反应详情

A solution of ethyl glycolate (4.6 g, 44 mmol) in DMF (50 mL) was cooled to 0° C. and′ sodium bis(trimethylsilyl)amide (1.0 M in THF, 53 mL, 53 mmol) was slowly added. The reaction was stirred for 15 minutes and 1,4-dibromobutane (5.6 mL, 48.4 mmol) was added. The reaction was warmed to room temperature and was stirred for 24 h. Et2O was added, and the organic solution was washed consecutively with HCl (1N, 3×), water (3×), and brine (1×). The organic solution was dried (Na2SO4), filtered, and concentrated. Attempted vacuum distillation removed a majority of the impurities and provided a mixture of product and 1,4-dibromobutane (3.539 g). Flash chromatography (9:1 hexanes:EtOAc) of this material provided (4-bromo-butoxy)-acetic acid ethyl ester (1.862 g). 1H NMR (400 MHz, CDCl3) δ 4.19 (q, 2H), 4.04 (s, 2H), 3.54 (t, 2H), 3.45 (t, 2H), 1.97 (m, 2H), 1.75 (m, 2H), 1.26 (t, 3H); MS 239.1 (M+).

1. stirringwas stirred for 24 h
2. washthe organic solution was washed consecutively with HCl (1N, 3×), water (3×), and brine (1×)
3. dry with materialThe organic solution was dried (Na2SO4)
4. filtrationfiltered
5. concentrationconcentrated
6. distillationvacuum distillation
7. customremoved a majority of the impurities
8. customprovided