反应详情

Chloromethyl acetate (2.2 ml) was added to a stirred solution of 3-bromo-4-oxo-6-phenyl-4H-pyran-2-carboxylic acid (5.9 g) and triethylamine (2.9 ml) in dry DMF (40 ml). The solution was heated at 70°-80° C. for 3 hours, then poured on to ice-water and extracted with ethyl acetate. The extract was washed with sodium bicarbonate solution, dried and evaporated, and the residue was crystallised from ethanol-water. The crude product was purified by chromatography on silica-gel and recrystallisation from ethyl acetate-petroleum ether 60°-80° C. gave the title product as white needles (mp 121° C.).

1. temperatureThe solution was heated at 70°-80° C. for 3 hours
2. extractionextracted with ethyl acetate
3. washThe extract was washed with sodium bicarbonate solution
4. customdried
5. customevaporated
6. customthe residue was crystallised from ethanol-water
7. customThe crude product was purified by chromatography on silica-gel and recrystallisation from ethyl acetate-petroleum ether 60°-80° C.