Abstract 3-Benzoyl-1, 2-dihydroquinoxalin-2-one reacts with hydrazine and thiosemicarbazide to give the corresponding hydrazone and thiosemicarbazone. The reaction with arylhydrazines yields 3-(α-arylazobenzylidene)-1, 2, 3, 4-tetrahydroquinoxalin- 2-ones which are tautomeric to the respective arylhydrazones. On heating in boiling acetic acid, the products of both types undergo intramolecular cyclocondensation with formation ...