One-Pot Synthesis of Fused Isoxazolo[4′,5′:3,4]pyrrolo[2,1-b] Quinazolines as Potent EGFR Targeting Anticancer Agents

In response to the need for scaffolds for medical applications, synthetic chemists have developed simple and efficient methods for optimal synthesis. To investigate the synthesis of fused isoxazoles in the presence of [3+2] cycloaddition followed by C-N bond formation reaction between 3-((4-iodo-3-phenylisoxazol-5-yl)methyl)quinazolin-4(3H)-one and various nitrile oxides was carried out by previously reported conditions. The cancer activities of the synthesized compounds were then tested in vitro against two cancer cell lines, MCF-7 and A-549. Three of the compounds, 3-(3,5-dichlorophenyl) isoxazolo[4 ',5 ':3,4]pyrrolo[2,1-b]quinazolin-9(11H)-one, 3-(4-fluorophenyl)isoxazolo[4 ',5 ':3,4]pyrrolo[2,1-b]quinazolin-9(11H)-one, and 3-(4-(trifluoromethyl)phenyl)isoxazolo[4 ',5 ':3,4] pyrrolo[2,1-b] quinazolin-9(11H)-one has shown superior activity against the non-small-cell lung cancer cell line (A-549) than the standards 5-fluorouracil and erlotinib. Later, in vitro EGFR results revealed that a more potent compound was more effective than the conventional medicine, erlotinib. In silico investigations of more potent compounds and erlotinib on the EGFR protein indicated that more potent compounds had comparable binding energies and inhibition constants to erlotinib.