反应详情

温度

70 °C

(3-Chloro-4-methanesulfonyl-phenyl)-oxo-acetic acid methyl ester (prepared as in Example 1, 1.2 g, 4.34 mmol) was stirred in methanol (9 mL) and warmed in a 70° C. oil bath. O-Cyclohexyl-hydroxylamine hydrochloride (0.811 g, 5.43 mmol) was added. After 2 h, the reaction mixture was allowed to cool and concentrated in vacuo. Purification by flash column chromatography (Merck silica gel 60, 40-63 μm; 20% ethyl acetate/hexanes to 50% ethyl acetate/hexanes) afforded (E)-(3-chloro-4-methanesulfonyl-phenyl)-cyclohexyloxyimino-acetic acid methyl ester as a white solid (552 mg, 34%): H1-NMR (400 MHz, CDCl3) δ=1.34 (3H, m), 1.51 (3H, m), 1.68 (2H, m), 1.96 (2H, m), 3.31 (3H, s), 3.91 (3H, s), 4.39 (1H, m), 7.51 (1H, dd, J=8.1 Hz, J=1.5 Hz), 7.62 (1H, d, J=1.5 Hz), 8.18 (1H, d, J=8.1 Hz).

1. temperatureto cool
2. concentrationconcentrated in vacuo
3. customPurification by flash column chromatography (Merck silica gel 60, 40-63 μm; 20% ethyl acetate/hexanes to 50% ethyl acetate/hexanes)