Sodium Hydroxide → 1-Phenyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid

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Reaction Steps

A mixture of 1-phenyl-3-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (1.25 g, 4.4 mmol) and 1N aqueous sodium hydroxide solution (17.3 mL) in methanol (20 mL) was stirred at room temperature overnight. The reaction mixture was concentrated and acidified to pH˜1 with 1N aqueous hydrochloric acid. The slurry was extracted with methylene chloride and the combined organic layers were washed with saturated sodium chloride and dried over sodium sulfate. Filtration and concentration gave 1-phenyl-3-trifluoromethyl-1H-pyrazole-4-carboxylic acid (1 g, 89% yield) as an off-white solid, which was directly used in the next step without further purification. LCMS calcd for C11H7F3N2O2 (m/e) 256, obsd 255 (M−H).

Provenance & Evidence