The mixture of tert-butyl (2,5-dichloropyridin-3-yl)carbamate (7.0 g), 4-(benzyloxy)aniline (7.95 g), 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (1.231 g), Pd2(dba)3 (0.974 g) and sodium tert-butoxide (3.58 g) in toluene (160 ml)-2-propanol (40.0 mL) was stirred at 100° C. under Ar overnight. The reaction mixture was concentrated in vacuo. The residue was purified by column chromatography (silica gel, eluted with 0%-100% EtOAc in hexane) to give intermediate. To the intermediate in DMF (100 mL) were added NaH (3.19 g) and ethyl iodide (20.75 g). The mixture was stirred at room temperature under a dry atmosphere (CaCl2 tube) for 1 h. The reaction mixture was diluted with MeOH and concentrated in vacuo. The residue was purified by column chromatography (NH silica gel, eluted with 0%-50% EtOAc in hexane) to give 3-[4-(benzyloxy)phenyl]-6-chloro-1-ethyl-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (2 g) as a colorless solid.
