反应详情

温度

70 °C

A 500 mL round-bottom flask was charged with crude 3-bromo-1-(6-bromo-2-methylpyridin-3-yl)pyrrolidin-2-one from step A (18.5 g), THF (50 mL), 18-Crown-6 (576 mg, 2.18 mmol) and KOAc (12.84 g, 131 mmol). The mixture was heated at 70° C. under argon overnight. After cooling the reaction mixture to room temperature, ethyl acetate (50 mL) was added. The organic layer was separated and washed with water (50 mL), brine (50 mL), dried over MgSO4, filtered and concentrated to a dark solid, which was purified by flash chromatography (silica gel, 20-100% ethyl acetate/hexane) to give 1-(6-bromo-2-methylpyridin-3-yl)-2-oxopyrrolidin-3-yl acetate (8.9 g, 65% yield for two steps) as white solid. 1H NMR (400 MHz, CHLOROFORM-d) δ 7.38 (q, J=8.3 Hz, 3H), 5.43 (t, J=8.2 Hz, 1H), 3.47-4.03 (m, 3H), 2.62-2.90 (m, 1H), 2.38-2.56 (m, 4H), 2.06-2.32 (m, 5H); MS (ESI) 314 (M+H).

1. temperatureAfter cooling the reaction mixture to room temperature
2. customThe organic layer was separated
3. washwashed with water (50 mL), brine (50 mL)
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated to a dark solid, which
7. customwas purified by flash chromatography (silica gel, 20-100% ethyl acetate/hexane)