Functionalized pyrazine-2-carboxamides in the synthesis of new palladium-based potential cytotoxic agents

The reactions of α-(aminoalkyl)diphenylphosphine sulfides with pyrazine-2-carbonyl chloride hydrochloride afforded two novel representatives of non-classical amide-based pincer ligands. The latter were shown to furnish Pd^II complexes with either bi- or tridentate coordination modes of the ligands, depending on the reaction conditions. The cytotoxicity assays revealed remarkable activity of one of the resulting cyclopalladated derivatives, especially, towards hematopoietic cancer cell lines.