A simple and efficient method for the synthesis of highly substituted imidazoles using 3-aroylquinoxalin-2(1H)-ones

Abstract 3-Aroylquinoxalin-2(1 H )-ones were found to be hetero analogues of α-diketones for the efficient, one-pot, three component synthesis of 2,4,5-trisubstituted imidazoles and imidazo[1,5- a ]quinoxalin-4(5 H )-ones in boiling methanol. The key advantages of this process are high yields, ready availability and low cost of 3-aroylquinoxalin-2(1 H )-ones and easy work-up and separation of the products by non-chromatographic methods. Furthermore, the presence of an ortho -iminoanilide fragment at position 4 of the imidazoles obtained has made it possible to produce 2-(imidazol-4-yl)benzimidazoles in almost quantitative yields.