Ethyl {[(5-hydroxy-2-{[1-(4-{4-[(methoxymethoxy)methyl]benzyl}phenyl)piperidin-4-yl]methyl}-6-methylpyrimidin-4-yl)carbonyl]amino}acetate (1.1 g, 1.9 mmol) was dissolved in ethyl acetate (14 mL), and a solution of hydrogen chloride in dioxane (4 M, 7 mL, 28 mmol) was added at room temperature, followed by stirring at the same temperature for 12 hours. A saturated aqueous sodium hydrogencarbonate solution was added to the reaction solution, followed by extraction with ethyl acetate, and subsequently the organic layer was dried over anhydrous sodium sulfate. After the solvent was distilled off under reduced pressure, the resulting residue was purified by chromatography on a silica gel column (Moritex Corporation, elution solvent: hexane/ethyl acetate), and a fraction corresponding to the Rf value=0.60 (hexane/ethyl acetate=1/1) by thin layer chromatography was concentrated under reduced pressure to afford the title compound (0.74 g, 1.3 mmol) as a yellow oil (yield 69%).
