Sodium Hydroxide → 3-(difluoromethyl)-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylic acid

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Reaction Steps

A solution of 600 mg (2.20 mmol) of ethyl 3-(difluoromethyl)-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylate in 10 ml of methanol is admixed with 331 mg (3.31 mmol) of 40% strength sodium hydroxide solution and stirred for three hours at room temperature. The reaction mixture is concentrated by evaporation, admixed with water and extracted with diethyl ether. The aqueous phase is acidified with dilute hydrochloric acid and extracted twice with diethyl acetate. The organic phase is dried over sodium sulphate and, after filtration, is concentrated by evaporation. This gives 452 mg of 3-(difluoromethyl)-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylic acid (84%).

Provenance & Evidence