反应详情

30 g of 1,3-dibromopropane was added dropwise at ambient temperature to a suspension of 30 g of sodium 3-methyl-4-oxo-2-phenyl-4H-1-benzopyran-8-carboxylate in 150 ml of dimethylformamide and 35 ml of water. The reaction mixture was stirred at ambient temperature for 5 days. 100 ml of water were added and stirring was continued for another 15 minutes. The precipitate was filtered by suction, washed with water and purified by flash chromatography on silica gel, eluting with chloroform:ethyl acetate 95:5. The collected fractions were evaporated to dryness in vacuo and the residue was recrystallized from ethanol to give 27.7 g of the title compound, melting point 114°-115° C.

1. stirringstirring
2. waitwas continued for another 15 minutes
3. filtrationThe precipitate was filtered by suction
4. washwashed with water
5. custompurified by flash chromatography on silica gel
6. washeluting with chloroform:ethyl acetate 95:5
7. customThe collected fractions were evaporated to dryness in vacuo
8. customthe residue was recrystallized from ethanol