Copper-catalyzed three-component reaction: solvent-controlled regioselective synthesis of 4-amino- and 6-amino-2-iminopyridines.

Regioselective synthesis of multisubstituted 4-amino- and 6-amino-2-iminopyridines has been developed via the copper-catalyzed three-component reaction based on the reaction conditions selection. The reaction of sulfonyl azides, alkynes, and 2-[(amino)methylene]malononitriles catalyzed by copper(I) iodide in tetrahydrofuran at room temperature afforded substituted 4-amino-2-iminopyridines, whereas, in N,N-dimethylformamide at 50 °C under N2, it generated substituted 6-amino-2-iminopyridines as predominant products.