L-Pyroglutamic Acid → tert-Butyl 5-oxo-L-prolinate

Participants

Reaction Steps

To a suspension of L-pyroglutamic acid (2.00 g, 15.49 mmol) in t-butyl acetate was added 70% HClO4 (0.46 mL, 17.04 mmol). The suspension was stirred at rt in a tightly closed flask overnight. The resulting solution was poured slowly into a sat. solution of NaHCO3 and extracted twice with EtOAc. The organic phase was dried over MgSO4 and concentrated to provide (S)-pyrrolidin-2-one-5-carboxylic acid t-butyl ester. (2.04 g, 85%) as a white solid 1H NMR (CDCl3) δ 1.48 (s, 9H), 2.16-2.48 (m, 4H), 4.14 (m, 1H), 5.97 (bs, 1H). MS calcd for C9H15NO3 +H 186, found 186.

Provenance & Evidence