Discovery of 4,5-Dihydro-1H-thieno[2',3':2,3]thiepino [4,5-c]pyrazole-3-carboxamide Derivatives as the Potential Epidermal Growth Factor Receptors for Tyrosine Kinase Inhibitors.

The epidermal growth factor receptors (EGFRs), in which overexpression (known as upregulation) or overactivity have been associated with a number of cancers, has become an attractive molecular target for the treatment of selective cancers. We report here the design and synthesis of a novel series of 4,5-dihydro-1H-thieno [2',3':2,3]thiepino[4,5-c]pyrazole-3-carboxamide derivatives and the screening for their inhibitory activity on the EGFR high-expressing human A549 cell line using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). A Docking simulation was performed to fit compound 6g and gifitinib into the EGFR to determine the probable binding models, and the binding sites and modes conformation of 6g and gifitinib were exactly similar, the two compounds were stabilized by hydrogen bond interactions with MET769. Combining with the biological activity evaluation, compound 6g demonstrated the most potent inhibitory activity (IC50 = 9.68 ± 1.95 μmol·L⁻1 for A549). Conclusively, 4,5-dihydro-1H-thieno[2',3':2,3]thiepino[4,5-c]pyrazole-3-carboxamide derivatives as the EGFR tyrosine kinase inhibitors were discovered, and could be used as potential lead compounds against cancer cells.