Ethanol → 5-{[Cyclohexyl(5-fluoro-3-methyl-1-benzofuran-2-yl)methyl]amino}pyridine-2-carboxylic acid

To a mixture of methyl 5-{[cyclohexyl(5-fluoro-3-methyl-1-benzofuran-2-yl)methyl]amino}pyridine-2-carboxylate (909 mg) synthesized above, ethanol (20 mL) and tetrahydrofuran (20 mL) was added 1N aqueous sodium hydroxide solution (20 mL), and the mixture was stirred with heating under reflux for 5 hr, and concentrated under reduced pressure. 1N Hydrochloric acid (20 mL) was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was washed with hexane to give the title object compound (751 mg, 86%) as a pale-brown solid.