Synthesis of some trifluoromethyl substituted 1-methylpyrazoles
作者:James W. Pavlik、Theppawut Israsena Na Ayudhya、Supawan Tantayanon
DOI:10.1002/jhet.5570400619
日期:2003.11
reaction of β-alkoxyvinyl trifluoromethyl ketones 1a-c with methylhydrazine (2) in absolute ethanol are the 3-(trifluoromethyl)-substituted-1-methylpyrazoles 3a-3c with lesser amounts of the 5-(trifluoromethyl)-substituted products 4a-4c and 5a-5c. Carrying out the reaction in non-polar, aprotic solvents can further enhance the regioselectivity favoring the 3- (trifluoromethyl) -substituted isomers.
A Convenient Method to Obtain 4,5-Dihydro-<i>1H</i>-Methylpyrazoles by A Ring Transformation Reaction
作者:Helio Gauze Bonacorso、Arci Dirceu Wastowski、Nilo Zanatta、Marcos Antonio Pinto Martins
DOI:10.1080/00397910008087174
日期:2000.4
Abstract A convenientmethod for the synthesis of alkyl[aryl]-substituted 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-methylpyrazole (2) from a new ring transformation reaction of alkyl[aryl]-substituted-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-pyrazolethiocarboxyamide (1) with methylhydrazine in THF, and the thermal dehydration of 2, are reported.