Design, synthesis, and docking studies of quinazoline analogues bearing aryl semicarbazone scaffolds as potent EGFR inhibitors

Two series of quinazoline derivatives bearing aryl semicarbazone scaffolds (9a–o and 10a–o) were designed, synthesized and evaluated for the IC50 values against four cancer cell lines (A549, HepG2, MCF-7 and PC-3). The selected compound 9o was further evaluated for the inhibitory activity against EGFR kinases. Four of the compounds showed excellent cytotoxicity activity and selectivity with the IC50 values in single-digit μM to nanomole range. Two of them are equal to more active than positive control afatinib against one or more cell lines. The most promising compound 9o showed the best activity against A549, HepG2, MCF-7 and PC-3 cancer cell lines and EGFR kinase, with the IC50 values of 1.32 ± 0.38 μM, 0.07 ± 0.01 μM, 0.91 ± 0.29 μM and 4.89 ± 0.69 μM, which were equal to more active than afatinib (1.40 ± 0.83 μM, 1.33 ± 1.28 μM, 2.63 ± 1.06 μM and 3.96 ± 0.59 μM), respectively. Activity of the most promising compound 9o (IC50 56 nM) against EGFR kinase was slightly lower to the positive compound afatinib (IC50 1.6 nM) but more active than reference staurosporine (IC50 238 nM). The result of flow cytometry, with the dose of compound 9o increasing, which indicated the compound 9o could induce remarkable apoptosis of A549 and cells in a dose dependent manner. Structure–activity relationships (SARs) and docking studies indicated that replacement of the cinnamamide group by aryl semicarbazone scaffolds slightly decreased the anti-tumor activity. The results suggested that hydroxy substitution at C-4 had a significant impact on the activity and replacement of the tetrahydrofuran group by methyl moiety was not beneficial for the activity.