Catalysis by ionic liquids: Significant rate acceleration with the use of [pmIm]Br in the three-component synthesis of dithiocarbamates

An easily accessible neutral ionic liquid, 1-methyl-3-pentylimidazolium bromide, promoted a one-pot three-component condensation of an amine, carbon disulfide, and an activated alkene/dichloromethane/epoxide to produce the corresponding dithiocarbamates in high yields at room temperature. The reactions are very fast in ionic liquids relative to those in other reaction media. These reactions do not require any additional catalyst or solvent. The ionic liquid can be recovered and recycled for subsequent reactions. A plausible mechanism is suggested. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).