反应详情

A mixture of 4.5 g of Intermediate XXXIX, 3.9 g of 8-amino-3-methyl-4-oxo-2-phenyl-4H-1-benzopyran, 8.3 g of sodium triacetoxyborohydride and 3.4 ml of acetic acid in 40 ml of 1,2-dichloroethane was stirred for 6 hours at 20°-25° C. 15 ml of 5% aqueous sodium bicarbonate solution was then added, and the mixture was stirred for 10 minutes. The mixture was then made alkaline by addition of 0.5N aqueous sodium hydroxide solution and extracted with dichloromethane. The organic extracts were washed with water and dried on anhydrous sodium sulfate. The solvent was evaporated off in vacuo and the residue was purified by flash chromatography on silica gel, eluting with ethyl acetate: petroleum ether 9:1. The base obtained was dissolved in dichloromethane and 1 equivalent of ethanolic hydrogen chloride was added. After removing the solvent in vacuo, the residue was crystallized from 50% ethanol to give 1.6 g of the title compound, m.p. (140) 151°-153C.

1. stirringthe mixture was stirred for 10 minutes
2. extractionextracted with dichloromethane
3. washThe organic extracts were washed with water
4. dry with materialdried on anhydrous sodium sulfate
5. customThe solvent was evaporated off in vacuo
6. customthe residue was purified by flash chromatography on silica gel
7. washeluting with ethyl acetate: petroleum ether 9:1
8. customThe base obtained
9. customAfter removing the solvent in vacuo
10. customthe residue was crystallized from 50% ethanol