Diethyl Ether → (4R)-4-Hydroxy-L-proline methyl ester

Participants

Reaction Steps

Acetyl chloride (7.6 ml; 107 mmol) was added slowly to MeOH (70 ml). The reaction was exothermic. (2S,4R)-4-Hydroxy-2-pyrrolidinecarboxylic acid (10 g; 76.2 mmol) was added and the mixture was refluxed for 4 hours. At this time, another portion of 3 ml of acetyl chloride in 30 ml of MeOH was added. The mixture was refluxed an additional 3 hours. The reaction was cooled to room temperature and ~750 ml of Et2O was added. The resulting colorless crystals were filtered and dried to afford 11.89 g of the title A compound.

Provenance & Evidence