Methylhydrazine → 1,5-Dimethyl-3-(trifluoromethyl)pyrazole

Participants

Reaction Steps

Into 100 ml of an ethanolic solution of 25 g (0.16 mol) of trifluoroacetylacetone, there was added dropwise 7.4 g (0.16 mol) of methylhydrazine. After stirring at room temperature for 3 hours, the mixture was left to stand overnight and the solvent was evaporated to give 19.2 g of 1,5-dimethyl-3-trifluoromethylpyrazole as an oil. Following then the procedures as Reference example 1, this product was allowed to react with chlorosulfonic acid and then with thionyl chloride to obtain 29 g of 1,5-dimethyl-3-trifluoromethylpyrazole-4-sulfonyl-chloride, which was in turn reacted with aqueous ammonia (28%) in tetrahydrofuran to give 21.5 g of 1,5-dimethyl-3-trifluoromethylpyrazole-4-sulfonamide melting at 204°-206° C.

Provenance & Evidence