反应详情

A solution of 4.65 g of 2',4'-dichloro-2-(3-pyridyl)acetophenone in 25 ml of ethanol is treated with 2.70 g of anhydrous sodium carbonate and 2.63 g of O-isobutylhydroxylamine hydrochloride and the reaction mixture is then heated to reflux temperature with stirring. After 4 hours, it is poured onto ice and extracted with ethyl acetate. The organic phase is washed with water, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. 2',4'-Dichloro-2-(3-pyridyl)acetophenone O-isobutyloxime is obtained as an E/Z isomer mixture in the form of a brownish oil. In the chromatographic separation on silica gel using n-hexane/ethyl acetate (7:3), the E isomer [1H-NMR (CDCl3, 200 MHz): 2.055 ppm (heptet, HC(CH3)2)] is eluted first and then the Z isomer [1H-NMR (CDCl3, 200 MHz): 1.928 ppm (heptet, HC(CH3)2)].

1. temperaturethe reaction mixture is then heated
2. temperatureto reflux temperature
3. additionit is poured onto ice
4. extractionextracted with ethyl acetate
5. washThe organic phase is washed with water
6. dry with materialdried over anhydrous magnesium sulfate
7. concentrationconcentrated under reduced pressure