反应详情

Ethyl (N-benzylcarbamoyl)acetate (39.00 g) and carbon disulfide (14.03 g) are dissolved in dimethylsulfoxide (390 ml). A solution of potassium hydroxide (21.52 g) in water (39 ml) is added dropwise to the mixture at 20° to 40° C. The mixture is stirred at the same temperature for 30 minutes, and then cis-1,2-dichloroethylene (17.84 g) is added dropwise thereto. The mixture is stirred at 50° C. for 5 hours. Cis-1,2-dichloroethylene (3.24 g) is further added to the mixture 3 hours after the commencement of the reaction. After cooling, the mixture is poured into water, and the aqueous solution is extracted with ethyl acetate. The extract is washed with water, dried and then evaporated to remove the solvent. The residue is purified by silica gel column chromatography (solvent: n-hexane-ethyl acetate=2:1), and then recrystallized from a mixture of n-hexane and ethyl acetate, whereby ethyl 2-(1,3-dithiol-2-ylidene)-2-(N-benzylcarbamoyl)acetate (33.77 g) is obtained as pale yellow prisms. Yield: 62.8%.

1. stirringThe mixture is stirred at 50° C. for 5 hours
2. customafter the commencement of the reaction
3. temperatureAfter cooling
4. extractionthe aqueous solution is extracted with ethyl acetate
5. washThe extract is washed with water
6. customdried
7. customevaporated
8. customto remove the solvent
9. customThe residue is purified by silica gel column chromatography (solvent: n-hexane-ethyl acetate=2:1)
10. customrecrystallized from a mixture of n-hexane and ethyl acetate