General microwave-assisted protocols for the expedient synthesis of quinoxalines and heterocyclic pyrazines

Functionalized quinoxalines and heterocyclic pyrazines are expediently prepared in excellent yields (69-99%) from common 1,2-diketone intermediates under microwave irradiation. In addition to being general for a variety of aryl/heteroaryl 1,2-diamines and 1,2-diketones, this protocol suppresses the formation of polymeric species, characteristic of traditional thermal conditions. (C) 2004 Published by Elsevier Ltd.