反应详情

温度

70 °C

(4-Methylsulfonyl-phenyl)-oxo-acetic acid ethyl ester (218 mg, 0.85 mmol) was stirred in ethanol (1.7 mL) and warmed in a 70° C. oil bath. O-Cyclopentyl-hydroxylamine (prepared as in Example 1, 146 mg, 1.06 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 □m; 30% ethyl acetate/hexanes to 75% ethyl acetate/hexanes) afforded (E)-cyclopentyloxyimino-(4-methanesulfonyl-phenyl)-acetic acid ethyl ester (60 mg, 21%) as a clear, colorless film containing an unidentified impurity: LC-MS (ESI) m/e calcd for C16H21NO5S [M+] 339.11, found 340 [M+H+].

1. temperatureto cool
2. concentrationconcentrated in vacuo
3. customPurification by flash column chromatography (Merck silica gel 60, 40-63 □m; 30% ethyl acetate/hexanes to 75% ethyl acetate/hexanes)