摘要 |
The invention provides compounds of formula I or formula II: wherein: the bond represented by - is a single bond or a double bond, and R<SUB>1</SUB>-R<SUB>5</SUB>, X, and Y have any of the meanings defined in the specification and their pharmaceutically acceptable salts. The invention also provides pharmaceutical compositions comprising a compound of formula I or II, processes for preparing compounds of formula I or II, intermediates useful for preparing compounds of formula I or II, and therapeutic methods for treating cancer and other topoisomerase related conditions using compounds of formula I or II.
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