Noteworthy effect of slight variation in aliphatic chain length of trisubstituted imidazole inhibitors against epidermal growth factor receptor L858R/T790M/C797S mutant in cancer therapy

11h is a very potent inhibitor against epidermal growth factor receptor triple mutation L858R/T790M/C797S (EGFR) with 13-fold stronger potency than the FDA-approved osimertinib. Recently, two new EGFR inhibitors, 11d and 11e, were reported which revealed 2.8- and 2.3-fold stronger potency than 11h, respectively. 11h, 11d, and 11e have the same structures but differ only in their aliphatic chain length. However, the exact effects of differential aliphatic chain length on the inhibitory potencies of these compounds require further elaboration at the atomistic level, hence the objective of this report. Various computational tools were employed for this purpose. From our findings, it was revealed that van der Waals (vdW) interactions modulate the binding mechanisms of these inhibitors and play the most important role in the differential inhibitory activities of 11d, 11h, and 11e. The strong hydrogen bond formation between the aliphatic chain of 11d and key residue ARG841 was recognized as the reason for its higher activity and inhibitory potency relative to 11h and 11e. Moreover, the extension of the N-terminal loop into the active site for vdW interaction with the phenyl group of 11e and carbon-hydrogen bond formed between the aliphatic chain of 11e and LEU718 engendered a higher activity of 11e than 11h.