S 98 Synthesis and the reactions of trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines [Electronic resource] / O. G. Khudina, E. V. Shchegol'kov, Ya. V. Burgart, M. I. Kodess, O. N. Kazheva, A. N. Chekhlov, G. V. Shilov, O. A. Dyachenko, V. I. Saloutin, O. N. Chupakhin // Journal of Fluorine Chemistry. - 2005. - Vol. 126, № 8. - P1230-1238 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The coupling of trifluoromethylated 1,3-diketones with (het)aryldiazonium chlorides results mainly in the formation of 1,2,3-triketones 2-(het)arylhydrazones while using hetarylamine with a NH-group at the ?-position of the heterocycle as the diazonium component gives 4,7-dihydroazolo[5,1-c]triazines due to cyclization at the trifluoroacetyl fragment. Trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 7-hydroxy-4,7-dihydroazolo[5,1-c]triazines react regio-selectively with methyl hydrazine and phenyl hydrazine to form 3-CF3-pyrazoles. The long-range coupling constants (JF-H) of 1-methylpyrazoles and the chemical shifts of trifluoromethyl groups in the 19F NMR spectra can be used for the determination of regio-isomeric structures of mono(trifluoromethyl)-substituted pyrazoles. 2-(Het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines with two trifluoromethyl substituents afford the mixtures of cis- and trans-azopyrazoles in the reactions with hydrazines. \\\\Expert2\\nbo\\Journal of Fluorine Chemistry\\2005, v.126, p.1230.pdf |