Preparation of N,N-Dimethyl-N′-Arylureas Using S,S-Dimethyl Dithio­carbonate as a Carbonylating Reagent

Abstract

A new, general method for the preparation of N,N-di­methyl-N′-arylureas using S,S-dimethyl dithiocarbonate as a phosgene substitute is reported. The method has been set up according to four procedures, all including three steps: (1) reaction of S,S-di­methyl dithiocarbonate with dimethylamine to give S-methyl N,N-dimethylthiocarbamate; (2) halogenation with various halogenating reagents (chlorine, methanesulfenyl chloride, bromine, and methanesulfenyl bromide) to give N,N-dimethylcarbamoyl chloride or bromide; (3) in situ reaction with primary arylamines. All the target products were obtained in high yields (85-98%; 16 reactions, average yield 93%) and with high purity. Also noteworthy is the recovery of byproducts of industrial interest, namely methanethiol and dimethyl disulfide, with complete exploitation of the reagent S,S-dimethyl dithiocarbonate.