L-Pyroglutamic Acid → 1-(Phenylmethyl) (2S)-5-oxo-1,2-pyrrolidinedicarboxylate

HRID 1636220Notes

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.[Na+].[Na+].Cl[C:17]([O:19][CH2:20][C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1)=[O:18]>[OH-].[Na+].O1CCOCC1>[CH2:20]([O:19][C:17]([N:1]1[C:5](=[O:6])[CH2:4][CH2:3][C@H:2]1[C:7]([OH:9])=[O:8])=[O:18])[C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1

Participants

Conditions

Temperature: 0 °C

Procedure

L-Pyroglutamic acid (2.02 g, 13.83 mmol) was dissolved in 1 N NaOH (13.84 mL) and the solution was cooled to 0° C. After 30 min stirring, Na2CO3 (3.63 g) and benzyl chloroformate (4.82 mL) in dioxane (21.23 mL) were gradually added in equal portions. Stirring was continued at 0° C. for 1 h, then the solution was stirred overnight at room temperature and extracted with ethyl ether (2×20 mL). The aqueous solution was acidified with 2N HCl to pH 5 and extracted with ethyl acetate (3×50 mL). The ethyl acetate layer was dried over sodium sulfate and evaporated to give an oil, which crystallized overnight. Recrystallization of the crude product gave white crystalline material (2.86 g, 87%): FABMS 240.1 (M+H): HRFABMS Calcd for C13H14NO5 (M+H) 264.0872, Found 264.0866; Calcd for C13H13NaNO5 (M+Na) 286.0691, Found 286.0694.

Workup

stirringStirring
waitwas continued at 0° C. for 1 h
stirringthe solution was stirred overnight at room temperature
extractionextracted with ethyl ether (2×20 mL)
extractionextracted with ethyl acetate (3×50 mL)
dry with materialThe ethyl acetate layer was dried over sodium sulfate
customevaporated
customto give an oil, which
customcrystallized overnight
customRecrystallization of the crude product

Sources & evidence

ORD record: ord-091e1f1ca03e4395b85d5687637d09b9
Source dataset: uspto-grants-2000_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06034058

Reaction notes

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