Methanol → 4-chloro-1-(difluoromethyl)-1H-pyrazole-3-carboxylic acid

Participants

Reaction Steps

A solution of 4-chloro-1-difluoromethyl-1H-pyrazole-3-carboxylic acid methyl ester (540 mg, 2.6 mmol) in tetrahydrofuran (18 ml) was treated at 23° C. with a solution of lithium hydroxide (135 mg, 5.6 mmol) in a 1:1-mixture of water and methanol (12 ml). After 1 hour the reaction was complete, and the solvents were evaporated at reduced pressure. The residue was partitioned between 2 M aqueous hydrochloric acid and ethyl acetate. The organic layer was dried, evaporated, the residue was triturated with pentane and the solid was dried to give the title compound (477 mg) as a white solid. MS (ISP): m/z=195.0 [M−H]−.

Provenance & Evidence