Hypoxia activated prodrugs of a 9-aza-anthrapyrazole derivative that has promising anticancer activity.

Mono- and bis-N-oxides of a 9-aza-anthrapyrazole derivative having two 2-(dimethylamino)ethyl appendages were prepared by using a mild oxaziridine reagent. Biochemical and cell culture assays indicate that the bis-oxide is an inactive prodrug that readily converts to the active parent molecule under hypoxic conditions that are analogous to those present within certain tumors.