Hydrochloric Acid → 4-Hydroxy-L-proline methyl ester hydrochloride

Participants

Reaction Steps

Anhydrous HCl was bubbled through a stirred suspension of trans-4-hydroxy-L-proline (80 g, 0.61 mol) in 500 ml anhydrous methanol until the mixture was homogeneous. The reaction was heated to reflux for five hours, and the volume of the solvent then reduced by one half. Ether (100 ml) was added, and the mixture kept in a freezer overnight. The resulting precipitate was filtered, washed with ether and dried under reduced pressure to yield 111 g of present title product (93% yield). mp 170°-172° C.

Provenance & Evidence