Benzyl chloroformate → (2S)-2-(((benzyloxy)carbonyl)amino)-3,3-dimethylbutanoic acid

HRID 376454Notes

Reaction equation

HRID 376454 reaction equation
[NH2:1][C@H:2]([C:7]([OH:9])=[O:8])[C:3]([CH3:6])([CH3:5])[CH3:4].[OH-].[Na+].Cl[C:13]([O:15][CH2:16][C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)=[O:14]>O1CCOCC1>[C:13]([NH:1][C@H:2]([C:7]([OH:9])=[O:8])[C:3]([CH3:6])([CH3:5])[CH3:4])([O:15][CH2:16][C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)=[O:14]

Participants

5

Reactant 3

HCID 10387Benzyl chloroformateHCID 14798Sodium HydroxideHCID 164608L-tert-Leucine

Product 1

HCID 9899995(2S)-2-(((benzyloxy)carbonyl)amino)-3,3-dimethylbutanoic acidYield 200.1%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Conditions

Temperature
23 °C

Procedure

To a solution of L-tert-leucine (5.12 g, 39 mmol, 1 equiv) in 1,4-dioxane (80 mL) and 1M NaOH (39 mL, 39 mmol, 1.0 equiv) at 0° C. was added benzyl chloroformate (6.24 mL, 43.68 mmol, 1.12 equiv). The reaction mixture was stirred at 23° C. overnight, then concentrated, poured into 1M HCl (80 mL), and extracted with CH2Cl2 (2×100 mL). The organic layers were dried over Na2SO4 and concentrated to give crude CBZ-L-tert-leucine (20.7 g) as a clear oil: IR (cm-1) 3336, 1715, 1521, 1232; 1H NMR (CDCl3) δ 1.02 (s, 9H), 4.21 (d, 1H, J=9.9), 5.11 (s, 2H), 5.35 (d, 1H, J=9.0), 7.34-7.37 (m, 5H).

Workup

  1. concentrationconcentrated
  2. additionpoured into 1M HCl (80 mL)
  3. extractionextracted with CH2Cl2 (2×100 mL)
  4. dry with materialThe organic layers were dried over Na2SO4
  5. concentrationconcentrated

Sources & evidence

ORD record
ord-545f1d3f97e1420a8d90fd45d985a453
Source dataset
uspto-grants-2000_02
Patent number
US06020371

Reaction notes

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