4-functionally substituted 3-hetarylpyrazoles: XX. Synthesis of derivatives of 5-(pyrasol-4-yl)-1,2,4-triazole and 3-(pyrazol-4-yl)-1,2,4-triazolo[3,4-c] [1,4]oxazine

Article abstract of DOI:10.1134/S107042801302019X

N-Methylimines of 3-aryl-1-phenylpyrazole-4-carbaldehyde react with ethyl 2-aryl-hydrazino-2-chloroacetate with the formation of ethyl 1-aryl-5-(pyrazole-4-yl)-4,5-dihydro-1H-1,2,4-triazolecarboxylates. Analogous reactions of pyrazol-4-carbaldehyde N-(2-h

Full text of DOI:10.1134/S107042801302019X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 2, pp. 294−297. © Pleiades Publishing, Ltd., 2013.
Original English Text © M.K. Bratenko, N.V. Panasenko, M.V. Vovk, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 2, pp. 295−299.
4-Functionally Substituted 3-Hetarylpyrazoles: XX.*
Synthesis of Derivatives
of 5-(Pyrasol-4-yl)-1,2,4-triazole and 3-(Pyrazol-4-yl)-1,2,4-
triazolo[3,4-c][1,4]oxazine
M. K. Bratenkoa, N. V. Panasenkoa, and M. V. Vovkb
aBukovina State Medical University, Chernovtsy, Ukraine
bInstitute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev, 02094 Ukraine
e-mail: mvovk@i.com.ua
Received July 4, 2012
Abstract—N-Methylimines of 3-aryl-1-phenylpyrazole-4-carbaldehyde react with ethyl 2-aryl-hydrazino-2-
chloroacetate with the formation of ethyl 1-aryl-5-(pyrazole-4-yl)-4,5-dihydro-1H-1,2,4-triazolecarboxylates.
Analogous reactions of pyrazol-4-carbaldehyde N-(2-hydroxy)ethylimines results in derivatives of 3-(pyrazol-4-
yl)-1,2,4-triazolo[3,4-c][1,4]-oxazines.
DOI: 10.1134/S107042801302019X
carbonylnitrilimines. In the case of N-methylimines
Ia–Ie ethyl 5-(3-arylpyrazol-4-yl)- 4,5-dihydro-1H-1,2,4-
triazolecarboxylates IIIa–IIIj formed in 64–85% yields.
Imines of pyrazole-4-carbaldehyde recently found an
application as convenient initial compounds for subse-
quent functionalization with versatile heterocyclic frag-
ments. On their basis pyrazoles were obtained substituted
in the position 4 by thiazolidine [2–5], 1,2,4-oxadiazoline
[2], benzoxazoline or benzthiazoline [6, 7] rings. Taking
into account the biophore properties of both pyrazoles
functionalized in the position 4 [8], and 5-substituted
derivatives of 1,2,4-triazole [9–11] it was considered
appropriate to develop a convenient approach to these
heterocyclic ensembles.
At the use of N-(2-hydroxy)ethylimines If–Ij we
unexpectedly obtained as reaction products derivatives of
3-(pyrazol-4-yl)-1,2,4-triazolo[3,4-c][1,4]oxazines IVa–
IVg isolated in high yields. They formed most probably by
the subsequent cyclization of primarily arising triazolines
IIIj–IIIq containing in the position 4 a hydroxyethyl
substituent. The special feature of the observed fusion
of a 1,4-oxazine and a 1,2,4-triazoline rings consists in
the occurrence of the intramolecular acylation of the
β-hydroxyethyl fragment wih the ethoxycarbonyl group
at room temperature in the materially neutral medium.
In the IR spectra of ethyl triazole-3-carboxylates IIIa–
IIIj the carbonyl group gives rise to an absorption band
in the region 1720–1725 cm–1, and in the spectra of
triazoloxazinones IVa–IVg, at 1735–1745 cm–1. In the
1H NMR spectra of compounds IIIa–IIIj characteristic
signal of H5 protons appears at 6.25–6.68 ppm, and in the
spectra of compounds IVa–IVg singlets of H3 protons
are observed at 6.57–6.82 ppm In the spectra of the lat-
ter also the signals of the ethoxy groups are absent, and
alongside the mass spectra it served a convincing proof
of their structure.
Proceeding from the published sources on the synthe-
sis of 5-aryl-1,2,4-triazolines [12–14] we examined the
reaction of [3+2]-cycloaddition of alkoxycarbonylnitri-
limines to the pyrazole-4-carbaldehyde imines.
It was found experimentally that unlike arylaldimines
[13] the structure of pyrazolulaldimines was very sensi-
tive to this type reactions, and we succeeded to obtain
a positive result only with pyrazole-4-carbaldehyde N-
alkylimines Ia–Ij. The latter reacted selectively with ethyl
2-arylhydrazino-2-chloroacetetes IIa–IId in benzene at
room temperature in the triethylamine, i.e., under the
conditions of generation of the corresponding ethoxy-
* For Communication XIX, see [1].
294

4-FUNCTIONALLY SUBSTITUTED 3-HETARYLPYRAZOLES: XX.
295
O
N
CO2Et
O
N
R
N
N
Cl
CO2Et
Ar'
N
N
N
C
N
N
Ar'
Ar
Ar'
Ar
R
R = CH2CH2OH
_EtOH
Et3N
Ar
+
N N
H
Ph
N N
N
N
Ph
Ph
Iа_Ij
IIIа_IIIc
IIа_IId
IVа_IVg
I, R = Ме, Ar = 4-FC6H4 (а), 4-ClC6H4 (b), 4-МеC6H4 (c), 3,4-(МеО)2C6H3 (d), benzofuran-2-yl (e); R = СН2СН2ОН, Ar = 4- FC6H4
(f), 4-ClC6H4 (g), 4-MeC6H4 (h), 4-(F2HCO)C6H4 (i), 3,4-(MeO)2C6H4 (j); II, Ar' = 4-FC6H4 (a), 4-ClC6H4 (b), 4-MeC6H4 (c), 4-H2N-
SO2C6H4 (d); III, R = Me: Ar = Ar' = 4-FC6H4 (a), 4-ClC6H4 (b); Ar = 4-ClC6H4, Ar' = 4-MeC6H4 (c); Ar = 4-MeC6H4, Ar' = 4-ClC6H4
(d);Ar = 3,4-(MeO)2C6H3, Ar' = 4-FC6H4 (e), 4-MeC6H4 (f);Ar = benzofuran-2-yl, Ar' = 4-FC6H4 (g), 4-ClC6H4 (h), 4-MeC6H4 (i), C6H5
(j); R = CH2CH2OH: Ar = 4-FC6H4, Ar' = 4-MeC6H4 (k); Ar = 4-ClC6H4, Ar' = 4-MeC6H4(l); Ar = 4-(F2HCO)C6H4, Ar' = 4-FC6H4 (m),
4-MeC6H4 (n), 4-NH2SO2C6H4 (o); Ar = 3,4-(MeO)2C6H3, Ar' = 4-FC6H4 (p), 4-MeC6H4 (q); IV, Ar = 4-FC6H4, Ar' = 4-MeC6H4 (a);
Ar = 4-ClC6H4,Ar' = 4-MeC6H4 (b);Ar = 4-(F2HCO)C6H4,Ar’= 4-FC6H4 (c), 4-MeC6H4 (d), 4-NH2SO2C6H4 (e);Ar = 3,4-(MeO)2C6H3,
Ar' = 4-FC6H4 (f), 4-MeC6H4 (g).
EXPERIMENTAL
1H-1,2,4-triazole-3-carboxylate (IIIb). Yield 64%, mp
176–177°C. IR spectrum, ν, cm–1: 1725 (C=O). 1H NMR
spectrum, δ, ppm: 1.32 t (3H, CH3, J 6.6 Hz), 2.96 s (3H,
IR spectra were recorded on a spectrophotometer
UR-20 from pellets with KBr. 1H and 13C NMR spectra
were registered on a spectrometer Bruker Avance DRX-
500 (500.13 MHz), from solutions in (CD3)2SO, internal
reference TMS. GC-MS spectra were taken on an instru-
ment Aligent 1100/DAD/HSD/VLG 119562.
CH3N), 4.33 q (2H, CH2O, J 6.6 Hz), 6.68 s (1H, H5
tri-
azole), 6.98 d (2Harom, J 7.8 Hz), 7.23 d (2Harom, J 7.8 Hz),
7.31–7.77 m (7Harom), 7.98 d (2Harom, J 7.8 Hz), 9.00 s
(1H, H5pyrazole). Found, %: C 62.08; H 4.33; N 13.65.
[M + 1]+ 521. C27H23Cl2N5O2. Calculated, %: C 62.31;
H 4.45; N 13.46. M 520.42.
Compounds IIIa–IIIj, IVa–IVg. To a slurry of
2 mmol of compound IIa–IId in 15 ml of chloroform was
added at stirring 0.29 ml (2.1 mmol) of triethylamine, and
0.5 h later, 2 mmol of imine Ia–Ij in 10 ml of chloroform.
The reaction mixture was stirred at room temperature
for 18–20 h, the solvent was evaporated, the residue
was washed with water (3 × 15 ml), dissolved in 20 ml
of chloroform, the solution was dried with anhydrous
sodium sulfate, filtered, chloroform was evaporated, the
residue was crystallized from ethanol.
Ethyl 4-methyl-1-(4-methylphenyl)-5-[1-phenyl-
3-(4-chlorophenyl)-1H-pyrazol-4-yl]-4,5-dihydro-
1H-1,2,4-triazole-3-carboxylate (IIIc). Yield 73%,
mp 145–146°C. IR spectrum, ν, cm–1: 1720 (C=O).
1H NMR spectrum, δ, ppm: 1.33 t (3H, CH3, J 6.8 Hz),
2.13 s (3H, CH3), 2.95 s (3H, CH3N), 4.33 q (2H, CH2O,
J 6.8 Hz), 6.59 s (1H, H5triazole), 6.90 d (2Harom, J 7.5 Hz),
6.98 d (2Harom, J 7.5 Hz), 7.30–7.72 m (7Harom), 7.98 d
(2Harom, J 8.0 Hz), 8.99 s (1H, H5pyrazole). Found, %:
C 67.52; H 5.09; N 13.84. [M + 1]+ 501. C28H26ClN5O2.
Calculated, %: C 67.26; H 5.24; N 14.01. M 500.00.
Ethyl 4-methyl-5-[1-phenyl-3-(4-fluorophenyl)-
1H-pyrazol-4-yl]-1-(4-fluorophenyl)-4,5-dihydro-
1H-1,2,4-triazole-3-carboxylate (IIIa). Yield 85%, mp
Ethyl 4-methyl-5-[3-(4-methylphenyl)-1-phenyl-
1H-pyrazol-4-yl]-1-(4-chlorophenyl)-4,5-dihydro-
1H-1,2,4-triazole-3-carboxylate (IIId). Yield 69%,
97–98°C. IR spectrum, ν, cm–1: 1725 (C=O). H NMR
1
spectrum, δ, ppm: 1.30 t (3H, CH3, J 6.5 Hz), 2.87 s (3H,
CH3N), 4.30 q (2H, CH2O, J 6.5 Hz), 6.28 s (1H, H5triazole),
6.93–8.61 m (13Harom), 8.98 s (1H, H5pyrazole). Found, %:
C 66.24; H 4.64; N 14.09. [M + 1]+ 488. C27H23F2N5O2.
Calculated, %: C 66.52; H 4.76; N 14.37. M 487.51.
1
mp 152–153°C. IR spectrum, ν, cm–1: 1720 (C=O). H
NMR spectrum, δ, ppm: 1.31 t (3H, CH3, J 6.8 Hz),
2.35 s (3H, CH3), 2.84 s (3H, CH3N), 4.29 q (2H, CH2O,
J 6.8 Hz), 6.36 s (1H, H5triazole), 6.88 d (2Harom, J 7.8 Hz),
7.18–7.52 m (9Harom), 7.92 d (2Harom, J 7.8 Hz), 8.92 s
(1H, H5pyrazole). Found, %: C 67.54; H 5.18; N 13.78. [M +
Ethyl 4-methyl-5-[1-phenyl-3-(4-chlorophenyl)-
1H-pyrazol-4-yl]-1-(4-chlorophenyl)-4,5-dihydro-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 2 2013

BRATENKO et al.
296
1]+ 501. C28H26ClN5O2. Calculated, %: C 67.26; H 5.24;
N 14.01. M 500.00.
2.30 s (3H, CH3), 2.87 s (3H, CH3N), 4.29 q (2H, CH2O,
J 6.8 Hz), 6.29 s (1H, H5triazole), 6.83 d (2Harom, J 7.6 Hz),
6.97 d (2Harom, J 7.6 Hz), 7.35–7.95 m (9Harom), 8.98 s
(1H, H5pyrazol). Found, %: C 71.44; H 5.23; N 13.61. [M +
1]+ 506. C30H27N5O3. Calculated, %: C 71.27; H 5.38;
N 13.85. M 505.58.
Ethyl 4-methyl-5-[3-(3,4-dimethoxyphenyl)-1-
phenyl-1H-pyrazol-4-yl]-1-(4-fluorophenyl)-4,5-
dihydro-1H-1,2,4-triazole-3-carboxylate (IIIe). Yield
81%, mp 116–117°C. IR spectrum, ν, cm–1: 1725 (C=O).
1H NMR spectrum, δ, ppm: 1.29 t (3H, CH3, J 6.8 Hz),
2.87 s (3H, CH3N), 3.77 s (3H, CH3O), 3.79 s (3H,
Ethyl 5-[3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-
4-yl]-4-methyl-1-phenyl-4,5-dihydro-1H-1,2,4-tri-
azole-3-carboxylate (IIIj). Yield 68%, mp 118–119°C.
IR spectrum, ν, cm–1: 1720 (C=O). 1H NMR spectrum,
δ, ppm: 1.31 t (3H, CH3, J 6.6 Hz), 2.88 s (3H, CH3N),
4.30 q (2H, CH2O, J 6.6 Hz), 6.35 s (1H, H5triazole),
6.79–7.62 m (11Harom), 7.94 d (2Harom, J 8.0 Hz), 9.01 s
(1H, H5pyrazole). Found, %: C 70.58; H 5.07; N 14.47. [M +
1]+ 492. C29H25N5O3. Calculated, %: C 70.86; H 5.13;
N 14.25. M 491.55.
CH3O), 4.29 q (2H, CH2O, J 6.8 Hz), 6.26 s (1H, H5
tri-
azole), 6.97–7.54 m (10Harom), 7.93 d (2Harom, J 7.2 Hz),
8.97 s (1H, H5pyrazole). Found, %: C 65.87; H 5.86;
N 13.14. [M + 1]+ 516. C28H26FN5O4. Calculated, %:
C 66.04; H 5.91; N 12.84. M 515.55.
Ethyl 4-methyl-1-(4-methylphenyl)-5-[3-(3,4-
dimethoxyphenyl)-1-phenyl-1H-pyrazol-4-yl]-4,5-
dihydro-1H-1,2,4-triazole-3-carboxylate (IIIf). Yield
79%, mp 139–140°C. IR spectrum, ν, cm–1: 1720 (C=O).
1H NMR spectrum, δ, ppm: 1.30 t (3H, CH3, J 6.6 Hz),
2.16 s (3H, CH3), 2.87 s (3H, CH3N), 3.79 s (6H, 2CH3O),
4.28 q (2H, CH2O, J 6.6 Hz), 6.25 s (1H, H5triazole),
6.88–7.94 m (12Harom), 8.95 s (1H, H5pyrazole) Found, %:
C 68.38; H 5.86; N 13.55. [M + 1]+ 526. C30H31N5O4.
Calculated, %: C 68.56; H 5.94; N 13.32. M 525.61.
2-(4-Methylphenyl)-3-[1-phenyl-3-(4-fluoro-
phenyl)-1H-pyrazol-4-yl]-2,3,5,6-tetrahydro-8H-1,2,4-
triazolo[3,4-C][1,4]oxazin-8-one (IVa). Yield 76%, mp
181–182°C. IR spectrum, ν, cm–1: 1735 (C=O). 1H NMR
spectrum, δ, ppm: 2.16 s (3H, CH3), 3.15 m, 3.41 m (2H,
CH2N), 4.41 m, 4.53 m (2H, CH2O), 6.57 s (1H, H3),
6.80 d (2Harom, J 8.0 Hz), 6.97 d (2Harom, J 8.0 Hz), 7.29–
7.68 m (7Harom), 7.92 d (2Harom, J 7.8 Hz), 8.95 s (1H,
H5pyrazole). Found, %: C 69.56; H 4.68; N 14.67. [M +
1]+ 468. C27H22FN5O2. Calculated, %: C 69.37; H 4.74;
N 14.98. M 467.51.
Ethyl 5-[3-(benzofuran-2-yl)-1-phenyl-1H-pyr-
azol-4-yl]-4-methyl-1-(4-fluorophenyl)-4,5-dihydro-
1H-1,2,4-triazole-3-carboxylate (IIIg). Yield 69%,
mp 123–124°C. IR spectrum, ν, cm–1: 1720 (C=O).
1H NMR spectrum, δ, ppm: 1.30 t (3H, CH3, J 6.8 Hz),
2.86 s (3H, CH3N), 4.29 q (2H, CH2O, J 6.8 Hz), 6.29 s
(1H, H5triazole), 6.94–7.27 m (4Harom), 7.47–7.95 m (9Ha-
rom), 9.00 s (1H, H5pyrazole). Found, %: C 68.58; H 4.69;
N 13.55. [M + 1]+ 510. C29H24FN5O3. Calculated, %:
C 68.36; H 4.76; N 13.74. M 509.54.
2-(4-Methylphenyl)-3-[1-phenyl-3-(4-chloro-
phenyl)-1H-pyrazol-4-yl]-2,3,5,6-tetrahydro-8H-
1,2,4-triazolo[3,4-C][1,4]oxazin-8-one (IVb). Yield
79%, mp 204–205°C. IR spectrum, ν, cm–1: 1740 (C=O).
1H NMR spectrum, δ, ppm: 2.16 s (3H, CH3), 3.14 m,
3.34 m (2H, CH2N), 4.43 m, 4.51 m (2H, CH2O), 6.58 s
(1H, H3), 6.81 d (2Harom, J 7.8 Hz), 6.96 d (2Harom
,
Ethyl 5-[3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-
4-yl]-4-methyl-1-(4-chlorophenyl)-4,5-dihydro-1H-
1,2,4-triazole-3-carboxylate (IIIh). Yield 78%, mp 141–
J 7.8 Hz), 7.37–7.68 m (7Harom), 7.92 d (2Harom, J 7.8 Hz),
8.97 s (1H, H5pyrazole). Found, %: C 66.78; H 4.54;
N 14.55. [M + 1]+ 484. C27H22ClN5O2. Calculated, %:
C 67.01; H 4.58; N 14.47. M 483.96.
1
142°C. IR spectrum, ν, cm–1: 1725 (C=O). H NMR
spectrum, δ, ppm: 1.31 t (3H, CH3, J 6.6 Hz), 2.88 s (3H,
CH3N), 4.30 q (2H, CH2O, J 6.6 Hz), 6.38 s (1H, H5
3-[3-(4-Difluoromethoxyphenyl)-1-phenyl-1H-
pyrazol-4-yl]-2-(4-fluorophenyl)-2,3,5,6-tetrahydro-
8H-1,2,4-triazolo[3,4-C][1,4]oxazin-8-one (IVc). Yield
64%, mp 166–167°C. IR spectrum, ν, cm–1: 1735 (C=O).
1H NMR spectrum, δ, ppm: 3.15 m, 3.42 m (2H, CH2N),
4.34 m, 4.54 m (2H, CH2O), 6.57 s (1H, H3), 6.91–7.55 m
(9Harom + F2CHO), 7.71 d (2Harom, J 8.0 Hz), 7.92 d
(2Harom, J 7.8 Hz), 8.97 s (1H, H5pyrazole). Found, %:
C 62.71; H 3.84; N 13.21. [M + 1]+ 520. C27H20F3N5O3.
Calculated, %: C 62.43; H 3.88; N 13.48. M 519.49.
tri-
azole), 6.91 d (2Harom, J 7.8 Hz), 7.21 d (2Harom, J 7.8 Hz),
7.36–7.92 m (9Harom), 8.97 s (1H, H5pyrazole). Found, %:
C 66.47; H 4.52; N 13.51. [M + 1]+ 527. C29H24ClN5O3.
Calculated, %: C 66.22; H 4.60; N 13.31. M 526.00.
Ethyl 5-[3-(benzofuran-2-yl)-1-phenyl-1H-pyrazol-
4-yl]-4-methyl-1-(4-methylphenyl)-4,5-dihydro-
1H-1,2,4-triazole-3-carboxylate (IIIi). Yield73%,
mp 134–135°C. IR spectrum, ν, cm–1: 1725 (C=O).
1H NMR spectrum, δ, ppm: 1.31 t (3H, CH3, J 6.8 Hz),
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4-FUNCTIONALLY SUBSTITUTED 3-HETARYLPYRAZOLES: XX.
297
3-[3-(4-Difluoromethoxyphenyl)-1-phenyl-1H-
pyrazol-4-yl]-2-(4-methylphenyl)-2,3,5,6-tetrahydro-
8H-1,2,4-triazolo[3,4-C][1,4]oxazin-8-one (IVd). Yield
54%, mp 156–157°C. IR spectrum, ν, cm–1: 1745 (C=O).
1H NMR spectrum, δ, ppm: 2.16 s (3H, CH3), 3.15 m,
3.43 m (2H, CH2N), 4.42 m, 4.54 m (2H, CH2O), 6.57 s
CH2N), 3.81 s (6H, 2CH3O), 4.38 m, 4.53 m (2H, CH2O),
6.57 s (1H, H3), 6.86–7.53 m (10Harom), 7.92 d (2Harom
,
J 7.2 Hz), 8.94 C (1H, H5pyrazole). Found, %: C 68.11;
H 5.46; N 13.55. [M + 1]+ 510. C29H27N5O4. Calculated,
%: C 68.36; H 5.34; N 13.74. M 509.57.
(1H, H3), 6.82 d (2Harom, J 7.8 Hz), 6.98 d (2Harom
,
REFERENCES
J 7.8 Hz), 7.26–7.57 m (6H, 5Harom+ F2HCO), 7.72 d
(2Harom, J 8.0 Hz), 7.93 d (2Harom, J 8.0 Hz), 8.98 s (1H,
H5pyrazole). Found, %: C 65.52; H 4.66; N 13.44. [M +
1]+ 516. C28H23F2N5O2. Calculated, %: C 65.24; H 4.50;
N 13.58. M 515.52.
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3-[3-(4-Difluoromethoxyphenyl)-1-phenyl-1H-
pyrazol-4-yl]-2-(4-sulfamoylphenyl)-2,3,5,6-tetrahy-
dro-8H-1,2,4-triazolo[3,4-C][1,4]oxazin-8-one (IVe).
Yield 64%, mp 249–250°C. IR spectrum, ν, cm–1: 1745
(C=O). 1H NMR spectrum, δ, ppm: 3.21 m, 3.48 m (2H,
CH2N), 4.45 m, 4.57 m (2H, CH2O), 6.82 s (1H, H3),
6.93–7.69 m (11Harom), 7.91 d (2Harom, J 7.8 Hz), 8.99 s
(1H, H5pyrazole). Found, %: C 55.98; H 3.76; N 14.62.
[M + 1]+ 581. C27H22F2N6O5S. Calculated, %: C 55.86;
H 3.82; N 14.48. M 580.57.
3-[3-(3,4-Dimethoxyphenyl)-1-phenyl-1H-pyrazol-
4-yl]-2-(4-fluorophenyl)-2,3,5,6-tetrahydro-8H-
1,2,4-triazolo[3,4-C][1,4]oxazin-8-one (IVf). Yield
54%, mp 186–187°C. IR spectrum, ν, cm–1: 1745
1
(C=O). H NMR spectrum, δ, ppm: 3.13 m, 3.42 m
(2H, CH2N), 3.77 s (6H, 2CH3O), 4.38 m, 4.54 m (2H,
CH2O), 6.57 s (1H, H3), 6.95–7.53 m (10Harom), 7.92 m
(2Harom), 8.96 s (1H, H5pyrazole). Found, %: C 65.78;
H 4.56; N 13.85. [M + 1]+ 514. C28H24FN5O4. Calculated,
%: C 65.49; H 4.71; N 13.64. M 513.53.
12. Konwar, D., Boruah, R.C., and Sandhu, J.S., Ind. J. Chem.
B, 1997, vol. 36, p. 1050.
13. Tewari, R.S. and Parihar, P., Tetrahedron, 1983, vol. 39,
p. 129.
14. Molteni, G. and Ponti,A., Tetrahedron: Asymmetry., 2004,
vol. 15, p. 3711.
3-[3-(3,4-Dimethoxyphenyl)-1-phenyl-1H-pyrazol-
4-yl]-2-(4-methylphenyl)-2,3,5,6-tetrahydro-8H-1,2,4-
triazolo[3,4-C][1,4]oxazin-8-one (IVg). Yield 61%, mp
183–184°C. IR spectrum, ν, cm–1: 1740 (C=O). 1H NMR
spectrum, δ, ppm: 2.16 s (3H, CH3), 3.14 m, 3.42 m (2H,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 2 2013