Water → 2-(4-Amino-3-fluorophenyl)-6,8-difluoro-5-(4-methyl-3-pentenylamino)-4H-1-benzopyran-4-one

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Reaction Steps

1.03 g (1.94 mmol) of the above 2-[4-[N-(tert-butoxycarbonyl)-N-methoxymethylamino]-3-fluorophenyl]-6,8-difluoro-5-(4-methyl-3-pentenylamino)-4H-1-benzopyran-4-one was dissolved in 80 mL of ethanol, 20 mL of 50% sulfuric acid was added and the mixture was stirred at room temperature for 18 hours. Water was added to the reaction solution and the mixture was extracted twice with ethyl acetate. The organic layer was washed once with an aqueous saturated solution of sodium bicarbonate, once 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 (n-hexane:ethyl acetate=5:2-2:1) to give 520 mg of Compound 137 (yield: 69%).

Provenance & Evidence