A solution of the compound (421 mg, 0.8 mmol) obtained in Example 14-5), 3-pyridylboronic acid (197 mg, 1.6 mmol), tetrakis(triphenylphosphine)palladium(0) (185 mg, 0.16 mmol), and potassium carbonate (221 mg, 1.6 mmol) in dimethoxyethane (3.2 mL) and water (0.8 mL) was stirred at 100° C. for 6 h. The reaction mixture was cooled to room temperature, saturated aqueous sodium hydrogencarbonate was added to the reaction mixture, the mixture was extracted with dichloromethane, and the organic layer was washed with saturated sodium chloride solution and dried with anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (Isco Combiflash, 40 g, methanol:ethyl acetate=0:100 to 20:80, gradient) to obtain the title compound (344 mg, 82%) as a colorless solid.
