反应详情

(3R,5R)-5-Biphenyl-4-ylmethyl-1-(2,2-dimethylpropionyl)-3-hydroxypyrrolidin-2-one (56 g, 0.156 mol) was dissolved in EtOH (700 mL) and 12N HCl (700 mL). The mixture was heated to 90˜95° C. for 20 hours. The mixture was concentrated on an 80° C. water bath under reduced pressure. EtOH (100 mL) was added to the residue, and the resulting mixture was filtered to yield a yellow solid. This solid was suspended in 3N HCl/EtOH (800 mL). The mixture was refluxed for 3 hours. The solution was concentrated to a reduced volume (˜200 mL volume), and ether (200 mL) was added. The resulting slightly yellow solid was filtered and dried under reduced pressure to yield (2R,4R)-4-amino-5-biphenyl-4-yl-2-hydroxypentanoic acid ethyl ester (43 g).

1. temperatureThe mixture was heated to 90˜95° C. for 20 hours
2. concentrationThe mixture was concentrated on an 80° C. water bath under reduced pressure
3. additionEtOH (100 mL) was added to the residue
4. filtrationthe resulting mixture was filtered
5. customto yield a yellow solid
6. temperatureThe mixture was refluxed for 3 hours
7. concentrationThe solution was concentrated to a reduced volume (˜200 mL volume), and ether (200 mL)
8. additionwas added
9. filtrationThe resulting slightly yellow solid was filtered
10. customdried under reduced pressure