24*244DIFLUOROO255HYDROXYCHOLESTENE DERIVATIVE OR ITS HYDROXYYPROTECTED DERIVATIVE AND ITS PREPARATION

摘要

NEW MATERIAL:24,24-Difluoro-25-hydroxycholestenes of formula I (R1, R2 are H or hydroxyl-protecting groups; the dotted line represents single or double bond) or their hydroxyl-protected derivatives. EXAMPLE:3beta-Acetoxy-24,24-difluorocholest-5-ene-25-ol. USE:Synthetic intermediates of 24,24-difluoro-25-hydroxy vitamin D3 that is expected to show the same pharmaceutical activity as that of compounds of vitamin D3 series. PREPARATION:3beta-Hydroxy-24,24-difluoro-27-norcholestene-25-on of formula II or its hydroxyl-protected derivative is made to react with methylmagnesium halide in an aprotonic inert solvent by a conventional method to give the compound of formula I.