Hydrochloric Acid → 2-(1-{[3,5-Bis(difluoromethyl)-1H-pyrazol-1-yl]acetyl}piperidin-4-yl)-1,3-thiazole-4-carboxylic acid

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Reaction Steps

Ethyl 2-(1-{[3,5-bis(difluoromethyl)-1H-pyrazol-1-yl]acetyl}piperidin-4-yl)-1,3-thiazole-4-carboxylate (IV-1, 13.3 g) is dissolved in tetrahydrofuran (80 ml). LiOH monohydrate (1.86 g) dissolved in water (20 ml) is then added. After 3 hours, water is added, the pH is adjusted to 2-3 with dilute hydrochloric acid (1M), the mixture is then extracted with ethyl acetate and the combined organic phases are dried with sodium sulfate. The solid is filtered off and the solvent is removed by distillation. This gives 2-(1-{[3,5-bis(difluoromethyl)-1H-pyrazol-1-yl]acetyl}piperidin-4-yl)-1,3-thiazole-4-carboxylic acid (11.7 g, 94%).

Provenance & Evidence