Synthesis and in vitro antitumor activity of ring C and D-substituted phenanthrolin-7-one derivatives, analogues of the marine pyridoacridine alkaloids ascididemin and meridine.

A series of cycle C and D-substituted phenanthrolin-7-ones, analogues of the marine pyridoacridines meridine and ascididemin have been synthesized on the basis of Diels-Alder reactions involving quinoline-5,8-dione and 2- (or un)-substituted-N,N-dimethylhydrazones. All the compounds were evaluated for in vitro cytotoxic activity against 12 distinct human cancer cell lines. They all exhibit cytotoxic activity with IC(50) values at least of micromolar order.