Back to Search
Start Over
Synthesis and the reactions of trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines
- Source :
- Journal of Fluorine Chemistry. 126:1230-1238
- Publication Year :
- 2005
- Publisher :
- Elsevier BV, 2005.
-
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.
Details
- ISSN :
- 00221139
- Volume :
- 126
- Database :
- OpenAIRE
- Journal :
- Journal of Fluorine Chemistry
- Accession number :
- edsair.doi.dedup.....e9075dc3828231fbca7b505e22103f06