p-Toluenesulfonic acid → 3alpha-Hydroxy-17beta-methoxycarbonyl-5alpha-androst-1-en-11-one

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Reaction Steps

A solution of 2β-bromo-3α-hydroxy-17β-methoxycarbonyl-5α-androstan-11-one. (3.48g.,), dihydropyran (8 ml.) and p-toluenesulphonic acid (60 mg.) in benzene (150 ml.) was stirred at room temperature for 15 minutes before being washed with aqueous 10% sodium bicarbonate and water. The benzene solution was dried and evaporated to give a gum which was dissolved in dimethylacetamide (120 ml.). After the addition of anhydrous lithium bromide (14.4g.) and calcium carbonate (11.2g.) the mixture was heated (100°) for 6 hr. Cooling, dilution with chloroform and filtration gave a solution which was washed with water, dried, filtered and evaporated. The residue was dissolved in methanol (200 ml.) containing aqueous 2N hydrochloric acid (1 ml.) After 4 hr. the methanol was removed by evaporation and chloroform added. This solution, after being washed with aqueous 10% sodium bicarbonate and water, was dried, filtered and evaporated to an oil. The addition of ether resulted in crystallisation of the title compound (1.125g.); m.p. 172°-175°; [α]D + 40°, (c 0.7).

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