Benzyl Bromide → Boc-Ala-Ala-OBzl

HRID 26328

Reaction equation

HRID 26328 reaction equation
[NH:1]([C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[C@H:2]([C:4]([NH:6][C@H:7]([C:9]([OH:11])=[O:10])[CH3:8])=[O:5])[CH3:3].C([O-])([O-])=O.[Cs+].[Cs+].[CH2:25](Br)[C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1>CO.O.CN(C=O)C>[NH:1]([C:12]([O:14][C:15]([CH3:16])([CH3:18])[CH3:17])=[O:13])[C@H:2]([C:4]([NH:6][C@H:7]([C:9]([O:11][CH2:25][C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1)=[O:10])[CH3:8])=[O:5])[CH3:3]

Participants

7

Reactant 3

HCID 7498Benzyl BromideHCID 10796Cesium carbonateHCID 6992569N-((1,1-Dimethylethoxy)carbonyl)-L-alanyl-L-alanine

Product 1

HCID 10904242Boc-Ala-Ala-OBzl

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolventHCID 6228DimethylformamideSolvent

Procedure

Boc-Ala-Ala-OH (7.23 g, 27.8 mmol) was dissolved in a mixture of 200 ml MeOH and 20 ml H2O.Cs2CO3 solution (20% aqueous) was added until the pH reached 7.0 (~30 ml) and the resultant neutral solution evaporated to dryness. The residue was re-evaporated twice with DMF (150 ml) and the gelatenous solid that remained was stirred in 120 ml DMF with benzyl bromide (7.2 g, 42 mmol) for 15 hours. The solvent was then removed by evaporation and the residue treated with 500 ml water. The product precipitated as an oil which gradually solidified on standing. It was taken up in EtOAc (400 ml), washed with H2O (3 times), dried (Na2SO4), and evaporated to a syrup which on treatment with petroleum ether began to crystallize. The product was recrystallized from EtOAc and petroleum ether to yield, 7.2 g (73.8%); mp 71°-73° (lit. mp 73°-74°; D. A. Laufer et al., J. Amer. Chem. Soc., 90, 2696 (1968)).

Workup

  1. customthe resultant neutral solution evaporated to dryness
  2. customThe residue was re-evaporated twice with DMF (150 ml)
  3. customThe solvent was then removed by evaporation
  4. additionthe residue treated with 500 ml water
  5. customThe product precipitated as an oil which
  6. washwashed with H2O (3 times)
  7. dry with materialdried (Na2SO4)
  8. customevaporated to a syrup which on treatment with petroleum ether
  9. customto crystallize
  10. customThe product was recrystallized from EtOAc and petroleum ether
  11. customto yield

Sources & evidence

ORD record
ord-81d95717c968480c8febb41b4c95e2df
Source dataset
uspto-grants-1979_04
Patent number
US04148788

Linked notes

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