Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10572761 | Journal of Fluorine Chemistry | 2005 | 9 Pages |
Abstract
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 α-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.
Related Topics
Physical Sciences and Engineering
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Authors
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,