反应详情

温度

50 °C

N-Phenyl-β-alanine ethyl ester (24,25 g) is dissolved in benzene (60 ml), and thereto is added dropwise diketene (12 ml) at 70° C. The mixture is refluxed overnight. The mixture is distilled to remove the solvent to give crude N-phenyl-N-methoxycarbonylmethylcarbonyl-β-alanine ethyl ester (37.23 g). Said crude compound is dissolved in methanol (70 ml), and the mixture is added dropwise to a solution of sodium methoxide (prepared from 3.90 g of sodium) in methanol (70 ml) at 50° C. The mixture is stirred at 50° C. for 2 hours, and distilled to remove the solvent. The residue is dissolved in water, and the aqueous solution is extracted with ethyl acetate. The aqueous layer is neutralized with 10% HCl, and 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 purified by silica gel column chromatography (solvent, ethyl acetate:n-hexane=1:2) to give 1-phenyl-3-acetyl-2,4-dioxopiperidine (23.87 g, 81.6%) as oil.

1. temperatureThe mixture is refluxed overnight
2. distillationThe mixture is distilled
3. customto remove the solvent
4. customto give crude N-phenyl-N-methoxycarbonylmethylcarbonyl-β-alanine ethyl ester (37.23 g)
5. distillationdistilled
6. customto remove the solvent
7. dissolutionThe residue is dissolved in water
8. extractionthe aqueous solution is extracted with ethyl acetate
9. extractionextracted with ethyl acetate
10. washThe extract is washed with a saturated sodium chloride solution
11. customdried
12. distillationdistilled
13. customto remove the solvent
14. customThe residue is purified by silica gel column chromatography (solvent, ethyl acetate:n-hexane=1:2)