A recyclable copper catalysis in quinoxaline synthesis from α-hydroxyketones and o-phenylenediamines

o-Phenylenediamines react with α-hydroxyketones in toluene at 100 °C in the presence of a catalytic amount of a copper catalyst along with MS 4A under O2 atmosphere to afford the corresponding quinoxalines in high yields. The catalytic system could be easily recovered and reused several times without any loss of catalytic activity.