M. S. Sorokin

NMR study of C- and N-trimethylsilylazole derivatives

C‐ and N‐trimethylsilylazole derivatives were studied by 1H, 13C and 29Si NMR spectroscopy. Degenerated prototropic tautomerism of 4‐trimethylsilylpyrazole in methanol and the silylotropy of 1‐trimethylsilyl‐4‐methylpyrazole in a neat liquid were investigated for the first time. 3‐ and 5‐tautomers of 3(5)‐methylpyrazole in a ratio of 54:46 were found in methanol by use 13C NMR spectroscopy (Tc=230 K, ΔGc≠=10 kcal mol‐1).

Selenium- and tellurium-containing silatrane derivatives having an ECH2Si fragment (E = Se, Te)

Previously unknown 1-(methylselenomethyl)-and 1-(phenyltelluromethyl)silatrane, bis(silatranylmethyl) selenide, bis(silatranylmethyl) telluride, bis(silatranylmethyl) diselenide, and dimethyl(triethoxysilylmethyl)telluronium, phenyl(silatranylmethyl)telluronium, methylbis(silatranylmethyl)selenonium, methylbis(silatranylmethyl)telluronium, and tris(silatranylmethyl)selenonium iodides were synthesized. The NMR spectra of these compounds, as well as of isostructural (methylchalcogenomethyl)triethoxysilanes, 1-(methylchalcogenomethyl)silatranes, the corresponding methylchalcogenonium iodides, methylorganyl(silatranylmethyl)chalcogenonium iodides, bis(trialkoxysilylmethyl) chalcogenides, and bis(silatranylmethyl) chalcogenides, in CDCl3, CD3OH, CD3CN, and DMSO-d6 were studied.

Reactions of (triethylstannylthioalkyl)trialkoxysilanes and (triethylstannylthioalkyl)trialkoxysilatranes with methyl iodide

Reactions of (triethylstannylthioalkyl)trimethoxysilanes Et3SnS(CH2)nSi(OMe)3 (n = 1, 2) and (triethylstannylthioalkyl)trialkoxysilatranes Et3Sn(CH2)nSa [hereinafter Sa = Si(OCH2CH2)3N is silatranyl group] with methyl iodide are studied for the first time. The results of the investigation of the reaction of 1-(2-alkylthioethyl)silatranes RSCH2CH2Sa (R = Me, Et) with methyl iodide are also discussed.

Reaction of methyl iodide with organylethynyl silatranylmethyl chalcogenides

The reactivity of organylethynyl silatranylmethyl chalcogenides RC=CYCH2Si(OCH2CH2)3N (R=Ph, Me3Si; Y=S, Se, Te) in the reaction with methyl iodide depending on the nature of the chalcogen Y, the substituent R at the triple bond, and the reaction conditions was studied.

1-Trimethoxysilylmethyl- and 1-(2,8,9-Trioxa-5-aza-1- silabicyclo(3.3.3)undecan-1-ylmethyl)-1,1-dimethyl-2-(3-alkoxy- 3-oxopropyl)hydrazinium Halides

Previously unknown 1,1-dimethyl-1-trimethoxysilylmethyl-2-(3-alkoxy-3-oxopropyl)hydrazinium and 1,1-dimethyl-1-(2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-ylmethyl)-2-(3-alkoxy-3-oxopropyl)-hydrazinium halides were synthesized, and physiological activity of 2-(3-ethoxy-3-oxopropyl)-1,1-dimethyl-1-(2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-ylmethyl)hydrazinium chloride and bromide was studied.

CATALYTIC SILYLOTROPY IN N-TRIMETHYLSILYLPYRAZOLE DERIVATIVES

Silylotropy in 4-substitutedN-trimethylsilypyrazoles is studied by dynamic1H,13C, and29Si NMR spectroscopy. The catalytic 1,2-migration of a trimethylsilyl group in 4-halo-N-trimethylsilylpyrazoles was detected. Silylotropy inN-trimethylsilylpyrazoles in the presence of halogens of trimethylhalosilanes is believed to proceed through formation ofN,N′-bis(trimethylsilyl)pyrazolium salts, the barrier of silylotropy in pyrazoles being markedly reduced.