Cyclization of 1,1,2,2-tetracyanoethane by the semicarbazones and oximes of carbonyl compounds
Abstract1,1,2,2-Tetracyanoethane undergoes cyclization with semicarbazones and oximes with the formation of 5-substituted 2-amino-3,4,4-tricyano-N-ureido(N-hydroxy)-2-pyrrolines. When heated, the latter readily eliminate HCN, forming the corresponding 3,4-dicyano-N-ureidopyrroles. The reaction of the N-ureidopyrroles with benzaldehyde leads to 1,2-di(benzylidenamino)-3,4-dicyanopyrroles.