An efficient synthesis of quinoxalines catalyzed by monoammonium salt of 12-tungstophosphoric acid

Monoammonium salt of 12-tungstophosphoric acid [(NH4)H2PW12O40] catalyst was used for the synthesis of biologically important quinoxaline derivatives in excellent yields from various aromatic 1,2-dicarbonyl and 1,2-diamines. The methodology has the advantages of mild reaction conditions with simple workup procedure, even for the synthesis of quinoxaline derivatives from sterically hindered diamine.