p-Toluenesulfonic acid → 7alpha-Methylestr-5-ene-3,11,17-trione

Participants

Reaction Steps

A mixture of 7α-methylestr-4-ene-3,11,17-trione (B, Example 23, 4.1 g), methylene chloride (50 ml), ethylene glycol (31 ml), triethylorthoformate (14 ml) and p-TSA (41 mg) are refluxed for 3 hours. The mixture is then cooled and washed with bicarbonate and water, then dried to a solid. NMR shows a mixture of Δ5 (10) and Δ5 isomers. The product is used without further purification.

Provenance & Evidence