D-Phenylalanine → (R)-2-Bromo-3-phenylpropionic acid

HRID 902905

Reaction equation

HRID 902905 reaction equation
[Br-:1].[K+].N[C@@H:4]([C:12]([OH:14])=[O:13])[CH2:5][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.N([O-])=O.[Na+]>S(=O)(=O)(O)O>[Br:1][C@H:4]([CH2:5][C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)[C:12]([OH:14])=[O:13]

Participants

5

Reactant 3

HCID 71567D-PhenylalanineHCID 253877Potassium BromideHCID 23668193Sodium Nitrite

Product 1

HCID 11746403(R)-2-Bromo-3-phenylpropionic acidYield 51.9%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
0 °C

Procedure

Potassium bromide (24.49 g, 0.21 moles) was first dissolved in a 2.50 N aqueous solution of sulfuric acid (120 mL). To this stirring solution was then added D-phenylalanine (10.00 g, 60.54 mmoles). After the addition, the mixture was cooled down to 0° C. and sodium nitrite (6.27 g., 90.87 mmoles) was added in small portions during 30 minutes. A strong bubbling was observed. The reaction was kept at this temperature for 50 minutes, and it was then allowed to proceed at room temperature for another 60 minutes. The crude product was isolated using standard work up and the obtained residue was purified by flash chromatography (SiO2, 30% ethyl acetate-70% hexanes) to give 7.20 g (51.9% yield) of the title compound as a yellowish oil: 1H NMR (CDCl3, 300 MHz) □ 10.86 (br s, 1H), 7.31 (m, 5H), 4.48 (t, 1H), 3.51 (dd, 1H), 3.29 (dd, 1H); 13C NMR (CDCl3, 75 MHz) □175.29, 136.26, 129.10, 128.69, 127.42, 44.83, 40.62.

Workup

  1. additionAfter the addition
  2. customA strong bubbling
  3. waitto proceed at room temperature for another 60 minutes
  4. customThe crude product was isolated
  5. customthe obtained residue was purified by flash chromatography (SiO2, 30% ethyl acetate-70% hexanes)

Sources & evidence

ORD record
ord-7032ca5b14e5440d92c258596283f81f
Source dataset
uspto-grants-2008_04
Patent number
US07365091B2

Linked notes

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