反应详情

To a mixture of 9-chloromethyl-7-oxo-2,3,6,7-tetrahydro[1,4]dioxino[2,3-g]quinoline-8-carboxylic acid methyl ester (Intermediate 5, 25 g), in 1,2-dichloroethane (DCE, 90 mL) is added a solution of phosphorus oxybromide (44 g, 2 eq) in DCE (90 mL). The resultant mixture is heated at reflux for 4.0 h, and then cooled to <15° C. Ethanol (91 mL, 20.0 eq) is added while keeping the temp <20° C. The mixture is then allowed to warm to room temperature and stirred overnight. The mixture is filtered and the solid is washed with DCE (30 mL). The solid is dried under high vacuum (about 1 mm Hg) at room temperature overnight to yield 7-bromo-9-bromomethyl-2,3-dihydro[1,4)]dioxino[2,3-g]quinoline-8-carboxylic acid methyl ester hydrobromic acid salt as a yellow solid. HRMS (EI+): calc for C15H13Br2NO4: 428.9211, Found: 428.9238.

1. temperatureat reflux for 4.0 h
2. temperaturecooled to <15° C
3. customthe temp <20° C
4. filtrationThe mixture is filtered
5. washthe solid is washed with DCE (30 mL)
6. customThe solid is dried under high vacuum (about 1 mm Hg) at room temperature overnight