| abstract |
The invention provides compounds of formula I: wherein A, B, W, Y, Z, R<SUB>1</SUB>, R<SUB>3 </SUB>and R<SUB>4 </SUB>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, processes for preparing compounds of formula I, intermediates useful for preparing compounds of formula I, and therapeutic methods for treating cancer using compounds of formula I. |