| 摘要 |
<p>A process for preparing very pure ursodeoxycholic acid starting from cholic acid (1) by:
<UnorderedLists id="ula01" listStyle="none"><ListItem>a) selectively oxidising it to 3 alpha, 12 alpha-dihydroxy-7-ketocholanic acid (II)</ListItem><ListItem>b) reducing acid (II) to 3 alpha, 7 beta, 12 alpha-trihydroxycholanic acid (III)</ListItem><ListItem>c) oxidising a 3,7-ester of acid (III) to 3 alpha, 7 beta-dihydroxy-12-keto-5-beta-cholanic acid (IV) by treatment with hypochlorite followed by hydrolysis
<UnorderedLists id="ula02" listStyle="none"><ListItem>d) preparing the tris-trimethylsilyl derivative of acid (IV)</ListItem><ListItem>e) eliminating the trimethylsilyl groups</ListItem><ListItem>f) reducing the very pure acid (IV) by the Wolff-Kishner method to ursodeoxycholic acid.</ListItem></UnorderedLists></ListItem></UnorderedLists></p><p>Alternatively, the Wolff-Kishner method can be applied directly to the tris-trimethylsilyl derivative, and the trimethylsilyl groups can be eliminated from the final product.</p> |
