Ionic liquid-catalysed regioselective oxygenation of quinoxalin-2(1H)-ones under visible-light conditions

Abstract

Ionic liquid-catalysed oxygenation of quinoxalin-2(1H)-one utilizing aerobic oxygen as a green oxidant under visible light conditions at room temperature has been described. Various N-1-alkyl and aryl-substituted quinoxalin-2(1H)-ones provided good yields of the desired products. The ionic-liquid tetramethylammonium hydroxide (TMAH) employed is readily available and promotes the oxygenation under additive and base-free conditions. The present procedure illustrates the applicability at gram scale reactions and showcases the subsequent conversion of the target product into glycogen phosphorylase inhibitors.