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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence