反应详情

To a stirred solution of 2-mercaptoethanol (7.8 g.) and ethyl 2-(2-chloroacetyl)-2-methoxyiminoacetate (2.08 g.) in dry chloroform (200 ml.) was added a solution of triethylamine (11 g.) in dry chloroform (30 ml.) at 20° C., and stirred at the same temperature for 3 hours. The resultant solution was washed with 10% hydrochloric acid twice, a saturated aqueous solution of sodium hydroxide twice and water twice in turn, and dried over magnesium sulfate. The solution was concentrated in vacuo at 40° C., and the residue was dissolved in dry toluene (200 ml.). After adding p-toluenesulfonic acid (3 g.) to the solution, the solution was heated under reflux for 30 minutes while removing the produced water. The resultant solution was allowed to cool at room temperature and treated with activated charcoal, and then ethyl acetate (150 ml.) was added thereto. The solution was washed with a saturated aqueous solution of sodium bicarbonate and water twice in turn dried over magnesium sulfate, and then concentrated in vacuo at 40° C. to give ethyl 2-(2,3-dihydro-1,4-oxathiin-6-yl)-2-methoxyiminoacetate (mixture of syn isomer and anti isomer, 18.5 g.), yellow oil.

1. washThe resultant solution was washed with 10% hydrochloric acid twice
2. dry with materiala saturated aqueous solution of sodium hydroxide twice and water twice in turn, and dried over magnesium sulfate
3. concentrationThe solution was concentrated in vacuo at 40° C.
4. dissolutionthe residue was dissolved in dry toluene (200 ml.)
5. additionAfter adding p-toluenesulfonic acid (3 g.) to the solution
6. temperaturethe solution was heated
7. temperatureunder reflux for 30 minutes
8. customwhile removing the produced water
9. additiontreated with activated charcoal
10. additionethyl acetate (150 ml.) was added
11. washThe solution was washed with a saturated aqueous solution of sodium bicarbonate and water twice in turn
12. dry with materialdried over magnesium sulfate
13. concentrationconcentrated in vacuo at 40° C.