Rational design, synthesis and anticancer screening of 1,2,4-oxadiazole incorporated thieno[2,3-d]thiazole-isoxazole-pyridine derivatives

We have design and synthesized a new series of 1,2,4-oxadiazole incorporated thieno[2,3-d]thiazole-isoxazole-pyridine analogues (13a-j) and were confirmed by ¹H NMR, ¹³C NMR and mass spectral data. Further, the newly synthesized compounds (13a–j) were evaluated for their preliminary anticancer activity against a panel of four human cancer cell lines such as MCF-7 (breast cancer), A549 (lung cancer), Colo-205 (colon cancer) & A2780 (ovarian cancer) by using of MTT method, the known chemotherapeutic agent as etoposide used as positive control. Most of the tested compounds were displayed good to moderate activities on all cell lines. The IC₅₀ values showed compound ranges from 0.01 ± 0.009 µM to 8.41 ± 5.48 µM. Where positive control showed values range from 3.34 ± 0.152 µM to 0.17 ± 0.034 µM. Among them, compound 13a, 13b, 13c, 13d, 13e and 13f were showed more potent activity than etoposide. Predominantly, the compound 13a showed potent anticancer activity against MCF-7, A549, Colo-205, and A2780 cancer cell lines with IC₅₀ values of 0.02 ± 0.007 µM, 0.01 ± 0.009 µM, 0.13 ± 0.052 µM, and 0.11 ± 0.083 µM.