, J = 5.0 Hz), 4.77 d.d (1H, CH2, J = 13.2, J =
7.0 Hz), 7.49 m (3H, m-H, p-H), 7.76 m (2H, o-H,
N2-isomer), 8.09 m (2H, o-H, N1-isomer). Found, %:
C 50.02; H 4.69; N 23.51. C10H11ClN4O. Calculated,
%: C 50.32; H 4.65; N 23.47.
4-Nitro-1,2,3-triazole (6). Magnesium salt 9, 10 g
(0.04 mol), was dispersed in 15 mL of water, concen-
trated aqueous HCl was added to pH 2, and the precip-
itate was filtered off. Yield 8.5 g (93%), mp 158°C
(from EtOAc) [6].
Methyl 2-[1-(3-chloro-2-hydroxypropyl)-1H-
tetrazol-5-yl]acetate (3b) was synthesized in a simi-
1-Chloro-3-(4-nitro-2H-1,2,3-triazol-2-yl)pro-
pan-2-ol (7) was synthesized as described above for
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

SYNTHESIS OF N-(OXYRAN-2-YLMETHYL)TRIAZOLES AND -TETRAZOLES
1311
3a–3c from 2 g (18 mmol) of 6 and 1.7 g (18 mmol) of
2 in 15 mL of DMF. Yield 0.4 g (11%), mp 104–105°C
(from EtOAc). IR spectrum, ν, cm-1: 3380 (O–H), 783
IR spectrum, ν, cm–1: 3196 (O–H), 3139 (C–H), 719
1
(C–Cl). H NMR spectrum, δ, ppm: 3.55 d.d (1H,
2
3
CH2Cl, J = 11.8, J = 7.5 Hz), 3.75 d.d (1H, CH2Cl,
1
2J = 11.8, 3J = 2.8 Hz), 4.20 m (1H, CH), 4.64 d.d (1H,
CH2, J = 13.2, J = 7.5 Hz), 4.80 d.d (1H, CH2, J =
13.2, J = 2.8 Hz), 7.37 br.s (1H, OH), 7.55–7.68 m
(C–Cl). H NMR spectrum, δ, ppm: 4.17 d.d (1H,
2
3
2
3
2
CH2Cl, J = 11.8, J = 7.5 Hz), 4.23 d.d (1H, CH2Cl,
2J = 11.8, J = 2.8 Hz), 4.17 m (1H, CH), 4.84 d.d
3
3
2
3
(1H, CH2, J = 11.8, J = 7.7 Hz), 5.15 d.d (1H, CH2,
(5H, Harom), 8.20 s (1H, 5-H). Found, %: C 54.70;
H 5.10; N 18.09. C11H12ClN3O. Calculated, %:
C 55.59; H 5.09; N 17.68.
2J = 11.8, J = 5.1 Hz), 7.41 br.s (1H, OH), 7.96 s
3
(1H, 5-H). Found, %: C 29.04; H 3.38; N 27.25.
C5H7ClN4O3. Calculated, %: C 29.07; H 3.42; N 27.12.
1-(3-Chloro-2-hydroxypropyl)-1H-1,2,3-triazole-
4,5-dicarboxylic acid (12b) was synthesized in a simi-
lar way from 2 g (17 mmol) of acetylenedicarboxylic
acid (11b) and 2.7 g (20 mmol) of azide 10 in 25 mL
of ethanol. Yield 3.1 g (73%), mp 105–106°C
(decomp., from EtOAc). IR spectrum, ν, cm–1: 3267
(O–H), 768 (C–Cl). Found, %: C 34.13; H 3.72;
N 15.06. C7H8ClN3O5. Calculated, %: C 33.68; H 3.23;
N 16.83.
4-Nitro-2-(oxiran-2-ylmethyl)-2H-1,2,3-triazole
(8) was synthesized as described above for compound
4 from 0.1 g (0.4 mmol) of 7 using 0.024 g (0.6 mmol)
of NaOH. Yield 0.06 g (86%), mp 132°C (from
EtOAc). IR spectrum, ν, cm–1: 832, 1249 (oxirane).
2
1H NMR spectrum, δ, ppm: 2.77 d.d (1H, 3′-H, J =
3
2
3
6.3, J = 3.2 Hz), 2.90 d.d (1H, 3′-H, J = 6.3, J =
4.1 Hz), 3.54 (1H, 2′-H), 4.70 d.d (1H, CH2, 2J = 13.2,
3J = 3.2 Hz), 5.00 d.d (1H, CH2, J = 13.3, J =
3.2 Hz). Found, %: C 36.24; H 3.97; N 32.15.
C5H6N4O3. Calculated, %: C 35.30; H 3.55; N 32.93.
2
3
1-Chloro-3-{4-[hydroxy(diphenyl)methyl]-1H-
1,2,3-triazol-1-yl}propan-2-ol (12c) was synthesized
in a similar way from 0.5 g (4 mmol) of azide 10 and
0.9 g (4 mmol) of acetylenic alcohol 11c in 10 mL of
toluene. Yield 0.45 g (32%), mp 40–42°C (decomp.,
from EtOAc). IR spectrum, ν, cm–1: 3291, 3269
(O–H), 3087 (C–H), 757 (C–Cl). 1H NMR spectrum, δ,
4-Nitro-1,2,3-triazole magnesium salt (9). Mag-
nesium turnings, 2.4 g, were dissolved in 300 mL of
methanol on heating, the mixture was heated for
30 min under reflux and cooled to room temperature,
and 42 g (0.15 mol) of 4-nitro-2-(2,4-dinitrophenyl)-
2H-1,2,3-triazole was added. The mixture was heated
for 3 h under reflux, 220–225 mL of methanol was
distilled off, 400 mL of water was added to the residue
under stirring, and the mixture was cooled. The precip-
itate was filtered off and washed with water. The fil-
trate was combined with the washings and evaporated
on a steam bath, and the residue was recrystallized
from propan-2-ol. Yield 34 g (90%).
2
3
ppm: 3.97 d.d (1H, CH2Cl, J = 11.8, J = 7.5 Hz),
2
3
4.17 m (1H, CH), 4.63 d.d (1H, CH2, J = 13.3, J =
7.7 Hz), 4.77 d.d (1H, CH2Cl, J = 11.8, J = 2.8 Hz),
4.83 d.d (1H, CH2, J = 13.2, J = 2.8 Hz), 6.70 br.s
(1H, OH), 6.80 s (1H, 5-H), 7.17–7.44 m (10H, Harom).
Found, %: C 63.54; H 5.91; N 11.63. C18H18ClN3O2.
Calculated, %: C 62.88; H 5.28; N 12.22.
2
3
2
3
1-(Oxiran-2-ylmethyl)-4-phenyl-1H-1,2,3-tri-
azole (13) was synthesized as described above for 4
from 0.5 g (2.4 mmol) of 12a using 0.1 g (2.4 mmol)
of NaOH. Yield 0.38 g (96%), mp 80–82°C (from
EtOAc). IR spectrum, ν, cm–1: 829, 1261 (oxirane).
1-Azido-3-chloropropan-2-ol (10). A dry solution
of HN3 in diethyl ether, prepared from 30 g (0.46 mol)
of sodium azide and concentrated HCl, was cooled to
0°C, 23 g (0.23 mol) of triethylamine was added drop-
wise, 21 g (0.22 mol) of epichlorohydrin (2) was then
added, and the mixture was stirred for 8 h at 35°C.
When the reaction was complete, the mixture was
evaporated, and the residue was distilled under reduced
pressure. Yield 3.8 g (95%), bp 80–84°C (7 mm). IR
spectrum, ν, cm–1: 3258 (O–H), 2108 (N3), 719 (C–Cl).
2
1H NMR spectrum, δ, ppm: 2.26 d.d (1H, 3′-H, J =
3
2
3
6.3, J = 3.4 Hz), 2.46 d.d (1H, 3′-H, J = 6.3, J =
4.1 Hz), 3.75 (1H, 2′-H), 4.33 d.d (1H, CH2, 2J = 13.3,
3J = 3.2 Hz), 4.53 d.d (1H, CH2, J = 13.3, J =
6.6 Hz), 7.55–7.66 m (5H, Harom), 8.49 s (1H, 5-H).
Found, %: C 36.24; H 3.97; N 32.15. C5H6N4O3. Cal-
culated, %: C 35.30; H 3.55; N 32.93.
2
3
1-Chloro-3-(4-phenyl-1H-1,2,3-triazol-1-yl)pro-
pan-2-ol (12a). A solution of 3.2 g (0.024 mol) of
azide 10 and 2 g (0.02 mol) of phenylacetylene (11a)
in 25 mL of toluene was stirred for 12 h at 85–90°C,
and the solvent was removed under reduced pressure.
Yield 2.9 g (61%), mp 126–127°C (from EtOAc).
This study was performed under financial support
by the Ministry of Education and Science of the
Russian Federation (base part of state assignment in
the field of research activity, no. 2014/51; project
no. 01201461924).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015

GOLOBOKOVA et al.
soedinenii (Chemistry of Aliphatic and Alicyclic Nitro
1312
REFERENCES
Compounds), Moscow: Khimiya, 1974, p. 153.
5. Livi, O., Biagi, G., Ferretti, M., Lucacchini, A., and
1. Buzilova, S.R., Kuznetsova, N.I., Shul’gina, V.M.,
Gareev, G.A., and Vereshchagin, L.I., Chem. Heterocycl.
Compd., 1983, vol. 19, p. 107.
Berili, L., Eur. J. Med. Chem., 1983, vol. 18, p. 171.
6. Eages, T., Khan, M.A., and Lynch, B.M., Org. Prep.
Proced. Int., 1970, vol. 2, p. 117.
7. Maksikova, A.V., Serebryakova, E.S., Shcherbakov, V.V.,
Gareev, G.A., and Vereshchagin, L.I., Zh. Org. Khim.,
1989, vol. 25, p. 1519.
2. Licht, H.H. and Ritter, H., J. Energ. Mater., 1994,
vol. 12, p. 223.
3. Kagitani, T., Minagawa, M., Nakakata, Y., Kimura, R.,
Tsubakimoto, T., Oshiumi, R., and Sakano, K., JPN
Patent no. 6239525, 1987; Chem. Abstr., 1987, vol. 107,
no. 59040.
8. Khan, M.A. and Lynch, B.M., J. Heterocycl. Chem.,
1970, vol. 7, p. 1237.
9. Vereshchagin, L.I., Kuznetsova, N.I., Kirillova, L.P.,
Shcherbakov, V.V., Sukhanov, G.T., and Gareev, G.A.,
Chem. Heterocycl. Compd., 1986, vol. 22, p. 745.
4. Novikov, S.S., Shveikhgeimer, G.A., and Sevost’yano-
va, V.A., Khimiya alifaticheskikh i alitsiklicheskikh nitro-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 9 2015