To a mixture of 2-[2-(4-{[3-chloro-4-(piperidin-4-yloxy)phenyl]amino}-5H-pyrrolo[3,2-d]pyrimidin-5-yl)ethoxy]ethyl benzoate dihydrochloride (305 mg), 10% aqueous sodium carbonate solution (10 mL), ethyl acetate (15 mL) and tetrahydrofuran (5 mL) was added 2,6-difluorophenyl isocyanate (93 mg) with vigorous stirring. The mixture was stirred at room temperature for 2 hrs, water was added and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure and the obtained residue was dissolved in methanol (8 mL) and tetrahydrofuran (2 mL). 1N Aqueous sodium hydroxide solution (1 mL) was added, and the mixture was stirred at room temperature for 3 hrs. Water was added to the reaction mixture and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure and the obtained residue was subjected to basic silica gel column chromatography (eluent, methanol:ethyl acetate=0:100→15:85). The object fraction was concentrated under reduced pressure. The residue was dissolved in ethyl acetate-ethanol, and 1N hydrochloric acid/ethyl acetate solution (0.5 mL) was added. The solvent was evaporated under reduced pressure and the obtained residue was crystallized from ethanol-ethyl acetate to give the title compound (202 mg) as a white powder.
