Hydrochloric Acid → 5-[2-(Trifluoromethyl)phenyl]-1,2-oxazole-4-carboxylic acid

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Reaction Steps

A mixture of 5-(2-trifluoromethyl-phenyl)-isoxazole-4-carboxylic acid ethyl ester (1.43 g, 5.01 mmol, 1.0 equiv), 6M HCl aqueous solution (34 mL) and acetic acid (20 mL) were heated to reflux for 5.5 hours. After cooling, the mixture was partitioned between water and ethyl acetate and separated. The organic phase was washed sequentially with water and saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, and concentrated under vacuum to give 745 mg (58%) of crude 5-(2-trifluoromethyl-phenyl)-isoxazole-4-carboxylic acid which was used without purification.

Provenance & Evidence