Oxalic Acid → 17-Difluoromethylene-estra-1,3,5(10),7-tetraen-3-ol

Participants

Reaction Steps

A suspension of 950 mg of 17-difluoromethylene-3-tetrahydropyranyloxy-estra-1,3,5(10),7-tetraene in 20 ml of methanol and 2.0 ml of water is refluxed with 950 mg of oxalic acid for 0.5 hour at a bath temperature of 100° C. Then, it is concentrated by evaporation in a vacuum diluted with ethyl acetate, washed with water, sodium bicarbonate solution as well as with saturated sodium chloride solution, dried on sodium sulfate, concentrated by evaporation in a vacuum and chromatographed on silica gel with hexane/ethyl acetate. 0.6 g of 17-difluoromethylene-estra-1,3,5(10),7-tetraen-3-ol is obtained as colorless crystals with a melting point of 126-129° C., [α]D22 =+163.7° (c=0.505% in pyridine)

Provenance & Evidence