Synthesis and evaluation of C-ring aromatized analogues of phenanthridone alkaloids.

Phenanthridone alkaloids are envisaged as an attractive lead for the development of anticancer agents. We have prepared a series of aromatized analogues on the basis of the structure of this class of alkaloids with the hope of finding the simplified compounds with comparable activities. The obtained analogues were evaluated for their cytotoxic effect against several cancer cell lines and found to be virtually inactive. These observations together with molecular modeling studies strongly suggest that the stereochemistries of hydroxyl groups in C-ring of phenanthridone alkaloids are crucial to biological effects.