Synthesis, Anticancer and EGFR Inhibitory Activity of Novel Benzo[b][1,4]oxazine-1,3,4-oxadiazolo-1,2,3-triazoles

Abstract— Objective: This study involves the design, synthesis, characterization, and both in vitro and in silico evaluation of novel benzo[b][1,4]oxazine-1,3,4-oxadiazolo-1,2,3-triazoles (VIIIa–VIIIo) and their inhibitory action against EGFR. Methods: All synthesized compounds were evaluated for their anticancer activity against selected cancer cell lines in vitro using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the EGFR enzymatic assay. More potent compounds were further screened for their in silico molecular docking. Results and Discussion: ESI-MS, ¹H, and ¹³C NMR spectroscopy confirmed the identity of all prepared derivatives. Compound (VIIIi) exhibited more potent activity against MCF-7 cancer cells with an IC₅₀ value of 4.22 ± 0.31 μM. Additionally, compound (VIIIk) demonstrated equipotent activity against both MCF-7 and A-549 cell lines, with IC₅₀ values of 4.89 ± 0.26 and 5.48 ± 0.32 μM, respectively. These results were compared to the standard erlotinib. Further evaluation of the EGFR inhibitory activity of the more potent compounds revealed that compounds (VIIIi) and (VIIIk) exhibited significant activity. All potent compounds showed higher binding energies compared to the standard erlotinib. Conclusions: A series of benzo[b][1,4]oxazine-1,3,4-oxadiazolo-1,2,3-triazoles were synthesized and investigated for in vitro anticancer activity. Some compounds showed excellent efficacy against MCF-7 and A-549 cell lines. The more potent compounds were less harmful to the normal HEK293 cell line. Compounds (VIIIi) and (VIIIk) demonstrated potent EGFR inhibitory activity compared to the standard. Finally, slight modifications to the potent compound (VIIIi) could make it a promising future therapeutic candidate for cancer treatment. All potent compounds exhibited significant binding energies, ranging from ­–9.77 to –10.97 kcal/mol, compared to the standard erlotinib (­–7.69 kcal/mol).