L-Pyroglutamic Acid → Benzyl 5-oxoprolinate

HRID 1099319Notes

Reaction equation

HRID 1099319 reaction equation
[NH:1]1[C:5](=[O:6])[CH2:4][CH2:3][C@H:2]1[C:7]([OH:9])=[O:8].C(=O)([O-])[O-].[K+].[K+].[CH2:16](Br)[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1>CN(C)C=O.C(OCC)(=O)C>[CH2:16]([O:8][C:7]([C@@H:2]1[CH2:3][CH2:4][C:5](=[O:6])[NH:1]1)=[O:9])[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1

Participants

6

Reactant 3

HCID 7405L-Pyroglutamic AcidHCID 7498Benzyl BromideHCID 11430Potassium Carbonate

Product 1

HCID 2381219Benzyl 5-oxoprolinate

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 8857Ethyl AcetateSolvent

Procedure

A solution of 387 g of L-pyro-glutamic acid in 300 mL of dimethylformamide is treated with 103.6 g of potassium carbonate at room temperature. Benzyl bromide (35.6 mL) is added and the suspension stirred room temperature for 4 hours. The suspension is filtered and the solid washed with 300 mL of acetone. The filtrate is evaporated at 50° C. to give an oil. The oil is dissolved in 300 mL of ethyl acetate and washed with 300 mL of water. The aqueous phase is re-extracted with 150 mL of ethyl acetate and the organic layers combined, dried and the solvent removed to give (S)-5-oxo-pyrrolidine-2-carboxylic acid benzyl ester as an oil.

Workup

  1. filtrationThe suspension is filtered
  2. washthe solid washed with 300 mL of acetone
  3. customThe filtrate is evaporated at 50° C.
  4. customto give an oil
  5. washwashed with 300 mL of water
  6. extractionThe aqueous phase is re-extracted with 150 mL of ethyl acetate
  7. customdried
  8. customthe solvent removed

Sources & evidence

ORD record
ord-24d489e84c7b48579ac2aa1a258272ee
Source dataset
uspto-grants-2012_03
Patent number
US08143416B2

Reaction notes

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