Aza and diaza bioisosteric anthracene-9,10-diones as antitumor agents.

: Synthetic routes to aza and diaza bioisosteres related to the anthracene-9,10-dione, mitoxantrone, have been developed. The antitumor properties of these chemotypes are compared with those exhibited by the corresponding carbocyclic analogues. The sensitivity of the expressed cytotoxicities on the position(s) of the nitrogen atom(s) are discussed in terms of potential cellular targets. Several analogues show potential for clinical evaluations.