Acetone → 1-(2-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazole-5-carboxylic acid

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Reaction Steps

An aqueous solution of 27.94 g of potassium permanganate in 100 ml of water was added dropwise to a mixture of 18.43 g of 1-(2-chlorophenyl)-5-(2-furyl)-3-trifluoromethyl-1H-pyrazole and 250 ml of acetone with being kept at 40° C. or lower. Then, the mixture was stirred at room temperature for 20 hours. The reaction mixture was filtered through Celite (registered trademark) to obtain a filtrate. The filtrate was adjusted to pH 10-12 by an addition of a 2N aqueous sodium hydroxide solution, and then extracted with ethyl acetate two times. The aqueous layer was adjusted to around pH 3 by an addition of 2 N hydrochloric acid, and then extracted with methyl tert-butyl ether three times. The organic layers were combined, washed with an aqueous saturated sodium chloride solution, dried over magnesium sulfate, and concentrated under reduced pressure to obtain 10.65 g of 1-(2-chlorophenyl)-3-trifluoromethyl-1H-pyrazole-5-carboxylic acid of the formula:

Provenance & Evidence