反应详情

To a solution of ethyl 2-vinyloxyimino-3,3-ethylenedioxybutyrate (syn isomer)(15 g) and benzyl-triethylammonium chloride (164 mg) in a mixture of methylene chloride (13 ml), bromoform (11.4 ml) and ethanol (0.65 ml) was added 50% aqueous solution of sodium hydroxide (105 ml) under ice-cooling. The mixture was stirred for 1 hour at the same temperature and allowed to be stirred at ambient temperature overnight. The mixture was extracted with diethyl ether. The extract was washed with water, dried over magnesium sulfate and concentrated in vacuo. The residue was subjected to column chromatography on silica gel using a mixture of chloroform and ethyl acetate (4:1 V/V) as an eluent to give ethyl 2-(2,2-dibromocyclopropyloxyimino)-3,3-ethylenedioxybutyrate (syn isomer)(15.4 g) as an oil.

1. temperaturecooling
2. stirringto be stirred at ambient temperature overnight
3. extractionThe mixture was extracted with diethyl ether
4. washThe extract was washed with water
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated in vacuo
7. additiona mixture of chloroform and ethyl acetate (4:1 V/V) as an eluent