Simple synthesized Mannich bases as ligands in Cu-catalyzed N-arylation of imidazoles in water

1,4-Bis(2-hydroxy-5-methoxybenzyl)piperazine and its analogues were used as efficient ligands for CuI-catalyzed N-arylation of imidazoles with aryl halides in water under mild conditions (120 A degrees C for 12 h) with 10 mol% of CuI, 20 mol% of the Mannich base, and two equivalents of KOH or K(2)CO(3) in the presence of 10 mol% phase transfer catalyst (n-Bu)(4)NBr. A variety of products were synthesized in moderate to excellent yields using this inexpensive catalytic system.