Sodium Bicarbonate → 5-Amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-propanoylpyrazole

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Reaction Steps

To a stirred solution of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-(prop-1-ynyl)pyrazole (2.1 g) in acetonitrile (40 ml) was added p-toluenesulphonic acid monohydrate (292 g) and the mixture was stirred at room temperature for 1 hour. p-Toluenesulphonic acid monohydrate (1 g) was then added and stirring continued overnight. Acetonitrile (20 ml) was added p-toluenesulphonic acid monohydrate (1 g) were added and stirring continued for 1 hour and then the reaction mixture was poured into saturated aqueous sodium hydrogen carbonate solution (500 ml) and extracted twice with ether (100 ml). The organic layer was separated, washed with brine (100 ml), dried (Na2SO4) and evaporated. The residue was purified by column chromatography on silica gel (70 g) eluted with dichloromethane. Combination and evaporation of suitable fractions gave the title compound as a pale brown solid, m.p. 167-169° C.

Provenance & Evidence