CeCl3·7H2O-Catalyzed Synthesis of Quinoxaline Derivatives in Liquid PEG-400

A mild and efficient route for the synthesis of quinoxaline derivatives utilizing cerium chloride heptahydrate (CeCl 3 •7H 2 O) as a novel catalyst in poly(ethylene glycol) (PEG-400) under mild conditions was described.Nitrogen-containing heteroaromatic and heterocyclic compounds are indispensable structural units for both the chemist and the biochemist.Quinoxalines constitute the basis of many insecticides, fungicides, herbicides and anthelmintics, as well as being important in human health and as receptor antagonists. 1,2 A number of methods have been developed for the synthesis of substituted quinoxalines involving condensation of 1,2-diamines with α-diketones, 3 1,4-addition of 1,2-diamines to diazenylbutenes, 4 oxidation-trapping of α-hydroxy ketones with 1,2-diamine. 5Other recently, reported methods accomplished the synthesis of quinoxaline by the reaction of 1,2-amines with phenacyl bromides in solid-phase, 6 or using heterogenous catalyst like HClO 4 •SiO 2 . 7Nevertheless, most of these methods suffer from unsatisfactory yields, difficult experimental procedures, expensive and detrimental metal precursors and harsh reaction conditions.Therefore, the development of improved methods for the synthesis of quinoxaline derivatives has acquired relevance to current research.