NMR-STUDY OF C-TRIMETHYLSILYLAZOLE AND N-TRIMETHYLSILYLAZOLE DERIVATIVES

C- and N-trimethylsilylazole derivatives were studied by H-1, C-13 and Si-29 NMR spectroscopy. Degenerated prototropic tautomerism of 4-trim ethylsilylpyrazole in methanol and the silylotropy of 1-trimethylsilyl -4-methylpyrazole in a neat liquid were investigated for the first tim e. 3- and 5-tautomers of 3(5)-methylpyrazole in a ratio of 54:46 were found in methanol by use C-13 NMR spectroscopy (T-c = 230 K, Delta G(c )(not equal) = 10 kcal mol(-1)). (C) 1998 John Wiley & Sons, Ltd.