Synthesis of Tetrazoles from Amines Mediated by New Copper Nanocatalyst

Article abstract of DOI:10.1134/S1070428019100208

New copper nanocatalyst was prepared by coating Fe₃O₄ magnetic nanoparticles with tetraethyl orthosilicate (TEOS), followed by functionalization with 3-chloropropyl(trimethoxy)silane and 4H-1,2,4-tri-azol-4-amine and complexation with copper(II) chloride. The new catalyst was characterized by various spectroscopic methods and was successfully used in the synthesis of 1-aryl-1H-tetrazoles by reaction of aromatic amines with sodium azide and triethyl orthoformate under solvent-free conditions at 100°C.

Full text of DOI:10.1134/S1070428019100208

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2019, Vol. 55, No. 10, pp. 1591–1597. © Pleiades Publishing, Ltd., 2019.
Synthesis of Tetrazoles from Amines Mediated
by New Copper Nanocatalyst
M. Ariannezhada, D. Habibia,* and S. Heydaria
a Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran
*e-mail: davood.habibi@gmail.com
Received May 11, 2019; revised August 17, 2019; accepted August 18, 2019
Abstract—New copper nanocatalyst was prepared by coating Fe3O4 magnetic nanoparticles with tetraethyl
orthosilicate (TEOS), followed by functionalization with 3-chloropropyl(trimethoxy)silane and 4H-1,2,4-tri-
azol-4-amine and complexation with copper(II) chloride. The new catalyst was characterized by various
spectroscopic methods and was successfully used in the synthesis of 1-aryl-1H-tetrazoles by reaction of
aromatic amines with sodium azide and triethyl orthoformate under solvent-free conditions at 100°C.
Keywords: Fe3O4 magnetic nanoparticles, 4H-1,2,4-triazole-4-amine, copper complex, aromatic amines,
sodium azide, 1-aryl-1H-tetrazoles.
DOI: 10.1134/S1070428019100208
Tetrazole derivatives are used in biological and
pharmaceutical industries [1–15], and the chemistry of
tetrazoles has gained increasing attention since the
early 1980s [2]. Among heterogeneous catalysts used
for the synthesis of various tetrazoles, the application
of nanocatalysts has received considerable attention in
recent decades due to their unique surface and catalytic
properties [16, 17]. The surface area to volume ratio
increases with decrease in the radius of the sphere and
vice versa. Therefore, as particle size decreases,
a greater portion of atoms therein appear at the surface
compared to those inside the particle. Thus, nano-
particles have a much greater surface area per unit
volume compared with larger particles.
ous catalyst to be used for the one-pot three-com-
ponent synthesis of various tetrazoles [25, 26].
The results of our studies showed that 5-arylamino-
1H-tetrazole isomers can be obtained from arylcyan-
amides bearing an electron-withdrawing substituent on
the aryl ring and that the reaction direction changed
toward the formation of 1-aryl-5-amino-1H-tetrazole
isomer as the electron-donating power of the substit-
uent increased. We also found that the reactions with
arylcyanamides having electron-donating groups on
the aromatic ring were complete in a shorter time than
the reactions with those containing electron-withdraw-
ing substituents.
Now, we report a new heterogeneous copper
nanocatalyst which was prepared by coating Fe3O4
magnetic nanoparticles with tetraethyl orthosilicate
(Fe3O4/SiO2), followed by functionalization with
3-chloropropyl(trimethoxy)silane and 4H-1,2,4-triazol-
4-amine and complexation with copper(II) chloride.
The new catalyst was characterized and applied to the
synthesis of 1-aryl-1H-tetrazoles from various aro-
matic amines, sodium azide, and triethyl orthoformate
under solvent-free conditions at 100°C.
Reported syntheses of tetrazoles suffer from some
disadvantages, such as low yield, long reaction times,
harsh reaction conditions, low accessibility of starting
materials, use of expensive and toxic reagents, and in
situ generation of hydrazoic acid which is highly toxic
and explosive [18, 19]. We tried to develop useful
catalytic procedures that would have all possible
benefits and advantages of the former methods without
their disadvantages. For example, we reported the use
of ZnCl2 [20], FeCl3–SiO2 [21], natrolite zeolite [22],
ZnCl2/AlCl3/silica (ZAS) [23], and ZnO [24] for the
preparation of various tetrazole derivatives. Also,
Fe3O4 magnetic particles were functionalized with
1,10-phenanthroline-5,6-diol, and the corresponding
manganese complex was synthesized as a heterogene-
The new copper nanocatalyst was synthesized
according to Scheme 1 and was characterized by
inductively coupled plasma (ICP) analysis, FT-IR,
X-ray diffraction (XRD), energy dispersive X-ray
spectroscopy (EDX), scanning electron microscopy
(SEM), transmission electron microscopy (TEM),
1591

ARIANNEZHAD et al.
1592
Scheme 1.
Si(OEt)4, H2O/EtOH
NH3, room temp., 12 h
O
SiO2
SiO2
Cl(CH2)3Si(OMe)3
O
Fe3O4
Fe3O4
Fe3O4
Si
Cl
O
A
B
C
N
Cu2+
N
N
N
N
NH2
reflux, 12 h
CuCl2, EtOH
N
O
O
SiO2
SiO2
N
80°C, 8 h
N
N
O
O
O
Fe3O4
Fe3O4
Si
N
Si
N
H
H
O
D
E, copper nanocatalyst
thermogravimetric–differential thermal analysis
(TGA–DTA), and vibrating sample magnetometry
(VSM).
Figure 1 shows the FT-IR spectra of A–E. The
spectrum of A contains a basic characteristic peak at
about 579 cm–1 which is attributed to Fe–O stretching
vibrations. Curve B shows a broad band near
1086 cm–1 due to Si–O bonds. A new peak at 583 cm–1
in the spectrum of C indicates the presence of C–Cl
bonds. Curve D displays two new peaks at 1338 and
1650 cm–1 corresponding to the triazole C–N and C=N
bonds, respectively. Finally, the shift of the C=N band
to 1627 cm–1 in the spectrum of the new catalyst (E) is
related to copper coordination to the C=N nitrogen
atom. Thus, comparison of the IR spectra of A–E con-
firms successful preparation of the Cu nanocatalyst.
The ICP analysis of the catalyst showed the Cu
content of about 20.76%.
A
B
C
D
E
The XRD pattern (Fig. 2, curve 1) showed peaks at
2θ = 10, 30, 35, 45, 53, 57, 63, 74° which are consis-
tent with the silica-coated magnetite nanoparticle
structure. The new peaks at 2θ = 28, 40, 50, and
66° appeared in the X-ray powder pattern of E were
attributed to Cu species (Fig. 2, curve 4). The
chemical composition of the Cu nanocatalyst was
determined by EDX analysis (Fig. 3). The results
confirm the presence of the anticipated elements in the
structure of the catalyst, namely C, N, O, Si, Fe, and
Cu. The morphology and the particle size of the Cu
nanocatalyst were determined by SEM and TEM
techniques (Figs. 4, 5). According to the obtained
images, the nanocatalyst particle size is in the nano-
meter range (between 44.28 and 63.24 nm).
ν, cm–1
Fig. 1. FT-IR spectra of A, B, C, D, and E.
250
200
150
100
50
1
2
3
4
0
0
10
20
30
40
50
60
70
2θ, deg
Fig. 2. XRD patterns of (1) Fe3O4/SiO2 (B), (2) Fe3O4/SiO2/
CPTMS (C), (3) Fe3O4/SiO2/CPTMS/AT (D), and
(4) Fe3O4/SiO2/CPTMS/AT/Cu (E).
The thermogravimetric analysis curves of the
catalyst showed weight loss due to thermal decom-
position of the organic material (Fig. 6). The catalyst
showed about three weight loss steps in the tempera-
ture ranges of 140, 175, and 235°C, respectively. The
initial weight loss at 140°C is probably due to the
residual water, the second step at 175°C is attributed to
the thermal decomposition of the complex, and the
third step is probably due to thermal decomposition of
the aminotriazole and (propyl)silane moieties.
0
1
2
3
4
5
6
7
8 E, keV
Fig. 3. EDX analysis of the catalyst.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019

SYNTHESIS OF TETRAZOLES FROM AMINES
1593
Fig. 4. SEM images of the catalyst.
Fig. 5. TEM images of the catalyst.
Fig. 6. TGA–DTA patterns of the catalyst in a nitrogen atmosphere.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019

ARIANNEZHAD et al.
1594
A
B
C
D
E
Fig. 7. VSM analyses of A–E.
sponding 1-aryl-1H-tetrazoles were obtained with
good to excellent yields (Table 4).
The VSM analyses of A–E were performed in order
to demonstrate and compare their magnetic properties
(Fig. 7). As can be seen, all five compounds have
magnetic properties which decrease in going from A to
E (65, 35, 30, 5.15, and 3.65 emu/g, respectively). This
can be explained assuming probable reduction in
dipole–dipole interactions between magnetic nano-
particles after modification and complexation which
make them coated to a greater extent.
1-Aryl-1H-tetrazoles 2a–2j were reported previ-
ously. The products were identified by comparing their
physical and spectroscopic data with those given in the
literature. Their structures were in agreement with the
IR and NMR spectra. In the IR spectra of all products,
no sharp NH2 peak typical of initial anilines was
observed in the region 3300–3500 cm–1.
Scheme 3 outlines a plausible mechanism for the
formation of tetrazoles in the described reaction. Being
a Lewis acid, the catalyst is likely to add to the oxygen
atom of ethoxy group of HC(OEt)3, which facilitates
nucleophilic attack of the amino nitrogen atom on the
central carbon atom of the ortho ester. Next follow
successive elimination of two ethanol molecules,
nucleophilic attack of azide anion, and cyclization to
form the final product.
The new catalyst was tested in the synthesis of
1-aryl-1H-tetrazoles 2a–2j by reaction of aromatic
amines 1a–1j with sodium azide and triethyl ortho-
formate (Scheme 2). The reaction conditions were
optimized using the reaction of 4-nitroaniline with
sodium azide and HC(OEt)3 as model by varying the
catalyst amount, solvent, and temperature (Tables 1–
3). The best result was obtained using equimolar
amounts (2 mmol) of the reactants and 50 mg of cop-
per nanocatalyst at 100°C in the absence of a solvent.
The optimized conditions were then applied to the
reactions with other substituted anilines, and the corre-
The reusability of the Cu nanocatalyst was studied
in the model reaction. The catalyst was separated from
the reaction mixture by filtration after the first run,
Scheme 2.
Copper nanocatalyst
no solvent, 100°C
N
RNH2
+
CH(OEt)3
+
NaN3
N
N
R
N
1a–1j
2a–2j
R = Ph (a), 2,4-Me2C6H3 (b), 4-MeC6H4 (c), 4-MeOC6H4 (d), 4-MeC(O)C6H4 (e), 4-BrC6H4 (f), 2-ClC6H4 (g),
4-ClC6H4 (h), 4-O2NC6H4 (i), 3-F3CC6H4 (j).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019

SYNTHESIS OF TETRAZOLES FROM AMINES
Table 1. Effect of the catalyst amount on the yield of 2ia
1595
Scheme 3.
EtO
H
Catalyst, mg
Yield, %
R
H
R
NH2 +
N
H
–EtOH
EtO
EtO
Cu
OEt
10
20
30
40
50
Traces
35
OEt
N–
–N
N
N–
53
R
R
N
73
N
OEt
N
N
–EtOH
–EtOH
93
N
a
Reaction conditions: 1i, 2 mmol; NaN3, 2 mmol; HC(OEt)3,
2 mmol; no solvent, 100°C, 2 h.
N
R
N
N
Table 2. Effect of solvent on the yield of 2ia
washed with ethanol, dried under reduced pressure,
and reused for the next run under the same conditions.
The yields of tetrazole 2i in five successive runs were
93, 91, 88, 85, and 82%, respectively. Thus, the new
catalyst can be reused up to five times without
significant loss of activity.
Solvent
Yield, %
H2O
Traces
18
EtOH
DMF
74
In summary, we have prepared a new heterogene-
ous copper nanocatalyst from silica-coated Fe3O4
nanoparticles modified with 3-chloropropyl(trime-
thoxy)silane and 4H-1,2,4-triazol-4-amine and demon-
strated its high efficiency in the solvent-free synthesis
of 1-aryl-1H-tetrazoles from substituted anilines,
sodium azide, and triethyl orthoformate at 100°C.
Toluene
DMSO
None
42
61
93
a
Reaction conditions: 1i, 2 mmol; NaN3, 2 mmol; HC(OEt)3,
2 mmol; catalyst, 50 mg; solvent, 5 mL, 100°C, 2 h.
Table 3. Effect of temperature on the yield of 2ia
EXPERIMENTAL
Temperature, °C
Yield. %
18–25
040
21
42
71
93
The IR spectra were recorded on a Perkin–Elmer
GX Fourier transform infrared spectrometer. The
NMR spectra were recorded on a Jeol FT NMR 90
spectrometer. The TEM images were recorded on
a Zeiss-EM10C-80 KV transmission electron micro-
scope, and the SEM images were recorded on a Philips
XL-30 scanning electron microscope. The XRD
measurements were done with a Bruker D8 Advance
powder diffractometer (Cu Kα radiation, λ = 1.54 Å).
The size distributions were measured with a Malvern
Zetasizer Nano-ZS-90 (ZEN 3600) instrument. The
ICP measurements of the metal content were per-
formed using a Perkin Elmer ICP/6500 instrument.
Magnetic measurements were carried out at room tem-
perature using an Iranian Meghnatis Daghigh Kavir
Co. Vibrating Sample Magnetometer (VSM). Chemi-
cals and solvents were purchased from Merck and
Sigma-Aldrich and used without further purification.
080
100
a
Reaction conditions: 1i, 2 mmol; NaN3, 2 mmol; HC(OEt)3,
2 mmol; catalyst, 50 mg; no solvent, 2 h.
a value of 10. The mixture was heated for 0.5 h at
70°C, and the black magnetic solid (Fe3O4 magnetic
nanoparticles, A) was filtered off, washed with water,
and dried at 80°C for 12 h. A 0.2-g sample of Fe3O4
MNPs was dispersed in a mixture of ethanol and
distilled water (250 mL, 4:1 by volume) and aqueous
ammonia (3 mL) under ultrasonication. Tetraethyl
orthosilicate (2 mL) was then slowly added dropwise,
and the mixture was stirred for 6 h. The product (B)
was separated by centrifugation, washed with water
and ethanol for several times, and dried under reduced
pressure. 3-Chloropropyl(trimethoxy)silane (1.0 mL,
5 mmol) was dissolved in anhydrous toluene
(100 mL), Fe3O4/SiO2 (1.0 g) was added, and the mix-
ture was stirred for 18 h at 60°C. The resulting mag-
netic solid (C) was separated using a strong magnet,
washed with toluene, and dried under reduced pres-
Preparation of copper nanocatalyst. A mixture of
FeCl3·6H2O (11.44 g) and FeCl2·4H2O (4.3 g) was
dissolved in water (100 mL), and the solution was
stirred for 0.5 h at 80°C. A 37% aqueous ammonia
solution was then added dropwise with vigorous
stirring, and a black solid separated when pH reached
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019

ARIANNEZHAD et al.
1596
Table 4. Synthesis of tetrazoles 2a–2j
mp, °C
Reaction time,
Initial compd. no.
Product no.
Yield, %
min
found
reported
1a
1b
1c
1d
1e
1f
1g
1h
1i
2a
2b
2c
2d
2e
2f
2g
2h
2i
80
100
90
100
110
180
100
180
120
115
90
82
92
91
87
75
85
86
93
82
63–66
132–134
93–95
113–115
174–177
176–180
127–131
156–158
199–203
124–128
64–65
133–135
94–95
114–115
177
183–185
127–131
157–158
201–202
125–127
1j
2j
1
sure. A mixture of 4H-1,2,4-triazol-4-amine (0.42 g,
5 mmol) and potassium carbonate (0.69 g, 5 mmol) in
toluene (60 mL) was added to 0.1 g of C, and the
mixture was refluxed for 12 h. The product (D) was
separated with a strong magnet, washed repeatedly
with ethanol and water, and dried under reduced
pressure. A 0.1-g sample of D was added to a sus-
pension of copper(II) chloride (0.85 g, 5 mmol) in
ethanol, and the mixture was vigorously stirred for 8 h
at 80°C. The resulting copper nanocatalyst (E) was
separated with a strong magnet, washed with ethanol,
and air-dried.
1496, 1302, 1206, 1036, 815, 561. H NMR spectrum
(90 MHz, CDCl3), δ, ppm: 8.39 s (1H), 6.96 m (3H),
2.29 s (6H).
1-(4-Methylphenyl)-1H-tetrazole (2c). IR spec-
trum (nujol), ν, cm–1: 3027, 2914, 2857, 1672, 1608,
1587, 1521, 1506, 1408, 1313, 1217, 1202, 1174,
1110, 1040, 985, 938, 821, 738, 716, 644, 578.
1H NMR spectrum (90 MHz, CDCl3), δ, ppm: 8.16 s
(1H), 7.27–6.92 m (4H), 2.30 s (3H).
1-(4-Methoxyphenyl)-1H-tetrazole (2d). IR spec-
trum (nujol), ν, cm–1: 1667, 1504, 1464, 1243, 1034,
1
826. H NMR spectrum (90 MHz, CDCl3), δ, ppm:
1-Aryl-1H-tetrazoles 2a–2j (general procedure).
A mixture of 2 mmol of aromatic amine 1a–1j, 0.13 g
(2 mmol) of sodium azide, 0.296 g (2 mmol) of triethyl
orthoformate, and 50 mg of the copper nanocatalyst
was stirred at 100°C until no further progress in the
conversion was observed according to the TLC data.
The mixture was allowed to cool down to room tem-
perature, the catalyst was separated by strong magnet,
the mixture was poured onto ice, and the organic layer
was extracted with ethyl acetate (2 ×20 mL). The
combined extracts were dried over anhydrous MgSO4,
filtered, and evaporated, and the residue was recrys-
tallized from ethyl acetate–hexane (1:10). The yields
and melting points of tetrazoles 2a–2j are given in
Table 4.
8.05 s (1H), 6.88 m (4H), 3.7 s (3H).
1-[4-(1H-Tetrazol-1-yl)phenyl]ethan-1-one (2e).
IR spectrum (KBr), ν, cm–1: 3059, 2996, 2962, 1674,
1603, 1589, 1503, 1483, 1411, 1359, 1324, 1303,
1271, 1211, 1186, 1172, 997, 957, 910, 841, 815, 734,
685, 635, 590. 1H NMR spectrum (90 MHz, CDCl3), δ,
ppm: 8.29 s (1H), 8.00–7.09 m (4H), 2.59 s (3H).
1-(4-Bromophenyl)-1H-tetrazole (2f). IR spec-
trum (KBr), ν, cm–1: 3527, 3151, 3045, 2855, 1660,
1589, 1575, 1483, 1402, 1312, 1291, 1224, 1206,
1073, 1008, 827. 1H NMR spectrum (90 MHz, CDCl3),
δ, ppm: 8.07 s (1H), 7.40 d (2H, J = 8.6 Hz), 6.90 d
(2H, J = 8.6 Hz).
1-(2-Chlorophenyl)-1H-tetrazole (2g). IR spec-
trum (KBr), ν, cm–1: 2998, 2866, 1666, 1583, 1502,
1475, 1454, 1439, 1376, 1309, 1264, 1207, 1132,
1058, 1039, 1000, 935, 825, 752, 702, 657. H NMR
spectrum (90 MHz, CDCl3), δ, ppm: 8.07 s (1H), 7.44–
1-Phenyl-1H-tetrazole (2a). IR spectrum (KBr), ν,
cm–1: 3051, 2925, 2854, 1678, 1660, 1585, 1487, 1448,
1316, 1279, 1227, 1209, 1171, 1153, 1076, 986, 899,
1
1
806, 765, 754, 694, 619, 593. H NMR spectrum
(90 MHz, CDCl3), δ, ppm: 8.27 s (1H), 6.98–
7.10 m (4H).
7.60 m (5H).
1-(4-Chlorophenyl)-1H-tetrazole (2h). IR spec-
trum (KBr), ν, cm–1: 2925, 1663, 1581, 1488, 1405,
1311, 1292, 1226, 1205, 1172, 1090, 1006, 984, 829,
1-(2,4-Dimethylphenyl)-1H-tetrazole (2b). IR
spectrum (KBr), ν, cm–1: 3157, 3015, 2876, 1665,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019

SYNTHESIS OF TETRAZOLES FROM AMINES
1597
1
9. Zhao-Xu, C. and Heming, X., Int. J. Quantum Chem.,
2000, vol. 79, p. 350.
https://doi.org/10.1007/s10973-014-3643-4
10. Ek, F., Wistr, L.-G., and Frejd, T., Tetrahedron, 2003,
vol. 59, p. 6759.
https://doi.org/10.1016/S0040-4020(03)00818-4
11. Flippin, L.A., Tetrahedron Lett., 1991, vol. 32, p. 6857.
https://doi.org/10.1016/0040-4039(91)80425-6
12. Rhonnstad, P. and Wensbo, D., Tetrahedron Lett., 2002,
vol. 43, p. 3137.
810, 700, 650, 631, 570. H NMR spectrum (90 MHz,
CDCl3), δ, ppm: 8.09 s (1H), 7.28 d (2H, J = 6.7 Hz),
6.96 d (2H, J = 6.7 Hz).
1-(4-Nitrophenyl)-1H-tetrazole (2i). IR spectrum
(nujol), ν, cm–1: 3105, 2985, 1660, 1599, 1579, 1508,
1396, 1344, 1313, 1301, 1238, 1205, 1173, 1107, 989,
958, 861, 845, 784, 750, 708, 687, 642. 1H NMR spec-
trum (90 MHz, acetone-d6), δ, ppm: 8.52 s (1H), 8.23 d
(2H, J = 8.8 Hz), 7.57 d (2H, J = 8.8 Hz).
https://doi.org/10.1016/S0040-4039(02)00490-2
13. Modarresi-Alam, A.R., Khamooshi, F., Rostami-
zadeh, M., Kieykha, H., Nasrollahzadeh, M.,
Bijanzadeh, H.R., and Kleinpeter, E., J. Mol. Struct.,
2007, vol. 841, p. 61.
https://doi.org/10.1016/j.molstruc.2006.11.058
14. Sandmann, G., Schneider, C., and Böger, P.,
Z. Naturforsch., Teil C, 1996, vol. 51, p. 534.
15. Ponec, V. and Bond, G.C., Catalysis by Metals and
Alloys, Amsterdam: Elsevier: 1995.
16. Lim, C.W. and Lee, I.S., Nano Today, 2010, vol. 5,
p. 412.
https://doi.org/10.1016/j.nantod.2010.08.008
17. Butler, R.N., Adv. Heterocycl. Chem., 1977, vol. 21,
p. 323.
https://doi.org/10.1016/S0065-2725(08) 60735-7
18. Jin, T., Kitahara, F., Kamijo, S., and Yamamoto, Y.,
Tetrahedron Lett., 2008, vol. 49, p. 2824.
https://doi.org/10.1016/j.tetlet.2008.02.115
19. Habibi, D., Nasrollahzadeh, M., Faraji, A., and Bayat,
Y., Tetrahedron, 2010, vol. 66, p. 3866.
https://doi.org/10.1016/j.tet.2010.03.003
20. Habibi, D. and Nasrollahzadeh, M., Synth. Commun.,
2010, vol. 40, p. 3159.
1-(3-Trifluoromethylphenyl)-1H-tetrazole (2j).
IR spectrum (KBr), ν cm–1: 3275, 3220, 3140, 3005,
1
2981, 2940, 2840, 1620, 1585. H NMR spectrum
(90 MHz, DMSO-d6), δ, ppm: 8.19 s (1H), 7.60–
7.20 m (4H).
ACKNOWLEDGMENTS
The authors are grateful to the Bu-Ali Sina University,
Hamedan, Iran, for the financial support of this work.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
REFERENCES
1. Wittenberger, S.J., Org. Prep. Proced. Int., 1994, vol. 26,
p. 499.
https://doi.org/10.1080/00304949409458050
2. Butler, R.N., Comprehensive Heterocyclic Chemistry II,
Katritzky, A.R., Rees, C.W., and Scriven, E.F.V., Eds.,
Oxford: Pergamon, 1996, vol. 4, p. 621.
https://doi.org/10.1016/B978-008096518-5.00095-2
3. Herr, R.J., Bioorg Med. Chem., 2002, vol. 10, p. 3379.
https://doi.org/10.1016/S0968-0896(02)00239-0
4. Peet, N.P., Baugh, L.E., Sundler, S., Lewis, J.E.,
Matthews, E.H., Olberding, E.L., and Shah, D.N., J. Med.
Chem., 1986, vol. 29, p. 2403.
https://doi.org/10.1080/00397910903370683
21. Nasrollahzadeh, M., Habibi, D., Shahkarami, Z., and
Bayat, Y., Tetrahedron, 2009, vol. 65, p. 10715.
https://doi.org/10.1016/j.tet.2009.10.029
22. Habibi, D. and Nasrollahzadeh, M., Monatsh. Chem.,
2012, vol. 143, p. 925.
https://doi.org/10.1021/jm00161a045
https://doi.org/10.1007/s00706-011-0670-8
23. Habibi, D., and Nasrollahzadeh, M., Synth. Commun.,
2012, vol. 41, p. 2023.
5. Girijavallabhan, V.M., Pinto, P.A., Genguly, A.K., and
Versace, R.W., EP Patent no. 274867, 1988; Chem.
Abstr., 1989, vol. 110, no. 23890.
https://doi.org/10.1080/00397911.2010.548620
24. Habibi, D., Heydari, S., Afsharfarnia, M., and Rostami,
Z., Appl. Organomet. Chem., 2017, vol. 31, p. e3826.
https://doi.org/10.1002/aoc.3826
25. Habibi, D., Heydari, S., Gil, A., Afsharfarnia, M.,
Faraji, A., Karamian, R., and Asadbegy, M., Appl.
Organomet. Chem., 2018, vol. 32, p. e4005.
https://doi.org/10.1002/aoc.4005
6. Akimoto, H., Ootsu, K., and Itoh, F., EP Patent no.
530537, 1993; Chem. Abstr., 1993. vol. 119, no. 226417;
Mitch, C.H. and Quimby, S.J., WO Patent Appl. Pub.
no. 98/51312, 1998; Chem. Abstr., 1998, vol. 130,
no. 13997.
7. Jursic, B.S., and LeBlanc, B.W., J. Heterocycl. Chem.,
1998. vol. 35, p. 405.
https://doi.org/10.1002/jhet. 5570350224
26. Ariannezhad, M., Habibi, D., and Heydari, S.,
Polyhedron, 2019, vol. 160, p. 170.
8. John, E.O., Kirchmeier, R.L., and Shreeve, J.M., Inorg.
Chem., 1989, vol. 28, p. 4629.
https://doi.org/10.1039/C4RA06463A
https://doi.org/10.1016/j.poly.2018.12.037
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019