反应详情

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.

1. customprepared
2. customat 25° C
3. customThe precipitates were removed by filtration
4. concentrationthe filtrate concentrated under reduced pressure
5. additionThe residue was treated with ethyl acetate (1000 ml)
6. customThe precipitate formed
7. filtrationwas filtered under suction
8. washwashed with additional ethyl acetate (2×75 ml)
9. concentrationThe combined filtrate was concentrated under reduced pressure