Sodium borohydride → 11beta-Fluoro-7alpha-{5-[2-(4,4,5,5,5-pentafluoropentylthiomethyl)pyrrolidin-1-yl]-pentyl}-estra-1,3,5(10)-triene-3,17beta-diol

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Reaction Steps

500 mg of 11β-fluoro-3-hydroxy-7α-{5-[2-(4,4,5,5,5-pentafluoropentylthiomethyl)-pyrrolidin-1-yl]-pentyl}-estra-1,3,5(10)-trien-17-one in 5 ml of tetrahydrofuran, 2.75 ml of ethanol and 1.1 ml of water, and 100 mg of sodium borohydride is added at a bath temperature of 0° C., and it is stirred for 0.5 hour at room temperature. Then, it is added to water, extracted 3 times with ethyl acetate, washed neutral with saturated common salt solution, dried on sodium sulfate, concentrated by evaporation in a vacuum and chromatographed on silica gel with dichloromethane/methanol. 441.3 mg of 11β-fluoro-7α-{5-[2-(4,4,5,5,5-pentafluoropentylthiomethyl)-pyrrolidin-1-yl]-pentyl}-estra-1,3,5(10)-triene-3,17β-diol is obtained as crystals with a melting point of 174-176° C. [α]D22 =-14.9° (c=0.5% in pyridine).

Provenance & Evidence