Synthesis and antitumor evaluation of some new derivatives and fused heterocyclic compounds derived from thieno[2,3-b]pyridine

On the basis of the proven activity of thieno[2,3-b]pyridines as anticancer, we have designed to synthesize a novel several heterocyclic compounds utilizing thieno[2,3-b]pyridine as a skeleton through various chemical reactions. The synthesized compounds bear rings that are either directly attached to the thieno[2,3-b]pyridine as in compounds 4 to 6 and 9 or connected through an amide bridge as compounds 2, 3a-b, 7, and 8. As well as, compounds 10, 12 to 28, 30, 31, and 33 to 36 bear fused rings to the thieno[2,3-b]pyridine backbone. The newly synthesized compounds were screened for their antiproliferative activity in vitro against hepatocellular carcinoma (HepG-2) and breast cancer (MCF-7) compared with the standard drug (doxorubicin). Compounds 3b, 4, 6, 22, and 28 exhibited promising growth inhibitory effect toward both HepG-2 and MCF-7 cell lines with IC50 values ranging from 5.88 to 11.70 mu g/mL and 9.64 to 15.10 mu g/mL, respectively.