反应详情

A mixture of sodium acetate (1 g), absolute chloroform (30 ml), formaldehyde-diethylacetal (30 ml, 0.24 mol), phosphoryl chloride (3.8 ml, 0.04 mol), and 1β-methyl-androst-4-ene-3,17-dione (0.811 g, 2.7 mmol) was stirred at reflux for about 7 hours, i.e. until the starting material had disappeared. The suspension was allowed to cool and under vigorous stirring a saturated sodium carbonate solution was added dropwise until the pH of the aqueous layer became alkaline (~1 hour). The organic layer was separated, neutralized with water, and dried with sodium sulfate. After concentration under reduced pressure the oily residue was purified by chromatography on silica gel using hexane/ethylacetate as eluent. Thus the pure 1β-methyl-6-methylenandrost-4-ene-3,17-dione was obtained in 60% yield (0.195 g); I.R. (KBr): 3100 (6=CH2), 1735 (17-oxo), 1680 (3-oxo), 1630, 1660 cm-1 (Δ4 and 6=CH2).

1. temperatureat reflux for about 7 hours
2. temperatureto cool
3. additionwas added dropwise until the pH of the aqueous layer
4. custom(~1 hour)
5. customThe organic layer was separated
6. dry with materialdried with sodium sulfate
7. concentrationAfter concentration under reduced pressure the oily residue
8. customwas purified by chromatography on silica gel