Synthesis, Labeling and Biological Evolution of New Thiopyrano [2, 3-b] pyridine Derivatives as Potential Anticancer Agents

The new thiopyrano[2,3-b]pyridines 4–9 could be synthesized from the nicotinonitrile derivative 1. The cytotoxicity activity of the selected compounds 5, 6 and 8 was tested against MCF-7 and HCT-116 cell lines. The compound 5 (TP₅) exhibited significant inhibitory activity and displayed the most potent activity, more than 6 and 8. The compound 5 with potent inhibitory activity in tumor growth inhibition would be a potential anticancer agent. In the light of this result, the labeled ¹²⁵I-compound 5 (¹²⁵I-TP₅) was prepared and its cytotoxicity against ascites tumor in mice has been evaluated. The results show that compound 5 (TP₅) may be potentially used as a radiopharmaceutical for tumor diagnosis when labeled with ¹²⁵I.