| 摘要 |
<p>PURPOSE:The reduction reaction of a 24-oxo-DELTA<25>-cholesterol is conducted in an inert organic solvent in the presence of a specific optically active compound to produce the titled compound in high yield, which is used as an intermediate of 24-hydroxycholecalciferol. CONSTITUTION:A compound of formula I (R1 is H, protecting group; R2 is H, hydroxyl, protected hydroxyl) is reduced with lithium aluminum hydride in an inert solvent such as tetrahydrofuran in the presence of optically active 2,2'-dihydroxy- 1,1'-binaphthyl and a lower aliphatic alcohol such as methanol to produce 24(R) or 24(S)-hydroxycholesterol. The reaction temperature is -200-50 deg.C. The starting material, the compound of formula I, is novel and obtained by reaction of 3beta- tetrahydropyranyloxy-chol-5-ene-24-al derived from cholenic acid with propenylmagnesium bromide, followed by oxidation.</p> |
