Synthesis and antitumor activities of novel hybrid molecules containing 1,3,4-oxadiazole and 1,3,4-thiadiazole bearing Schiff base moiety

A series of novel hybrid molecules containing 1,3,4-oxadiazole and 1,3,4-thiadiazole bearing Schiff base moiety were designed, synthesized and evaluated for their in vitro antitumor activities against SMMC-7721, MCF-7 and A549 human tumor cell lines by CCK-8 assay. The bioassay results demonstrated that most of the tested compounds showed potent antitumor activities, and some compounds exhibited stronger effects than positive control 5-fluorouracil (5-FU) against various cell lines. Among these compounds, compound 8d showed the best inhibitory effect against SMMC-7721 cells, with IC50 value of 2.84 mu M. Compounds 8k and 8n displayed highly effective antitumor activities against MCF-7 cells, with IC50 values of 4.56 and 4.25 mu M, respectively. Compounds 8a and 8n exhibited significant antiproliferative activity against A549 cells, with IC50 values of 4.11 and 4.13 mu M, respectively. The pharmacological results suggest that the substituents of phenyl ring on the 1,3,4-oxadiazole are vital for modulating antiproliferative activities against various tumor cell lines. (C) 2014 Elsevier Ltd. All rights reserved.