反应详情

温度

70 °C

(3,4-Dichloro-phenyl)-oxo-acetic acid ethyl ester (1.08 g, 4.37 mmol) was stirred in ethanol (9.7 mL) and warmed in a 70° C. oil bath. O-Cyclopentyl-hydroxylamine (prepared as in Example 1, 722 mg, 5.25 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; 33% methylene chloride/hexanes) afforded (E)-cyclopentyloxyimino-(3,4-dichloro-phenyl)-acetic acid ethyl ester (371 mg, 26%) as a clear, colorless oil: H1-NMR (400 MHz, CDCl3) δ=1.37 (3H, t, J=7.1 Hz), 1.63 (4H, m), 1.85 (4H, m), 4.36 (2H, q, J=7.1 Hz), 4.94 (1H, m), 7.26 (1H, dd, J=8.3 Hz, J=1.9 Hz), 7.46 (1H, d, J=8.3 Hz), 7.54 (1H, d, J=1.9 Hz).

1. temperatureto cool
2. concentrationconcentrated in vacuo
3. customPurification by flash column chromatography (Merck silica gel 60, 40-63 μm; 33% methylene chloride/hexanes)