反应详情

温度

0 °C

This procedure may be carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. is added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction is stirred 1 h at 0° C., then 2 h at room temperature. The solvents are removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm.

1. custom2 h
2. customat room temperature
3. customThe solvents are removed under reduced pressure
4. distillationthe residue was short-path distilled at pump vacuum (about 0.5 mm)
5. customThe fraction collected at 100° C.-120° C.