反应详情

A mixture of ethyl 2-methoxyimino-3-oxo-4-chlorobutyrate (syn isomer, 41 g), ethylene glycol (24.6 g), p-toluenesulfonic acid (2.0 g) and toluene (250 ml) was heated for 20 hours under reflux while removing water. The reaction mixture was cooled to ambient temperature, washed with a saturated aqueous solution of sodium bicarbonate, a saturated aqueous solution of sodium chloride in turn, dried over magnesium sulfate and then the solvents were removed. The residue was distilled under reduced pressure to give ethyl 2-methoxyimino-3,3-ethylenedioxy-4-chlorobutyrate (syn isomer, 24.4 g), bp 103°-110° C./2 mmHg.

1. temperaturewas heated for 20 hours
2. temperatureunder reflux
3. customwhile removing water
4. washwashed with a saturated aqueous solution of sodium bicarbonate
5. dry with materiala saturated aqueous solution of sodium chloride in turn, dried over magnesium sulfate
6. customthe solvents were removed
7. distillationThe residue was distilled under reduced pressure