A Sandmeyer type reaction for bromination of 2-mercapto-1-methyl-imidazoline (N2C4H6S) into 2-bromo-1-methyl-imidazole (N2C4H5Br) in presence of copper(I) bromide

2-Mercapto-1-methyl-imidazoline (N2C4H6S) is converted at room temperature into 2-bromo-1-methyl-imidazole (N2C4H5Br) in presence of copper(I) bromide in acetonitrile-chloroform mixture via extrusion of sulfur as sulfate and oxidation of Cu-I into Cu-II. 2-Bromo-1-methyl-imidazole was isolated as its self assembled tetranuclear Cu-II cluster, [Cu-4(eta(1)-N-(N2C4H5Br)(4)(mu(4)-O)(mu-Br)(6)] 1 {eta(1)-N-(N2C4H5Br) = 2-bromo-1-methyl-imidazole}.