Trimethyl orthoformate → 3-Ethylenedioxy-11beta-fluoro-7alpha-methylestr-5(10)-en-17beta-ol

Participants

Reaction Steps

3.63 ml of ethylene glycol and 1.82 ml of trimethyl orthoformate and 23.6 ml of para-toluenesulfonic acid hydrate were added to a solution of 500 mg of 11β-fluoro-17β-hydroxy-7α-methyl-estr-4-en-3-one (I) in 6.35 ml of dichloromethane. The reaction mixture was stirred for 20 hours at room temperature. Then, it was mixed with sodium carbonate solution, diluted with ethyl acetate, washed neutral, dried on sodium sulfate, concentrated by evaporation in a vacuum and chromatographed on silica gel with hexane/ethyl acetate. 170 mg of 3-ethylenedioxy-11β-fluoro-7α-methylestr-5(10)-en-17β-ol (C), which contained portions of double-bond-isomeric 3-ethylenedioxy-11β-fluoro-7α-methylestr-5-en-17β-ol (C), was obtained.

Provenance & Evidence