| abstract |
The present invention provides a compound of formula (I or II) below and a pharmaceutically acceptable salt thereof, and the present invention also provides a pharmaceutical composition comprising said compound (I or II), said compound (I or II) ), Intermediates useful in the preparation of the compound (I or II), and therapeutic methods for treating cancer and other topoisomerase-related conditions using the compound (I or II). [Chemical 1] [Wherein the bond represented by --- is a single bond or a double bond; R 1 to R 5 , X and Y have the meanings specified in the specification] |