UNUSUAL COURSE OF DIAZOLEES SILYLATION
1495
N
II
N
H
O
H
N
N
N
N
(c) −Et2NCOSiMe3
−Et2NH
III
Me
Me
Me
H
N
NC(O)OSiMe3
Me
IX
All starting compounds and solvents were carefully
purified and dried before use. Synthetic procedures and
sampling for analysis of all the substances were carried
out in the dry nitrogen atmosphere. The composition of
reaction mixtures and pure compounds was monitored
by GLC on a Shimadzu G-8 device (column 1500×3 mm
of stainless steel, stationary phase SE-30 on
Chromaton N-AW, carrier gas helium).
3,5-Dimethyl-1-(trimethylsilyl)-1H-pyrazole (V).
Through a mixture of 15 g of 3,5-dimethylpyrazole
and 16.23 g of hexamethyldisilazane was passed
carbon dioxide for 20 h at a temperature of 50–55°C.
By fractionation 19.14 g (85%) of compound V was
isolated, bp 77–78°C (10 mm Hg), nD20 1.4719 [5].
Trimethylsilyl-3(5)-methyl-1H-pyrazole-1-carbo-
xylate (IX). A mixture of 20 g of 3(5)-methylpyrazole
and 46.16 g of trimethylsilyl diethylcarbamate was
heated at a complete reflux to the end of diethylamine
release. By fractionation 44.47 g (92%) of compound
IX was isolated, bp 93–95°C (10 mm Hg), nD20 1.4552.
IR spectrum, ν, cm–1: 3120 (C=CH), 1690 (C=O),
Trimethylsilyl 1H-imidazole-1-carboxylate (II).
A mixture of 15 g of imidazole and 41.66 g of tri-
methylsilyl diethylcarbamate was heated at a complete
reflux to complete release of diethylamine. By frac-
tionation compound was isolated II, 36.88 g (91%), bp
100–101°C (2 mm Hg), nD20 1.4463. IR spectrum, ν,
1
1
cm–1: 3080 (C=CH), 1660 (C=O), 1520 (C=N). H
1520 (C=N). H NMR spectrum, δ, ppm: 0.41 s (9H,
SiCH3), 2.29 s (6H, CCH3), 6.01 s and 6.07 s (1H,
CH), 7.43 s and 7.45 s (1H, CH). Found, %: C 48.65;
H 7.23; N 14.41. C8H4N3O2Si. Calculated, %: C 48.46;
H 7.12; N 14.13.
NMR spectrum, δ, ppm: 0.37 s (9H, SiCH3), 6.95 s
(2H, NCH), 7.6 s (1H, NCHN). Found, %: C 45.32; H
6.37; N 15.34. C7H12N2O2Si. Calculated, %: C 45.63;
H 6.56; N 15.20.
Trimethylsilyl 3,5-dimethyl-1H-pyrazole-1-carbo-
xylate (III). A mixture of 15g of 3,5-dimethylpyrazole
and 29.56 g trimethylsilyl diethylcarbamate was heated
at a complete reflux to the end of diethylamine release.
By fractionation 30.81 g (93% ) of compound III was
isolated, bp 140–142°C (1 mm Hg), nD20 1.4483. IR
spectrum, ν, cm–1: 3180 (C=CH), 1690 (C=O), 1520
(C=N). 1H NMR spectrum, δ, ppm: 0.44 s (9H,
SiCH3), 2.23 s (6H, CCH3), 5.81 s (1H, CH). Found,
%: C 50.92; H 7.55; N 13.31. C9H16N2O2Si.
Calculated, %: C 50.91; H 7.60; N 13.19.
REFERENCES
1. Breederveld, H., Rec. Trav. Chim., 1962, vol. 81,
p. 276.
2. Sheludyakov, V.D., Kirilin, A.D., and Mironov, V.F.,
Zh. Obshch. Khim., 1975, vol. 45, no. 2, p. 479.
3. Sheludyakov, VD, Kirilin, A.D., and Mironov, V.F., Zh.
Obshch. Khim., 1977, vol. 47, no. 7, p. 1515.
4. Shmyreva, G.O., Shmakov, V.G., Golosova, R.M.,
Kostrukov, V.N., Sheludyakov, V.D., and Kirilin, A.D.,
Termodinamika organicheskikh soedinenii (Thermo-
dynamics of Organic Compounds), Gorkii: Gork. Gos.
Univ.. 1978, no. 7, p. 85.
1-Trimethylsilyl-1H-imidazole (IV). Through a
mixture of 15 g of imidazole and 19.20 g of hexa-
methyldisilazane was passed carbon dioxide for 20 h at
70°C. By fractionation 25.35 g (82%) of compound IV
was isolated, bp 92–93°C (10 mm Hg), nD20 1.4745 [5].
5. Sheludyakov, V.D., Kirilina, N.I., and Kirilin, A.D., Zh.
Obshch. Khim., 1976, vol. 50, no. 2, p. 472.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 81 No. 7 2011