| 摘要 |
<p>PURPOSE:24-Oxocholestrol is reduced to give a racemic mixture of hydroxy derivative, which is separated, one of the epimers is collected and the other is oxidized for reuse, thus producing the titled compound used as an intermediate of medicines in high efficiency. CONSTITUTION:24-Oxocholesterol of formulaI(R is protecting group for hydroxyl) is reduced, preferably with a borohydride or aluminum hydride, to form a racemic mixture of 24(R) and 24(S)-hydroxycholesterol of formula II. Then, the mixture is separated into two epimers and one of them is collected, the other is oxidized, preferably by oxygen oxidation, to give 24-oxocholesterol of formulaI, which is used again.</p> |
