L-Pyroglutamic Acid → Benzyl 5-oxoprolinate

Participants

Reaction Steps

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.

Provenance & Evidence