Water → 2-[4-[N-(tert-butoxycarbonyl)-N-methoxymethylamino]-3-fluorophenyl]-6,8-difluoro-5-(4-methyl-3-pentenylamino)-4H-1-benzopyran-4-one

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Reaction Steps

2.70 g (6.00 mmol) of the above 5-amino-2-[4-[N-(tert-butoxycarbonyl)-N-methoxymethylamino]-3-fluorophenyl]-6,8-difluoro-4H-1-benzopyran-4-one was dissolved in 60 mL of dimethylformamide under argon atmosphere, 480 mg (12.0 mmol) of sodium hydride (60% oil dispersion) and 4.0 mL (30 mmol) of 5-bromo-2-methyl-2-pentene were added under ice-cooling and the mixture was stirred at room temperature for 18 hours. The reaction solution was cooled on ice, water was added and the mixture was extracted twice with ethyl acetate. The organic layer was washed twice with water and once with an aqueous saturated solution of sodium chloride and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure and the residue was purified by silica gel column chromatography (chloroform:acetonitrile=30:1) to give 1.21 g of 2-[4-[N-(tert-butoxycarbonyl)-N-methoxymethylamino]-3-fluorophenyl]-6,8-difluoro-5-(4-methyl-3-pentenylamino)-4H-1-benzopyran-4-one (yield: 38%).

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