Scope of N-unsubstituted quinoxalin-2(1H)-one with diverse phenylhydrazines.^a,b.

^aReaction conditions: a mixture of 1m (0.5 mmol) and 2a–f (0.75 mmol) in the presence of K₂S₂O₈ (1.5 mmol) was stirred in acetonitrile at 50 °C for 6–9 hours under air exposure.

^bIsolated yields.