Synthesis and anticancer activity studies on some 2-chloro-1,4-bis-(5- substituted-1,3,4-oxadiazol-2-ylmethyleneoxy) phenylene derivatives

2-Chloro-1,4-phenylenedioxy-bis-acetyl hydrazine 1 on reacting with aromatic carboxylic acids in the presence of phosphorus oxychloride affords 2-chloro-bis-1,3,4-oxadiazoles 3a-f and 4a-d. Aroyl hydrazine 1 on reacting with carbon disulphide under basic condition gives oxadiazole-2-thione 2. Three out of four tested compounds show anticancer activity in the primary anticancer assay. These compounds have been extensively screened against a panel of sixty cancer cell lines derived from leukemia, lung, colon, CNS, melanoma, ovarian, renal, prostate and breast cancer, respectively. It is interesting to note that compounds 3d and 3f show significant anticancer activity against most of the cell lines with GI50 values <100 μM concentrations.