An efficient methodological approach for synthesis of selenopyridines: generation, reactions, anticancer activity, EGFR inhibitory activity and molecular docking studies

In the present work, we successfully synthesized Se -alkyl selenopyridines 1 and 3 , selenopheno[2,3- b ]pyridine 2 , and bis-selenopyridine 4 derivatives using an eco-friendly method by utilizing NaHSe instead of toxic hydrogen selenide. The effect of the temperature on the reaction was screening at various temperatures. The regiospecific reaction of selenopyridine 1 with bromine afforded an unexpected product 4,6-diamino-5-bromo-2-[(cyanomethyl)selenyl]-pyridine-3-carbonitrile ( 5 ), which was cyclized to selenopheno[2,3- b ]pyridine ( 7 ) by refluxing in the presence of TEA. While its treatment with thiophenol and/or p -chlorothiophenol gave 8a , b . On the other hand, its reaction with aminothiophenol afforded 2-(benzo[ d ]-thiazol-2-yl)-5-bromoselenopheno[2,3- b ]pyridine-3,4,6-triamine ( 9 ). Also, N -(2-cyano-4-methyl-5 H -1-seleno-3,5,8-triazaacenaphthylen-7-yl)acetamide ( 11 ) and a novel series of selenoazo dyes 12a – d were synthesized by treatment of selenopheno[2,3- b ]pyridine 2 with acetic anhydride and/or diazonium chlorides of aromatic amines, respectively. Then, we ascertained the potential activity of synthesized compounds against highly metastatic prostate cancer cells (PC-3) and osteosarcoma cells (MG-63) and found that 12a , 12b , 12c , and 12d were more cytotoxic than doxorubicin in both tested cell lines, showing nearly the same anticancer activity with IC 50 values ranging from 2.59 ± 0.02 µM to 3.93 ± 0.23 µM. Mechanistically, the most potent compounds 12a and 12b proved to be potent EGFR inhibitors with IC 50 values of 0.301 and 0.123 µM, respectively, compared to lapatinib as a positive reference (IC 50 = 0.049 µM). Moreover, the docking results are in good agreement with the anticancer activity as well as the EGFR inhibitory activity, suggesting these two compounds as promising EGFR anticancer candidates. Graphical abstract