Lithium Hydroxide → 1-isopropyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid

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Reaction Steps

A solution of ethyl 1-isopropyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxylate (266 mg, 1.06 mmol) and lithium hydroxide (102 mg, 4.25 mmol) in ethanol:water:dioxane (1:1:1, 6 mL) was warmed to 40° C. and stirred overnight. The mix cooled to RT, diluted with water (25 mL) and washed with ether (20 mL). The aqueous phase made acidic with 3N HCl (pH˜2) and extracted with ethyl acetate (2×15 mL). The combined ethyl acetate layers were washed with brine (20 mL), dried (Na2SO4) and concentrated in vacuo to give 1-isopropyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid (199 mg, 84% yield) as a white solid. MS (ESI) m/z: 223.0.

Provenance & Evidence