Synthesis and Cytotoxic Evaluation of Quinazolin-4(3H)-one Derivatives Bearing Thiocarbamate, Thiourea or N-Methyldithiocarbamate Side Chains

We have previously found that the dithiocarbamate derivatives of quinazolin-4(3H)-one could act as cytotoxic agents against a panel of human tumor cell lines. To investigate the contribution of dithiocarbamate moiety to the cytotoxic activity, three series of novel quinazolin-4(3H)-one derivatives bearing thiocarbamate, thiourea or N-methyldithiocarbamate side chains were synthesized and tested for their cytotoxic activity against human cancer cell lines A549, MCF-7, HeLa, HT29 and HCT-116 by MTT assay. The results showed that transformation of the dithiocarbamate moiety in lead compound I to thiocarbamate or thiourea led to a decrease or loss of cytotoxic activity. Some N-alkylated analogs of lead compound II preferentially inhibited the proliferation of A549 cells, although their potencies were not improved in comparison with the unalkylated counterparts. The structure-activity relationship obtained in this research will be beneficial for further synthesis and discovery of effective cytotoxic agents.