Design, synthesis and anticancer evaluation of substituted aryl-1,3-oxazole incorporated pyrazole-thiazole derivatives

A new library of different types of aryl ring attached pyrazole-thiazole-oxazoles (11a-j) was prepared and their structures were characterized by ¹HNMR, ¹³CNMR and mass spectral data. Further, these compounds were evaluated for anticancer effects towards a panel of four human cancer cell lines including SiHa (cervix cancer), A549 (lung cancer), MCF-7 (breast cancer) and Colo-205 (colon cancer) by the MTT method, with etoposide used as a reference drug. Most of the tested compounds exhibited good anticancer activity with IC₅₀ values ranging from 0.13±0.046 µM to 18.6 ± 6.34 µM and the reference drug showed values ranging from 0.14 ± 0.017 µM to 3.11±0.11 µM, respectively. Among these compounds 11e, 11f, 11 g and 11 h displayed more potent anticancer activity as etoposide. All compounds showed selective cytotoxicity against cancer cells but not against normal Vero cells (IC₅₀ = >24 µM), justifying the designing approach to develop a selective anticancer agent.