1983
AZA-MICHAEL ADDITION OF PYRAZOLES TO MALEIC ACID
2-[3(5)-Methyl-1H-pyrazol-1-yl]butanedioic acid
(Va, Vb) was obtained similarly from 8.2 g (0.1 mol)
of 3(5)-methylpyrazole II and 7.7 g (0.11 mol) of
maleic acid. Yield 15.8 g (80%), mp 200°C. IR spec-
IR spectra were obtained using a Nexus instrument
(Thermo Nicolet Corporation, USA). H NMR spectra
of the solutions in DMSO–CCl4 (1 : 3) were recorded
with a Varian Mercury spectrometer (300 MHz).
Elemental analysis was performed using a Korshun–
Klimova apparatus.
1
1
trum, ν, cm–1: 1530 (ring), 1680 (COOH). H NMR
spectrum, δ, ppm (J, Hz): 2.19 s (3H, CH3), 2.20 s (3H,
CH3), 2.93 m (1H, CH2), 3.11 m (1H, CH2), 5.14 m
(2H, NCH2), 5.94 d (1H, =CH, J 2.2), 7.21 d (1H,
=CH, J 2.4), 7.49 d (1H, =CH, J 2.2), 12.20 br.s (2H,
COOH). Found, %: C 48.80; H 5.49; N 14.38.
C8H10N2O4. Calculated, %: C 48.49; H 5.09; N 14.14.
ACKNOWLEDGMENTS
This work was supprted by State Committee
Science MES RA, in frame of the research project
no. SCS 13Ar_2e031.
After fractional recrystallization of a mixture of
isomers Va and Vb from water, isomer Va (50%) was
isolated, mp. 215–218°C. H NMR spectrum, δ, ppm
REFERENCES
1
(J, Hz): 2.19 s (3H, CH3), 2.93 d.d (1H, CH2, J 16.9,
7.2), 3.11 d.d (1H, CH2, J 16.9, 6.7), 5.14 d.d (1H, CH,
J 7.2,6.7), 5.93 d (1H, =CH, J 2.2), 7.48 d (1H, =CH,
J 2.2), 12.4 br.s (2H, COOH).
1. Hayotsyan, S.S., Khachatryan, A.N., Baltayan, A.O.,
Attaryan, H.S., and Hasratyan, G.V., Russ. J. Gen.
Chem., 2015, vol. 85, no. 4, p. 993. DOI: 10.1134/
S1070363215040398.
2-(3,5-Dimethyl-1H-pyrazol-1-yl)butanedioic acid
(VI) was obtained similarly from 9.6 g (0.1 mol) of
3,5-dimethylpyrazole III and 7.7 g (0.11 mol) of
maleic acid. Yield 20.4 g (96%), mp 220°C [5]. IR
2. Khachatryan, A.N., Hayotsyan, S.S., Attaryan, H.S., and
Hasratyan, G.V., Russ. J. Gen. Chem., 2015, vol. 85,
no. 4, p. 996. DOI: 10.1134/S1070363215040404.
3. Nesmeyanov, A.N., Rybinskaya, M.I., and Rybin, L.V.,
1
spectrum, ν, cm–1: 1540 (ring), 1690 (COOH). H
Russ. Chem. Rev., 1967, vol. 36, no. 7, p. 453.
NMR spectrum, δ, ppm (J, Hz): 2.12 s (3H, CH3), 2.28
s (3H, CH3), 3.00 d.d (1H, CH2, J 17.1, 8.0), 3.15 d.d
(1H, CH2, J 17.1, 5.8), 5.03 d.d (1H, CH, J 8.0, 5.8),
5.7 q (1H, =CH, J 0.7), 12.30 br.s (2H, COOH).
Found, %: C 50.45; H 5.38; N 13.56. C9H12N2O4.
Calculated, %: C 50.94; H 5.70; N 13.20.
4. Darbinyan, E.G., Matsoyan, M.G., Oganesyan, K.G.,
Mitardzyan, Yu.B., Saakyan, A.A., and Matsoyan, S.G.,
USSR Inventors Certificate 688499, 1979.
5. Grandbeg, I.I. and Kost, A.N., Zh. Obshch. Khim., 1959,
vol. 29, no. 4, p. 1099.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 8 2015