反应详情

To a stirred mixture of sodium borohydride (1.11 g, 29.3 mmol) in ethanol (10 mL) at room temperature was added a solution of the (6-bromo-benzothiazol-2-yl)-acetic acid ethyl ester (2.2 g, 7.3 mmol) in THF (25 mL) at 23-28° C. The mixture was stirred at room temperature for 15 hr, cooled to 3° C. and quenched with 20 mL water at 3-5° C. The product was extracted with 40 mL methylene chloride, washed with 20 mL 15% NaCl and concentrated to crude oil. The crude product was purified by column chromatography (silica gel, 10:90 MeOH:CHCl3) to give the pure 2-(6-Bromo-benzothiazol-2-yl)-ethanol: 1H NMR (CDCl3, 400 MHz) δ 3.30 (t, 2H, J=6 Hz), 4.11 (t, 2H, J=6 Hz), 7.54 (dd, 1H, J=5, 2 Hz), 7.78 (d, 1H, J=5 Hz), 7.95 (d, 1H, J=2 Hz). 13C NMR (CDCl3, 400 MHz) δ 36.7, 60.8, 118.3, 123.3, 129.2, 136.1, 151.3, 169.5; (DCl/NH3) m/z 258, 260 (M+H)+.

1. temperaturecooled to 3° C.
2. customquenched with 20 mL water at 3-5° C
3. extractionThe product was extracted with 40 mL methylene chloride
4. washwashed with 20 mL 15% NaCl
5. concentrationconcentrated to crude oil
6. customThe crude product was purified by column chromatography (silica gel, 10:90 MeOH:CHCl3)