1-Butyl-3-methylimidazolium tribromide ([bmim]Br 3 ), is an efficient and novel reagent for the regioselective monobromination of arylamines. We found that the reaction of aniline (1a) with [bmim]Br 3 (Scheme [1] ), occurred rapidly under solvent-free conditions at -10 °C and was complete within two minutes. The reaction leads to selective monobromination, preferentially in the para position (Table [1] , entry 1), to produce p-bromoaniline (2a). In similar fashion, the ...
