Design, synthesis and antiproliferative evaluation of fluorenone analogs with DNA topoisomerase I inhibitory properties.

A series of 2,7-diamidofluorenones were designed, synthesized, and screened by SRB assay. Some synthesized compounds exhibited antitumor activities in submicromolar range. Ten compounds (3a, 3b, 3c, 3g, 3j, 3l, 4a, 4h, 4i, and 4j) were also selected by NCI screening system and 3c (GI50=1.66 μM) appeared to be the most active agent of this series. Furthermore, 3c attenuated topoisomerase I-mediated DNA relaxation at low micromolar concentrations. These results indicated that fluorenones have potential to be further developed into anticancer drugs.