Synthesis of novel pyridopyrimidine‐thiazolidione‐1,2,4‐oxadiazoles as potent EGFR targeting anticancer agents

In this study, we designed and synthesized a number of novel pyrido[3,4‐d]pyrimidine‐thiazolidine‐1,2,4‐oxadiazole derivatives and investigated them in vitro for their inhibitory action toward epidermal growth factor receptor (EGFR) kinases and antiproliferative activity against two different cell lines, MCF‐7 and A‐549. When compared to the lead chemicals, 5‐fluorouracil and erlotinib, some of the compounds demonstrated acceptable activity. Among them, the most promising compounds 4d and 4e displayed potent anticancer activity against both MCF‐7 and A‐549 cell lines (IC50 values remaining: 1.97 ± 0.28 μM to 8.14 ± 0.52 μM, respectively); the comparative IC50 values for 5‐fluorouracil and erlotinib in these cell lines were 5.56 ± 0.34 μM, 12.66 ± 0.76 μM, and 3.64 ± 0.49 μM, 9.54 ± 0.75 μM, respectively; as well as excellent kinase inhibitory activities (EGFR: IC50 = 0.34 ± 0.07 μM and 0.42 ± 0.06 μM) were more effective than the conventional drug Erlotinib (IC50 = 0.42 ± 0.02 μM).