Quinoxaline 1, 4-dioxide (4) is the historical prototype for modern heterocyclic N-oxide antitumor agents such as 3-amino-1, 2, 4-benzotriazine 1, 4-dioxide (tirapazamine, 1) and 3- amino-2-quinoxalinecarbonitrile 1, 4-dioxide (11). Early experiments in bacterial cell lines suggested that enzymatic, single-electron reduction of quinoxaline 1, 4-dioxides under low- oxygen (hypoxic) conditions leads to DNA damage. Here the ability of quinoxaline 1, 4- ...
