Water → 1-(5-Chloro-3-fluoropyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid

Participants

Reaction Steps

To a solution of 1-(5-chloro-3-fluoropyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (1 g) in tetrahydrofuran (5 ml) were added 4 N aqueous solution of sodium hydroxide (5 ml) and water (5 ml), and stirred at room temperature overnight. After completion of the reaction, the organic solvent was evaporated in vacuo, then water and diethyl ether were added thereto, and the aqueous layer was separated. To the aqueous layer was added concentrated hydrochloric acid under ice-cooling to adjust the layer to pH 5, the precipitated solid was collected by filtration, and dried at 60° C. under air blow to give the titled compound (710 mg) as a white solid. MS (ESI) m/z: 256 (M+H)+.

Provenance & Evidence