L-Pyroglutamic Acid → (S)-5-Oxopyrrolidine-2-carboxamide

Participants

Reaction Steps

To a stirred solution of L-pyroglutamic acid (II) (75 gm, 0.580 mol, commercially available) in dimethylformamide (750 ml) was added 1-hydroxy benzotriazole ammonium salt (106 gm, 0.696 mol, prepared according the literature procedure described in WO 2006100119) in one lot at 25° C. To this reaction mass, DCC was added in small portions over a period of 30 minutes at 0-5° C. The reaction mixture was allowed to warm to room temperature and stiffing continued further for 2 hours. The precipitates were removed by filtration and the filtrate concentrated under reduced pressure. The residue was treated with ethyl acetate (1000 ml) and stirred for 1 hour. The precipitate formed was filtered under suction and washed with additional ethyl acetate (2×75 ml). The combined filtrate was concentrated under reduced pressure to obtain 73 gm of (S)-5-oxopyrrolidine-2-carboxamide (III) as a white solid in 98% yield. The solid thus obtained was used without further purification in the next step.

Provenance & Evidence