Synthesis and Cytotoxicity of N-Substituted Dibenzo[a,j]xanthene-3,11-dicarboxamide Derivatives

In order to study the structure-activity relationships of xanthene derivatives, four series of N-substituted 14-aryl-14H-dibenzo[a,j]xanthene-3,11-dicarboxamide derivatives were synthesized. The structures of all compounds were identified by (1)H-NMR, HR-MS and IR spectra, in which compounds 6a–h were further identified by (13)C-NMR spectra. The in vitro antitumor activity of the synthesized compounds was tested by MTT assay. Most of them displayed strong inhibitory activity on human hepatocellular carcinoma cell lines (SK-HEP-1, HepG2 and SMMC-7721 cells) and acute promyelocytic leukemia NB4 cells. Compounds 6c–6e exhibited significant inhibitory activity against NB4 cells with IC(50) values of 0.52 μM and 0.76 μM, respectively, much lower than 5.31 μM of the positive control As(2)O(3).