Synthesis of new unsymmetric N,N′-dipyridylurea derivatives by selenium and selenium dioxide-catalyzed reductive carbonylation of substituted nitropyridines

Without using phosgene, a series of new unsymmetric N,N′-dipyridylurea derivatives have been synthesized in moderate to good yields by the one-pot reductive carbonylation of substituted nitropyridines. These reactions utilize selenium or selenium dioxide as the catalyst, aminopyridine derivatives as co-reagents, and carbon monoxide as the carbonyl source.