5 ml of 4 N hydrogen chloride in dioxane and 2.5 ml of dioxane were added to 500 mg (0.854 mmol) of 3-[(2S)-3-[4-[1-(benzyloxycarbonyl)-4-piperidyloxy]phenyl]-2-(4-iodobenzenesulfonylamino)propoxy]benzonitrile. The mixture was stirred at room temperature for 24 hours, and the solvent was distilled off under reduced pressure, and the resulting residue was dissolved in 8 ml of DMF, and 0.49 ml (2.56 mmol) of di-isopropylethylamine and 398 mg (1.28 mmol) of 2-(benzyloxycarbonyl)benzene sulfonyl chloride were added thereto at 0° C. The mixture was stirred for 1 hour, then allowed to reach room temperature, and stirred for additional 24 hours. The reaction solution was extracted with ethyl acetate, washed with water, 1 N hydrogen chloride and saturated saline, and dried over powdery magnesium sulfate. The solvent was distilled off, and the resulting residue was purified by silica gel column chromatography to obtain the title compound.
