Hydrochloric Acid → Ethyl 3-bromo-2-hydroxypropanoate
反応式
C([BH3-])#N.[Na+].[Br:5][CH2:6][C:7](=[O:13])[C:8]([O:10][CH2:11][CH3:12])=[O:9].Cl>CO.C(OCC)C>[Br:5][CH2:6][CH:7]([OH:13])[C:8]([O:10][CH2:11][CH3:12])=[O:9]C([BH3-])#N.[Na+].[Br:5][CH2:6][C:7](=[O:13])[C:8]([O:10][CH2:11][CH3:12])=[O:9].Cl>CO.C(OCC)C>[Br:5][CH2:6][CH:7]([OH:13])[C:8]([O:10][CH2:11][CH3:12])=[O:9]To a solution of sodium cyanoborohydride (17.72 g, 282.0 mmol) in anhydrous MeOH (160 mL) under an atmosphere of nitrogen was added ethyl bromopyruvate (32.25 mL, 256.4 mmol, 80-85%) in anhydrous MeOH (160 mL). The mixture was treated with 1N HCl in diethyl ether to pH 4 and stirred for 1 h at 0° C. The solvent was removed in vacuo, and the resulting slurry was partitioned between diethyl ether and saturated aqueous NH4Cl solution. The aqueous layer was extracted several times into diethyl ether, and the organic extracts were combined, dried over Na2SO4 and concentrated to a pale yellow oil. The oil was diluted with diethyl ether (300 mL) and chilled to −78° C. for 1 hour. The resulting precipitate was collected by filtration to afford the alcohol as a white solid. 1H NMR (400 MHz, d6-DMSO) δ 5.99 (dd, J=1.2, 6.0 Hz, 1H), 4.43-4.39 (m, 1H), 4.21-4.08 (m, 2H), 3.69 (d, J=0.8 Hz, 2H), 1.23-1.18 (m, 3H).
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