反应详情

温度

85 °C

A solution of (S)-8-bromo-3-methyl-3,4-dihydroquinoxalin-2(1H)-one (17 g, 70.5 mmol), MeOH (141 mL), and 1.0 N aq. NaOH (141 mL, 141 mmol) was stirred at 85° C. in a three-necked round-bottom flask fitted with a septum, reflux condenser, and addition funnel. A mixture of H2O2 (30% in water; 25.2 mL, 247 mmol) and deionized water (10 mL) was then added, dropwise via the addition funnel, over 45 min, and the resulting mixture was heated at 85° C. for 17 h. The mixture was cooled to RT, 5 N aq. HCl (36 mL) was added, and the resulting slurry was extracted with 10% MeOH/DCM (3×150 mL). The combined extracts were dried over Na2SO4, filtered, and concentrated in vacuo to give 8-bromo-3-methylquinoxalin-2(1H)-one (126d; 13.16 g, 55.1 mmol, 78% yield) as a tan solid, which was used without further purification in the subsequent step: 1H NMR (400 MHz, CDCl3) δ ppm 9.03 (1H, s), 7.77 (1H, d, J=8.2 Hz), 7.67 (1H, d, J=7.6 Hz), 7.22 (1H, t, J=7.8 Hz), 2.61 (3H, s). m/z (ESI, +ve) 239.0 (M+H)+.

1. customfitted with a septum
2. temperaturereflux
3. additioncondenser, and addition funnel
4. additionwas then added, dropwise via the addition funnel, over 45 min
5. temperatureThe mixture was cooled to RT
6. extractionthe resulting slurry was extracted with 10% MeOH/DCM (3×150 mL)
7. dry with materialThe combined extracts were dried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated in vacuo