Synthesis and biological evaluation of novel 2-aralkyl-5-substituted-6-(4′-fluorophenyl)-imidazo[2,1-b][1,3,4]thiadiazole derivatives as potent anticancer agents

► Levamisole, derivatives has been reported as potential antitumor agent in patients with small tumor burdens. We synthesized and evaluated biological activity of novel analogues of levamisole on leukemia cells. ► The cytotoxicity was studied using trypan blue and MTT assays and found that 3a, 4a, and 4c exhibited strong cytotoxicity. ► Among these we chose 4a (IC50, 8 μM) for understanding the mechanism of cytotoxicity. ► FACS analysis in conjunction with mitochondrial membrane potential and DNA fragmentation studies suggested that 4a induced apoptosis, but not cell cycle arrest.