Optimal method were developed for the green synthesis of quinoxaline derivatives based on the highly efficient and simple condensation reaction of various aromatic 1,2-diketones and 1,2-diamines in nearly quantitative yields in water. In this method we did not use any catalyst. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route for synthesis of quinoxalines.

Efficient synthesis of quinoxaline derivatives from the reaction of ?-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA) such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced.

2,4,5-Trisubstituted imidazoles have many pharmaceutical properties and can be prepared via reaction of 1, 2-diketones with aldehydes in the presence of an acidic catalyst. In this work, we have prepared 2,4,5-trisubstituted imidazoles in the presence of trichloromelamine as a source of positive chlorine. Short reaction times, high yield, simplicity of operation and easy work-up are some advantages of this method.