反应详情

Ethyl chlorocarbonate (2.0 ml) was added dropwise to a mixture of cinnamic acid (2.96 g), dichloromethane (60 ml) and triethylamine (2.8 ml) under cooling with ice-sodium chloride and stirring, and the whole mixture was stirred for 10 minutes. L-Aspartic acid β-methyl ester hydrochloride (3.67 g) was added and triethylamine (5.6 ml) was further added dropwise. The resulting mixture was stirred at room temperature for 40 minutes, washed with 2N hydrochloric acid and water and dried over anhydrous magnesium sulfate. The solvent was then distilled off. To the thus-obtained N-cynnamoyl-L-aspartic acid β-methyl ester were added acetic anhydride (15 ml), triethylamine (15 ml) and 4-dimethylaminopyridine (0.2 g) and the mixture was stirred for 30 minutes, poured into water, stirred for 10 minutes for decomposition and extracted with ethyl acetate. The ethyl acetate layer was washed with diluted hydrochloric acid, water, aqueous sodium hydrogen carbonate and water, and dried over anhydrous magnesium sulfate. The solvent was distilled off and the residue was treated with isopropyl ether to give methyl 3-cinnamoylamino- 4-oxovalerate as crystals; yield 2.65 g (48.1%). Recrystallization from ethyl ether gave colorless needles melting at 82°-83° C.

1. stirringthe whole mixture was stirred for 10 minutes
2. stirringThe resulting mixture was stirred at room temperature for 40 minutes
3. washwashed with 2N hydrochloric acid and water
4. dry with materialdried over anhydrous magnesium sulfate
5. distillationThe solvent was then distilled off
6. additionTo the thus-obtained N-cynnamoyl-L-aspartic acid β-methyl ester were added acetic anhydride (15 ml), triethylamine (15 ml) and 4-dimethylaminopyridine (0.2 g)
7. stirringthe mixture was stirred for 30 minutes
8. additionpoured into water
9. stirringstirred for 10 minutes for decomposition
10. extractionextracted with ethyl acetate
11. washThe ethyl acetate layer was washed with diluted hydrochloric acid, water, aqueous sodium hydrogen carbonate and water
12. dry with materialdried over anhydrous magnesium sulfate
13. distillationThe solvent was distilled off
14. additionthe residue was treated with isopropyl ether