Tandem one-pot palladium-catalyzed coupling of hydrazones, haloindoles, and amines: synthesis of amino-N-vinylindoles and their effect on human colon carcinoma cells.

The synthesis of amino-substituted N-vinylazoles was achieved by a new palladium-assisted tandem catalytic reaction involving N-tosylhydrazones, halo-substituted azoles, and amines. Accordingly, two Csp(2)-N bonds were formed through two mechanistically distinct reactions using a single Pd(II)/Pd(0) catalyst system in a one-pot fashion. This work paves the way for the design of biological relevant compounds in an amino-substituted N-vinylindole series. Among several polyoxygenated derivatives evaluated, compounds 5e and 5u were found to exhibit good antiproliferative activity.