Methanol → Methyl 5-oxo-L-prolinate

Participants

Reaction Steps

To a solution of (2S)-5-pyrrolidone-2-carboxylic acid (75 g) in methanol (580 ml) was added dropwise thionyl chloride (150 ml) at 0° C. After the addition, the reaction mixture was allowed to warm to room temperature and stirred for two hours. The solvent was removed in vacuo, and the residue was diluted with a mixture of ethyl acetate (1 l), methanol (50 ml) and water (10 ml). To this mixture was added by portions potassium carbonate (50 g), and the mixture was stirred for two hours. The precipitate was filtered off, and the filtrate was dried over magnesium sulfate. Evaporation of the solvent gave methyl (2S)-5-pyrrolidone-2-carboxylate (82.5 g) as an oil.

Provenance & Evidence