Sodium Hydroxide → 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylic acid methyl ester (2.0 g, 10.19 mmol) in methanol (6.8 mL) cooled to 0° C. was treated dropwise with a 4N aqueous sodium hydroxide solution (5.1 mL, 20.4 mmol). The reaction was allowed to slowly warm to 25° C. The reaction was stirred at 25° C. overnight. At this time, the reaction was concentrated in vacuo to remove methanol. The residue was diluted with water (25 mL) and was then extracted with ethyl acetate (1×25 mL). The aqueous layer was then acidified to pH=1 with a 3N aqueous hydrochloric acid solution. The resulting precipitate was collected by filtration, washed with water and hexanes, and then dried in vacuo to afford 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylic acid (1.43 g, 78%) as a white solid.

Provenance & Evidence