Methanol → (4R)-4-Hydroxy-L-proline methyl ester

Participants

Reaction Conditions

Reaction Steps

Thionyl chloride (270 mL) was added dropwise to methanol (1500 mL) over 1 hour, followed by the addition of (4R)-4-hydroxy-L-proline (150 g). The mixture was stirred at reflux for 36 hours, and then concentrated under reduced pressure. Methanol (1500 mL) was added, followed by a slow addition of triethylamine (310 mL). The mixture was cooled to 0° C., filtered, and the filtrate was concentrated to afford methyl (4R)-4-hydroxy-L-prolinate. The residue was used directly without further purification.

Provenance & Evidence