反应详情

A mixture of 6,7-dichloro-2,3-dimethoxy-5-methylquinoxaline (from step (f), 22.0 g, 80.5 mmol), N-bromosuccinimide (17.2 g, 96.6 mmol) and α,α-azoisobutyronitrile (1.3 g, 8.0 mmol) was heated at reflux in 1,1,1-trichloroethane (400 ml) for 4 h under irradiation from a 500 W sunlamp. The mixture was cooled, silica gel (50 g, 60-230 m) was added, and the solvent was removed under reduced pressure. The residue was applied to the top of a silica gel chromatography column, and the product was eluted using a hexane/ethyl acetate gradient. The product was triturated with hexane to give 5-bromomethyl-6,7-dichloro-2,3-dimethoxyquinoxaline (25.3 g, 87%) as a fluffy white solid. Found: C, 37.72; H, 2.40; N, 7.40; C11H9 BrCl2N2O2 requires C,37.53; H, 2.58; N, 7.96%.

1. temperaturewas heated
2. temperatureThe mixture was cooled
3. additionsilica gel (50 g, 60-230 m) was added
4. customthe solvent was removed under reduced pressure
5. washthe product was eluted
6. customThe product was triturated with hexane