Hydrochloric Acid → 1-(4-Methoxybenzyl)-3-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid

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Reaction Steps

Add a solution of LiOH (122 mg, 5.03 mmol) in H2O (3 mL) to a stirred solution of ethyl 1-(4-methoxybenzyl)-3-(trifluoromethyl)-1H-pyrazole-4-carboxylate (550 mg, 1.68 mmol) in 1,4-dioxane (10 mL). Stir overnight at ambient temperature. Acidify to pH 5 with 1 N HCl and extract with CH2Cl2 and 2× with 20% iPrOH in CHCl3. Dry the combined organic layers with MgSO4, filter and concentrate under reduced pressure to obtain 140 mg of the title compound as a white solid. Acidify the aqueous layer to pH 2-3 with 1 N HCl, and extract twice with 20% iPrOH in CHCl3. Dry the combined organics over MgSO4, filter, and add the solution to the initially obtained 140 mg white solids. Concentrate to afford the title compound as a white solid (426 mg, 85%). ES/MS m/z 299.0 (M−1).

Provenance & Evidence