Compounds of the formula ##STR00001## wherein: Y' is O or S, W' is ##STR00002## optionally substituted, Z' is selected from the group consisting of ##STR00003## wherein Q' is OR.sup.7 and R.sup.7 is C.sub.1-3alkyleneC.sub.3-8heterocycloalkyl useful in the treatment of diseases and conditions related to DNA damage or lesions in DNA replication are disclosed. Methods of making the compounds, and their use as therapeutic agents, for example, in treating cancer and other diseases characterized by defects in DNA replication, chromosome segregation, or cell division also are disclosed.