反应详情

6.3 g of the product obtained in Stage A above, 30 cm3 of trifluoroacetic anhydride and 6.3 g of sodium trifluoro-acetate are agitated under reflux for 12 hours. The mixture is evaporated to dryness, cooled down and the residue is taken up immediately in 120 cm3 of a 5% solution of sodium bicarbonate then in 350 cm3 of methanol. Agitation is carried out for 3 hours at ambient temperature, the mixture is concentrated to a reduced volume at 30° C. then extracted with methylene chloride, the extracts are dried and evaporated. The residue is chromatographed on silica (eluant: ethyl acetate - hexane (8-2)) after crystallization from ethanol, 2.1 g of desired product, M.p.=170-172° C., and 0.3 g of the corresponding delta-3,4 derivative are obtained.

1. temperatureunder reflux for 12 hours
2. customThe mixture is evaporated to dryness
3. temperaturecooled down
4. concentrationthe mixture is concentrated to a reduced volume at 30° C.
5. extractionthen extracted with methylene chloride
6. customthe extracts are dried
7. customevaporated
8. customThe residue is chromatographed on silica (eluant: ethyl acetate - hexane (8-2))
9. customafter crystallization from ethanol, 2.1 g of desired product, M.p.=170-172° C., and 0.3 g of the corresponding delta-3,4 derivative
10. customare obtained