Discovery of 7-bromo-1,4-dihydrothieno[3’,2’:5,6]thiopyrano[4,3-c]pyrazole-3-carboxamide derivatives as the potential epidermal growth factor receptors for tyrosine kinase inhibitors

Small molecule tyrosine kinase inhibitors (TKIs) targeting at epidermal growth factor receptor (EGFR) in recent years have made great progress in the treatment of advanced non-small cell cancer (NSCLC). Although as the first-line treatment for sensitizing EGFR mutation-positive metastatic NSCLC, gefitinib has also behaved quite a lot of side effect and EGFR tolerance. Herein, a novel series of 7-bromo-1,4-dihydrothieno[3’,2’:5,6]thiopyrano[4,3-c]pyrazole-3-carboxamide derivatives were designed and synthesized, and screened for their inhibitory activity on the EGFR high-expressing human lung adenocarcinoma cell line A549 and human large cell lung cancer cell line NCI-H460 by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay. The calculated IC50 values were reported. Compound 8h demonstrated the most potent inhibitory activity (IC50 = 9.57 ± 2.20 μmol L–1 for A549 and IC50 = 13.04 ± 1.21 μmol L–1 for NCI-H460), comparable to the positive-control gefitinib (IC50 = 8.58 ± 1.65 μmol L–1 for A549 and IC50 = 18.66 ± 5.01 μmol L–1 for NCI-H460). Conclusively, 7-bromo- 1,4-dihydrothieno[3’,2’:5,6]thiopyrano[4,3-c]pyrazole-3-carboxamide derivatives as the EGFR–TKIs were discovered, and could be used as potential leading compounds for further research.