Synthesis and Biological Evaluation of Novel 2,4'-bis Substituted Diphenylamines As Anticancer Agents and Potential Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Four new series of 2,4'-bis diphenylamine hydrazones 14, 2,4'-bis aminothiadiazole 16, 2,4'-bis mercaptotriazole 17-18 and 2,4'-bis mercapto-oxadiazole diphenylamine derivatives 19-20 were synthesized and evaluated for their ability to inhibit EGFR tyrosine kinase. Compound N-ethyl-5-{2-[4-(5-(ethylamino)-1,3,4-thiadiazol-2-yl)- phenylamino]phenyl}-1,3,4-thiadiazol-2-amine 16a was the most active enzyme inhibitor (98% inhibition at 10 microM). Moreover, all compounds that showed enzyme inhibition activity were tested in vitro on human breast carcinoma cell line (MCF-7) in which EGFR is highly expressed. The tested compounds exploited potent antitumor activity with IC(50) values ranging 0.73-2.38 microM. Molecular modeling and docking of the synthesized compounds into the active site of EGFR kinase domain showed good agreement with the obtained biological results. The present work represents a novel class of diphenylamine based derivatives with potent cytotoxicity and promising EGFR PTK inhibition activity.