Open-air N-arylation of N-H heterocycles with arylboronic acids catalyzed by copper(II) Schiff base complexes

Two copper Schiff base complexes, in both homogeneous and heterogeneous forms, were prepared and characterized by using elemental analysis, FTIR, UV-Vis spectroscopy and scanning electron microscopy. The catalytic performances of these complexes were studied in the N-arylation of N-H heterocycles with arylboronic acids in methanol without any added base at 40 A degrees C under open air. The effects of various parameters such as solvent and temperature on the reaction system were studied. The reaction is applicable to a wide variety of N-H heterocycles and arylboronic acids. The heterogeneous catalyst was recovered by simple filtration, and reusability experiments showed that this catalyst can be used five times without much loss in the catalytic activity.