Sulfuric Acid → tert-butyl (2S)-2-amino-3-phenylpropanoate

HRID 2185584Notes

Reaction equation

HRID 2185584 reaction equation
OS(O)(=O)=O.[NH2:6][C@H:7]([C:15]([OH:17])=[O:16])[CH2:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.[OH-].[Na+]>O1CCOCC1>[CH3:8][C:9]([O:16][C:15](=[O:17])[C@H:7]([CH2:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[NH2:6])([CH3:14])[CH3:10]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 6140L-PhenylalanineHCID 14798Sodium Hydroxide

Product 1

HCID 6931633tert-butyl (2S)-2-amino-3-phenylpropanoateYield 118%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

98% H2SO4 (7 mL; 0.13 mol) was dripped over 20 min into dioxane (70 mL), maintaining the temperature of the solution below 20° C. After addition of L-phenylalanine (commercial product) (16.5 g; 0.10 mol), the solution was stirred over 12 h at 132 kPa under an isobutene (commercial product) atmosphere (consumed isobutene 45 g; 0.80 mol). The solution was dropped into a mixture of ice (200 g) and 10 N NaOH (30 mL, 0.30 mol) and extracted with Et2O (1 L). After washing with H2O (150 mL), the organic phase was dried over Na2SO4 and evaporated in vacuo. The residue was distilled to give L-phenylalanine 1,1-dimethylethyl ester (13 g; 0.059 mol). Yield 59%.

Workup

  1. temperaturemaintaining the temperature of the solution below 20° C
  2. custom(consumed isobutene 45 g; 0.80 mol)
  3. extractionextracted with Et2O (1 L)
  4. washAfter washing with H2O (150 mL)
  5. dry with materialthe organic phase was dried over Na2SO4
  6. customevaporated in vacuo
  7. distillationThe residue was distilled

Sources & evidence

ORD record
ord-729154fbda244e198b45801e0674a2ef
Source dataset
uspto-grants-2002_06
Patent number
US06403055B1

Reaction notes

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