828 mg (1.97 mmol) of 5-amino-2-[4-[N-(tert-butoxycarbonyl)-N-methylamino]-3-fluorophenyl]-6,8-difluoro-4H-1-benzopyran-4-one obtained in Example 76 was dissolved in 40 ml of dimethylformamide under argon atmosphere, 160 mg of sodium hydride (60% oil dispersion) and 0.53 ml of 6-bromo-1-hexene were added under ice-cooling and the mixture was stirred at room temperature for 2 hours. Additional 80 mg of sodium hydride (60% oil dispersion) and 0.27 ml of 6-bromo-1-hexene were added and the mixture was stirred for additional 1.5 hours. Art aqueous saturated solution of ammonium chloride was added to the reaction solution and the mixture was extracted three times with ethyl acetate. The organic layer was washed with an aqueous saturated solution of sodium chloride and dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=8:1) to give 315 mg (32%) of 2-[4-[N-(tert-butoxycarbonyl)-N-methylamino]-3-fluorophenyl]-6,8-difluoro-5-(5-hexenylamino)-4H-1-benzopyran-4-one.
