L-Phenylalanine → tert-butyl (2S)-2-amino-3-phenylpropanoate

HRID 1634913Notes

Reaction equation

HRID 1634913 reaction equation
[NH2:1][C@H:2]([C:10]([OH:12])=[O:11])[CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[OH-].[Na+]>C(OC(C)(C)C)(=O)C.O>[CH3:3][C:4]([O:11][C:10](=[O:12])[C@H:2]([CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[NH2:1])([CH3:9])[CH3:5]

Participants

5

Reactant 2

HCID 6140L-PhenylalanineHCID 14798Sodium Hydroxide

Product 1

HCID 6931633tert-butyl (2S)-2-amino-3-phenylpropanoateYield 64%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 10908tert-Butyl acetateSolvent

Procedure

A solution of L-phenylalanine (62.6 g; 379 mol) in tert-butyl acetate (320 mL) cooled on an ice bath and stirred vigorously is slowly added with 70% aqueous HClO4 (35 mL, 407 mol). After stirring for 11 days at room temperature, the mixture is diluted with 100 mL of water and cooled on an ice bath. The mixture is basified with 5 N NaOH to precipitate a white solid (unreacted phenylalanine) which is filtered off. The mixture is then extracted with EtOAc (4×200 mL), the organic phases are combined and washed with water (2×200 mL) and 5% Na2CO3 (300 mL). After drying over Na2SO4 and carefully removing the solvent under vacuum, the desired compound is obtained as a colourless oil (53.53 g; 242 mol), which needs no further purifications and is stored at −18° C.

Workup

  1. stirringAfter stirring for 11 days at room temperature
  2. temperaturecooled on an ice bath
  3. customto precipitate a white solid (unreacted phenylalanine) which
  4. filtrationis filtered off
  5. extractionThe mixture is then extracted with EtOAc (4×200 mL)
  6. washwashed with water (2×200 mL) and 5% Na2CO3 (300 mL)
  7. dry with materialAfter drying over Na2SO4
  8. customcarefully removing the solvent under vacuum

Sources & evidence

ORD record
ord-00cdec0fb82248bfbacf054bb364d657
Source dataset
uspto-grants-2003_01
Patent number
US06509324B1

Reaction notes

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