Synthesis of 1,4-and 1,5-Diaryl-1H-Imidazoles

A simple method for the synthesis of 1,4- and 1,5-diarylimidazoles has been developed. The method is based on the condensation of appropriate alpha-diketone monooxime with aromatic amines and formaldehyde in the presence of boron trifluoride etherate leading to the formation of stable boron trifluoride complexes of imidazole N-oxides. Further reduction of these complexes led to the formation of corresponding imidazoles.