A solution of the compound prepared in Example 17 in dichloromethane (1.8 mL) was dropped to a solution of the compound (100 mg) prepared in Example 16 in dichloromethane (1.8 mL). Pyridine (0.057 mL) was added to the reaction mixture, which was stirred for 1 hour at room temperature. The reaction mixture dissolved to water was extracted with ethyl acetate. The organic layer was sequentially washed with diluted hydrochloric acid, saturated sodium hydrogencarbonate solution, and saturated brine solution and was dried by anhydrous magnesium sulphate. The title compound (164 mg) having the following physical data was obtained by purifying the residue obtained by removing the solvent by silica gel column chromatography (n-hexane:ethyl acetate=4:1). TLC: Rf 0.41 (n-hexane:ethyl acetate=2:1).
