Sodium Hydroxide → 1-[5-(3,5-Dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-1h-pyrazole-3-carboxylic acid

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Reaction Steps

To a solution of methyl ester of example 18.1 (408 mg) in 5 ml THF:water (4:1) was added sodium hydroxide (60 mg). The reaction was stirred 2 hours at room temperature before evaporation of the solvent in vacuo. The aqueous layer was extracted with ethyl acetate before being acidified. It was then extracted several times with ethyl acetate. The combined organic layers were dried over sodium sulfate and concentrated to afford the title acid (369 mg) as a yellowish solid. 1H-NMR (CDCl3, 400 MHz): 8.20 (s, 1H), 7.50 (m, 2H), 7.45 (m, 1H), 7.05 (s, 1H), 4.45 (d, 1H), 4.10 (d, 1H).

Provenance & Evidence