Under an argon stream, a mixture of 6-bromo-2-(3-methoxyphenyl)-1H-imidazo[4,5-b]pyridine (Compound of Reference Example 2) (21.3 g), phenylboric acid (22.2 g), tetrakis(triphenylphosphine)palladium(0) (7.60 g), 2 M sodium carbonate (175 ml), toluene (525 ml) and tetrahydrofuran (175 ml) was stirred at 90° C. for 24 hours. The reaction mixture was distributed into ethyl acetate-tetrahydrofuran (3:1, v/v) and water. The organic layer was washed with water, dried over MgSO4. The solvent was distilled off under reduced pressure, and the resulting crystals were collected by filtration to obtain 2-(3-methoxyphenyl)-6-phenyl-1H-imidazo[4,5-b]pyridine (14.0 g, 66%). The crystals were recrystallized from chloroform-methanol.
