Design, synthesis and biological evaluation of 6-(nitroimidazole-1H-alkyloxyl)-4-anilinoquinazolines as efficient EGFR inhibitors exerting cytotoxic effects both under normoxia and hypoxia

• 18 novel EGFR inhibitors were designed and synthesized.
• 5 compounds were more potent than gefitinib under normoxia and hypoxia.
• 15c could be reductive activated to generate reactive radicals under hypoxia.
• 15c was relatively stable under normoxia and easily activated under hypoxia.

A series of novel 6-(nitroimidazole-1H-alkyloxyl)-4-anilinoquinazoline derivatives (15a–15r) were designed, synthesized and evaluated as efficient EGFR inhibitors through introduction of hypoxia activated nitroimidazole moiety into the quinazoline scaffold of EGFR inhibitors. The majority of these newly synthesized compounds exhibited comparable EGFR inhibitory activities to gefitinib and moderate to excellent anti-proliferative activities against HT-29 cells under normoxia and hypoxia. The most promising compound 15c displayed the IC50 value of 0.47 nM against EGFR kinase and excellent cytotoxic effect against HT-29 cells under normoxia and hypoxia with the IC50 values of 2.21 μM and 1.62 μM, respectively. The mimic reductive activation study revealed that compound 15c exerted reductive activation properties under hypoxia, which were consistent with the in vitro metabolic study, wherein 15c was easily reductive activated under hypoxia and much more stable under normoxia. All these results suggested that 15c was a potential cancer therapeutic agent both under normoxia and hypoxia and was worth of further development.

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