255HYDROXYY244OXOCHOLESTEROL DERIVATIVE AND ITS PREPARATION

摘要

NEW MATERIAL:Compounds of formula I (R<1> and R<5> are H, hyroxyl-protecting group; R<2> is H, hydroxyl, protected hydroxyl; R<3> and R<4> are H or incorporate to represent C-C bonds). EXAMPLE:3beta,25-Dihydroxy-24-oxocholest-5-ene. USE:Synthetic intermediates of various kinds of active-type vitamin D3. PREPARATION:24-Oxyocholesterol derivative of formula II is oxidized by introducing 0.5-2 moles, per mole of the compound of formula II, of oxygen in the presence of a basic compound, e.g., sodium t-butoxide, to form a compound of formula III. then, when needed, hydroxyl groups are removed or protected to give the compound of formula I. The reaction temperature is preferably -40-100 deg.C and an organic solvent, e.g., hexane, is advantageously used. The amount of the basic compound used is 0.1-100 moles per mol of the compound of formula II.