反应详情

温度

25 °C

To a 500 mL round bottom flask was added L-aspartic acid ((S)-aspartic acid, 25 g, 188 mmol) and 245 mL of 5 N HBr. The reaction was cooled in an ice bath to 0-50° C., followed by the dropwise addition of sodium nitrite (20.7 g, 301 mmol) in 75 mL of water over five hours. The temperature was maintained below 50° C. during the addition. After the addition was complete, the reaction was allowed to stir for 12 hours at 23-25° C. The reaction was diluted with diethyl ether (120 mL). The aqueous layer was removed and the organic phase was washed with 1 N HCl (100 mL). The combined aqueous phases were washed with EtOAc (100 ml). The combined organic extracts were dried (MgSO4), filtered and concentrated under reduced pressure to leave the product as a slightly yellow solid. The solid was recrystallized from EtOAc (˜100 mL) and hexanes (˜10 mL) to obtain the product (19.03 g, 97 mmol, 51%) as a white crystalline solid.

1. temperatureThe temperature was maintained below 50° C. during the addition
2. additionAfter the addition
3. customThe aqueous layer was removed
4. washthe organic phase was washed with 1 N HCl (100 mL)
5. washThe combined aqueous phases were washed with EtOAc (100 ml)
6. dry with materialThe combined organic extracts were dried (MgSO4)
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customto leave the product as a slightly yellow solid
10. customThe solid was recrystallized from EtOAc (˜100 mL) and hexanes (˜10 mL)