反应详情

A solution of 79.5 g (0.378 mol) D, 3-amino-3-(3-nitrophenyl)propionic acid, in 21 of methanol is admixed with 200 ml of sulphuric acid (conc.). The solution is heated at boiling point for 1 h. Most of the methanol is removed under reduced pressure and the residue is poured into ice-water. Using sodium carbonate, the pH is adjusted to 8. The aqueous phase is extracted with dichloromethane. Drying of the organic phase and removal of the solvent under reduced pressure gives the ester E, methyl 3-amino-3-(3-nitrophenyl)propionate, (52.8 g, 62%) as a white solid. 10 g (44.6 mmol) of E are dissolved in 20 ml of DMF. The solution is admixed with 12.3 g (88.2 mmol) of potassium carbonate, and 15.2 g (88.2 mmol) of benzyl chloroformate are added dropwise. The mixture is stirred at 23° C. for 2 h. The mixture is diluted with 200 ml of toluene and washed three times with water, and the organic phase is dried using sodium sulphate and concentrated under reduced pressure to give the colourless oil of methyl 3-benzyloxycarbonylamino-3-(3-nitrophenyl)propionate (12.6 g, 79%). MS (DCI/NH3): 376 (M+NH4)+.

1. temperatureThe solution is heated
2. customfor 1 h
3. customMost of the methanol is removed under reduced pressure
4. additionthe residue is poured into ice-water
5. extractionThe aqueous phase is extracted with dichloromethane
6. customDrying of the organic phase and removal of the solvent under reduced pressure