反应详情

温度

0 °C

To a solution of N-(2,3-dihydrobenzo[b][1,4]dioxin-5-yl)acetamide (5.5 g, 28.5 mmol) in chloroform (20 mL) cooled at −20° C. was slowly added a solution of bromine (1.6 mL, 30 mmol) in chloroform (5 mL) so that the reaction temperature was maintained below −10° C. The reaction was stirred at 0° C. for 10 minutes, and then quenched immediately with water. The mixture was extracted with dichloromethane; the combined extracts were washed with saturated sodium bicarbonate and brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was subjected to silica gel chromatography (dichloromethane) to afford the product N-(8-bromo-2,3-dihydrobenzo[b][1,4]dioxin-5-yl)acetamide (5 g, yield 64%). 1H NMR (400 MHz, CDCl3) δ ppm 9.23 (s, 1H), 7.46-7.48 (d, 1H, J=8.8 Hz), 7.04-7.06 (d, 1H, J=9.2 Hz), 4.32-4.40 (m, 4H), 2.07 (s, 3H).

1. temperaturewas maintained below −10° C
2. customquenched immediately with water
3. extractionThe mixture was extracted with dichloromethane
4. washthe combined extracts were washed with saturated sodium bicarbonate and brine
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure