反应详情

Ethyl 2-(2,3-dihydro-1,4-oxathiin-6-yl)-2-n-propoxyiminoacetate (mixture of syn isomer and anti isomer, 1 g.) was added to a mixture of methanol (10 ml.) and 1 N aqueous solution of sodium hydroxide (6 ml.), and stirred at room temperature for 18 hours. After distilling off the methanol from the resultant solution in vacuo, a saturated aqueous solution of sodium bicarbonate (15 ml.) and ethyl acetate (15 ml.) were added to the residue and shaken sufficiently. The aqueous layer was separated, adjusted to pH 1.0 with 10% hydrochloric acid and extracted with ethyl acetate (20 ml.). The extract was washed with water, dried over magnesium sulfate and concentrated in vacuo. The residue was triturated with a mixture of n-hexane and diethyl ether (1:1). The precipitates were collected by filtration and washed with the same mixture to give 2-(2,3-dihydro-1,4-oxathiin-6-yl)-2-n-propoxyiminoacetic acid (syn isomer, 0.30 g.).

1. distillationAfter distilling off the methanol from the resultant solution in vacuo
2. additiona saturated aqueous solution of sodium bicarbonate (15 ml.) and ethyl acetate (15 ml.) were added to the residue
3. stirringshaken sufficiently
4. customThe aqueous layer was separated
5. extractionextracted with ethyl acetate (20 ml.)
6. washThe extract was washed with water
7. dry with materialdried over magnesium sulfate
8. concentrationconcentrated in vacuo
9. customThe residue was triturated with a mixture of n-hexane and diethyl ether (1:1)
10. filtrationThe precipitates were collected by filtration
11. washwashed with the same mixture