Tetrahydrofuran → 5-Chloro-3-(4,4-difluorocyclohexylmethyl)-2-trifluoromethylimidazo[1,2-a]pyridine-7-carboxylic acid

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Reaction Steps

Ethyl 5-chloro-3-(4,4-difluorocyclohexylmethyl)-2-trifluoromethylimidazo[1,2-a]pyridine-7-carboxylate (62 mg, 0.146 mmol) obtained in step 2 was suspended in a mixed solvent of THF (2.0 mL) and water (2.0 mL), and the suspension was stirred under heat and reflux for 3 hours after adding sodium hydroxide (29 mg, 0.730 mmol). The reaction mixture was allowed to cool to room temperature, and the solvent was then evaporated under reduced pressure. The residue was extracted with water after adding chloroform. Following neutralization with 1 mol/L hydrochloric acid, the solvent was evaporated under reduced pressure. After adding a mixed solution of chloroform/methanol=4/1 to the residue, the insoluble matter was removed by filtration. The filtrate solvent was evaporated under reduced pressure to give a crude product of 5-chloro-3-(4,4-difluorocyclohexylmethyl)-2-trifluoromethylimidazo[1,2-a]pyridine-7-carboxylic acid (66 mg).

Provenance & Evidence