反应详情

A solution of 13.3 g of 2',4'-dichloro-2-(3-pyridyl)-acetophenone in 40 ml of ethanol is treated with 10 g of sodium carbonate and 8.3 g of O-methylhydroxylamine hydrochloride; the mixture is subsequently heated at reflux temperature while stirring. After 4 hours, the mixture is poured onto ice and extracted with ethyl acetate. The organic phase is washed, dried over sodium sulfate and concentrated under reduced pressure to yield 2',4'-dichloro-2-(3-pyridyl)-acetophenone O-methyl oxime as the E,Z-isomer mixture in the form of a yellowish oil. Chromatographic separation on silica gel with n-hexane/ethyl acetate (4:1) as the eluant yields firstly the E-isomer (nD20 =1.5845) and then the Z-isomer (nD20 =1.5745).

1. temperaturethe mixture is subsequently heated
2. temperatureat reflux temperature
3. additionthe mixture is poured onto ice
4. extractionextracted with ethyl acetate
5. washThe organic phase is washed
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated under reduced pressure