11H-indeno[1,2-b]quinoxalin-11-one (4a, 0.23 g, 1.0 mmol) was mixed with hydroxylamine hydrochloride (0.35 g, 5.0 mmol) in ethanol (EtOH, 5.0 mL) and reacted at reflux for 6 hours (the reaction progression was monitored by thin layer chromatography (TLC)). Upon completion of the reaction, the mixture was cooled to room temperature and poured into water. The resulting precipitate was collected by filtration and recrystallized from ethanol to afford the target product 11H-indeno[1,2-b]quinoxalin-11-one oxime (5a, 0.23 g, 94% yield) as a white solid. Melting point: 274-276°C (recrystallized in ethanol, decomposed). Nuclear magnetic resonance hydrogen spectrum (1H NMR, 400MHz, DMSO-d6): δ 7.67-7.72 (m, 2H, ArH), 7.78-7.85 (m, 2H, ArH), 8.10-8.13 (m, 2H, ArH), 8.14-8.17 (m, 1H, ArH), 8.50-8.53 (m, 1H, ArH). 13.48 (s, 1H, NOH). Nuclear magnetic resonance carbon spectrum (13C NMR, 100 MHz, DMSO-d6): δ 122.26, 128.76, 129.30, 129.87, 129.99, 130.58, 132.09, 132.56, 133.07, 135.99, 141.56, 141.85, 147.18, 150.81, 152.89. electrospray mass spectrometry. 152.89. electrospray ionization mass spectrometry (ESIMS): [M+H]+ m/z 248.01. Calculated values for elemental analysis (C15H9N3O-0.2H2O): C 71.81%, H 3.78%, N 16.75%; measured values: C 71.47%, H 3.65%, N 16.80%.
![11H-INDENO[1,2-B]QUINOXALIN-11-ONE](/CAS/GIF/6954-91-2.gif)
