The oxidative cleavage of an anti-Hugerschoff product: a mild environmentally benign one pot synthesis of ureas from isothiocyanates

Abstract

In a simple, one-pot procedure, H₂O₂ has been utilised for the synthesis of unsymmetrical ureas from thioureas obtained by the reaction of aryl isothiocyanates with aliphatic secondary amines. The reaction proceeds via the formation of a thioamido guanidino moiety (the anti-Hugerschoff product) which then undergoes further oxidative desulfurization in the presence of excess H₂O₂ to afford the desired product. The scope of this phosgene free urea synthesis has been extended to various substrates.