Diaza- and triazachrysenes: potent topoisomerase-targeting agents with exceptional antitumor activity against the human tumor xenograft, MDA-MB-435

Several 5,12-diazachrysen-6-ones and 5,6,11-triazachrysen-12-ones were synthesized with varied substituents at the 5- or 11-position, respectively. Each compound was evaluated for its potential to stabilize the cleavable complex formed with TOP1 and DNA. Two analogues with very potent TOP1-targeting activity, 3a and 4a, exhibited cytotoxic activity with IC50 values at or below 2 nM against RPMI8402. Compound 3a was active in vivo by either ip or po administration in the human tumor xenograft athymic nude mice model.