反应详情

温度

70 °C

To a solution of the product of step C (2.3 g, 5.35 mmol) in dimethylformamide (11 mL) was added sodium azide (1.2 g, 18.73 mmol) at ambient temperature. The reaction mixture was heated at 70° C. for 2 h, cooled and quenched with water then extracted with ethyl acetate (2×15 mL). The combined organic extracts were dried over Na2SO4 and concentrated in vacuo to give the crude product which was purified by column chromatography (SiO2, 4:1 hexanes/ethyl acetate) providing 2-(2-azidoethyl)-5-bromo-7-chlorobenzofuran (1.2 g, 75%) as an off-white solid: 1H NMR (CDCl3, 400 MHz) δ 7.52-7.49 (m, 1H), 7.37-7.35 (m, 1H), 6.50 (s, 1H), 3.67 (t, J=6.8 Hz, 2H), 3.07 (t, J=6.8 Hz, 2H).

1. temperaturecooled
2. customquenched with water
3. extractionthen extracted with ethyl acetate (2×15 mL)
4. dry with materialThe combined organic extracts were dried over Na2SO4
5. concentrationconcentrated in vacuo
6. customto give the crude product which
7. customwas purified by column chromatography (SiO2, 4:1 hexanes/ethyl acetate)