Iodine catalyzed synthesis of imidazo[1,2-a]pyrazine and imidazo[1,2-a]pyridine derivatives and their anticancer activity

An efficient iodine-catalyzed method for synthesizing imidazo[1,2-a]pyrazines and imidazo[1,2-a]pyridines via one-pot three-component condensations has been reported. The product, generated in situ by the reaction between an aryl aldehyde and 2-aminopyridine or 2-aminopyrazine, undergoes [4 + 1] cycloaddition with tert-butyl isocyanide, affording the corresponding imidazopyrazine and imidazopyridine derivatives in good yields. The photophysical properties of these new fluorescent derivatives are also presented. The anti-cancer activities of the synthesized compounds (10a-m) and (12a-l) were evaluated against four cancer cells (Hep-2, HepG2, MCF-7, A375) and the normal Vero cell. Significant anti-cancer activities were observed and compared with the standard drug Doxorubicin. In vitro experimental results revealed that compound 12b is a promising lead with IC50 values of 11 mu M, 13 mu M, 11 mu M, 11 mu M, and 91 mu M against Hep-2, HepG2, MCF-7, A375, and Vero, respectively.