One-Step Synthesis of Dicarboxamides through Pd-Catalysed Aminocarbonylation with Diamines as N-Nucleophiles

An efficient one-step synthetic strategy was used to prepare a set of dicarboxamides through palladium-catalysed aminocarbonylation of iodoalkenyl and iodoaryl compounds, with use of various alkyl- and aryldiamines as N-nucleophiles. The isolated yields of the dicarboxamides depended significantly on the iodo substrate and diamine structures, as well as on the reaction conditions, the best one (ca. 70%) being achieved with 1-iodocyclohexene as substrate and 1,4-diaminobutane as nucleophile, at 100 degrees C and 30 bar of CO. When iodobenzene was used as model aryl halide, the highest yield of the target dibenzamides (ca. 65%) was obtained with 1,4-diaminobenzene as coupling amine, at 100 degrees C and 10 bar of CO. Preliminary studies on their in vitro cytotoxicity against human lung carcinoma A549 cells showed N,N-(butane-1,4-diyl)dibenzamide and androst-16-ene-based dicarboxamides to be the most efficient cytotoxic agents, with IC50 values of approximately 40 M.