Oxalic Acid → 17-Difluoromethylene-estra-1,3,5(10)-trien-3-ol

Participants

Reaction Steps

1.3 g of crude 17-difluoromethylene-3-(tetrahydro-pyran-2-yl-oxy)-estra-1,3,5(10)-triene in 30 ml of methanol and 3 ml of water are suspended with 1.3 g of oxalic acid for 1 hour at a bath temperature of 100° C. Then, it is added to water, extracted three times with dichloromethane, washed neutral, dried on sodium sulfate and evaporated to dryness in a vacuum. 1.0 g of crude 17-difluoromethylene-estra-1,3,5(10)-trien-3-ol, which is chromatographed on silica gel with hexane/ethyl acetate, is obtained. 480 mg of pure 17-difluoromethylene-estra-1,3,5(10)-trien-3-ol is obtained as colorless crystals with a melting point of 154-156° C.

Provenance & Evidence