Visible light-induced recyclable g-C3N4 catalyzed C–H/N–H cross-dehydrogenative coupling amination of Quinoxalin-2(1H)-ones

The development of efficient and sustainable methods for constructing carbon-nitrogen (C–N) bonds is of great importance in organic synthesis, particularly for the preparation of nitrogen-containing compounds with pharmaceutical relevance. Herein, a novel photocatalytic strategy utilizing sustainable graphitic carbon nitride (g-C₃N₄) for the cross-dehydrogenative coupling (CDC) amination of quinoxalin-2(1H)-ones under visible light and mild conditions is described. Utilizing g-C₃N₄ as a heterogeneous photocatalyst, a wide range of 3-aminoquinoxalin-2(1H)-one derivatives were synthesized in moderate to good yields (up to 89 %). The catalyst demonstrated remarkable stability and recyclability, maintaining its photocatalytic activity after five catalytic cycles. Mechanistic investigations indicated that the reaction follows a radical pathway. This method offers a green, sustainable alternative to metal-catalyzed CDC amination, with easy catalyst recovery showcasing g-C₃N₄'s potential as an eco-friendly photocatalyst.