A green synthesis of quinoxalines and 2,3-dihydropyrazines

Quinoxaline and dihydropyrazine derivatives were obtained in high yields by simple addition 1,2-diamines and 1,2-dicarbonyl compounds in water. In some cases, the products spontaneously precipitates from the reaction mixture, making it possible to recover and reuse the mother liquor for further condensations. 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 to quinoxalines and dihydropyrazines