| 摘要 |
<p>PURPOSE:To prepare the title compound which is a vitamin D3 derivative having blood Ca level increasing activity, economically, in high yield, by eliminating the hydroxy-protecting groups of a 1alpha,24(S),25-trihydroxycholecalciferol derivative. CONSTITUTION:The objective compound II is prepared by eliminating the OH- protecting groups of the compound I (R1 is acyl; R2 is acyl, trimethylsilyl, H). When the groups are acyl, the elimination can be carried out by decomposing the compound I in an alkaline methanol solvent at -10-+30 deg.C. The starting compound I can be prepared by (1) irradiating a compound III with UV radiation (pref. 260-310nm in wave length) in an inert organic solvent such as hexane, in Ar or N2 atmosphere free of O2, at -20-+80 deg.C, and (2) heating and isomerizing the product.</p> |
