Hydrochloric Acid → 2-[1-[[5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl]acetyl]-4-piperidinyl]-4-thiazolecarboxylic acid

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Reaction Steps

To a solution of 2-{1-[2-(5-methyl-3-trifluoromethyl-pyrazol-1-yl)-acetyl]-piperidin-4-yl}-thiazole-4-carboxylic acid ethyl ester (2.67 g, 6.2 mmol) in THF (20 mL) is added aqueous solution of sodium hydroxide (2 M, 4.65 mL, 9.3 mmol) at RT. After stirring 3 h at RT, the reaction mixture is acidified with 2M aqueous solution of HCl until pH 2-3, and the solution is extracted with ethylacetate (20 mL). The aqueous layer is re-extracted with ethylacetate (20 mL) and the combined organic layers are washed with brine (10 mL), dried over sodium sulfate, filtered, and evaporated under reduced pressure to give 2-{1-[2-(5-methyl-3-trifluoromethyl-pyrazol-1-yl)-acetyl]-piperidin-4-yl}-thiazole-4-carboxylic acid (2.33 g, 94%), which can be used in the next step without further purification. 1H-NMR (400 MHz, d6-acetone): δ=1.69-1.82 (m, 1H), 1.87-2.02 (m, 1H), 2.16-2.37 (m, 2H), 2.38 (s, 3H), 2.89-2.99 (m, 1H), 3.38-3.48 (m, 2H), 4.14-4.22 (m, 1H), 4.50-4.69 (m, 1H), 5.20-5.36 (2d, 2H (diastereotopic)), 6.41, (s, 1H), 8.34 (s, 1H). MS: m/z=403 (M+1).

Provenance & Evidence