The compound (120 mg) obtained in Example 47-3 was dissolved in methanol (5.0 ml) and then added with the compound (57.0 mg) obtained in Example 91-1 and sodium cyanoborohydride (18.0 mg). Then, the solution was adjusted to pH 5 with acetic acid and then stirred at room temperature for 2 days. After completion of the reaction, a 1 mol/l sodium hydroxide aqueous solution was added to the reaction solution, followed by separation/extraction with chloroform. The organic layer was dried with anhydrous sodium sulfate and the solvent was then distilled off. The residue was purified through silica gel column chromatography (chloroform/methanol) and then treated with hydrochloric acid, thereby obtaining hydrochloride (201 mg) of the subject compound as a white solid.
