反应详情

A mixture of sodium acetate (1 g), absolute chloroform (30 ml), formaldehyde diethyl acetal (30 ml, 0.24 mol), phosphoryl chloride (3.8 ml, 0.04 mol), and 1β,7α-dimethyl-16α-fluoroandrost-4-ene-3,17-dione (0.896 g, 2.7 mmol) is stirred at reflux for about 5 hrs, i.e. until the starting material has disappeared. The suspension is allowed to cool and under vigorous stirring a saturated sodium carbonate solution is added dropwise until the pH of the aqueous layer becomes alkaline. The organic layer is separated, washed to neutrality with water, and dried with sodium sulfate. After concentration under reduced pressure the oily residue is purified by chromatography on silica gel using hexane/ethyl acetate as eluant. Thus the pure 1β,7α-dimethyl-16α-fluoro-6-methylenandrost-4-ene-3,17-dione is obtained in 60% yield (0.56 g).

1. temperatureat reflux for about 5 hrs
2. temperatureto cool
3. additionis added dropwise until the pH of the aqueous layer
4. customThe organic layer is separated
5. washwashed
6. dry with materialdried with sodium sulfate
7. concentrationAfter concentration under reduced pressure the oily residue
8. customis purified by chromatography on silica gel