Uncatalyzed condensation between aryl-1, 2-diamines and diethyl bromomalonate: a one-pot access to substituted ethyl 3-hydroxyquinoxaline-2-carboxylates
2,3-Disubstituted quinoxalines are usually synthesized by condensation of aryl-1,2-diamines with epoxides 12 or α-dicarbonyl compounds or their equivalents. 13 Difunctional quinoxalines can also be prepared by cyclization of α-aryliminooximes of α-dicarbonyl compounds 14 and by POCl 3 mediated hetero-annulation of α-nitroketene N,S-anilinoacetals. 15 Very recently, while this manuscript was being prepared, a report appeared describing an efficient ...