An efficient synthesis of quinoxaline derivatives: one-pot threecomponent reaction of arylglyoxal, o- phenylenediamine, Meldrum s acid as catalyst

Functionalized quinoxalines represent an important class of nitrogen-containing heterocycles as they constitute useful intermediates in organic synthesis and are useful dyes [1]. Quinoxaline derivatives have different pharamacological activities such as bacteriocides and insecticides, antibacterial, antifungal, antitubercular and analgesic [2]. Quinoxalines derivatives was prepared via stirring of Meldrum s acid as catalyst 1 and arylglyoxal 2 with o- phenylenediamine 3 in ethanol at room temperature for 1 h. After completion of the reaction, determined by TLC, the product 4 was precipitated from the reaction mixture. The precipitate was filtered and recrystallized from ethanol (Fig 1). The advantages of this method are base free, the high yields of products, short reaction times, easy of the work up, and green solvent. Quinoxaline derivatives were identified by spectroscopy techniques such as 1H-NMR, 13C-NMR, IR.