反应详情

Ethyl 1-benzyl-5-(1,3-dithiol-2-ylidene)-3-methyl-4,6-dioxopiperidine-3-carboxylate (245 mg) is dissolved in ethanol (5 ml), and thereto is added a 10% sodium hydroxide solution (2.5 ml). The mixture is stirred at room temperature overnight. The mixture is acidified with 10% HCl, and poured into water. The aqueous solution is extracted with ethyl acetate. The extract is washed with a saturated sodium chloride solution, dried and then distilled to remove the solvent. The residue is dissolved in ethanol (20 ml) and the solution is refluxed for one hour. The mixture is distilled to remove the solvent. The residue is purified by silica gel column chromatography (solvent, ethyl acetate:n-hexane=1:1), and is recrystallized from a mixture of ethyl acetate and n-hexane to give 1-benzyl-3-(1,3-dithiol-2-ylidene)-5-methyl-2,4-dioxopiperidine (138 mg, 69.1%) as pale yellow needles, m.p. 168°-170° C.

1. extractionThe aqueous solution is extracted with ethyl acetate
2. washThe extract is washed with a saturated sodium chloride solution
3. customdried
4. distillationdistilled
5. customto remove the solvent
6. dissolutionThe residue is dissolved in ethanol (20 ml)
7. temperaturethe solution is refluxed for one hour
8. distillationThe mixture is distilled
9. customto remove the solvent
10. customThe residue is purified by silica gel column chromatography (solvent, ethyl acetate:n-hexane=1:1)
11. customis recrystallized from a mixture of ethyl acetate and n-hexane