| 摘要 |
<p>Methods are provided for preparing a compound with a fused ring structure of formula (XIV) which comprises one or more reactions starting from a 21-cyano compound of formula (XVI) where typically: R1 is an amidomethylene group or an acyloxymethylene group; R?5 and R8¿ are independently chosen from -H, -OH or -OCOCH¿2?OH, or R?5 and R8¿ are both keto and the ring A is a p-benzoquinone ring; R?14a and R14b¿ are both -H ozone is -H and the other is -OH, -OCH¿3? or -OCH2CH3, or R?14a and R14b¿ together form a keto group; and R?15 and R18¿ are independently chosen from -H or -OH, or R?5 and R8¿ are both keto and the ring A is a p-benzoquinone ring. In modified starting materials, the 21-cyano group can be replaced by other groups introduced using nucleophilic reagents.</p> |
