Methanol → 4-Hydroxy-L-proline methyl ester hydrochloride

Participants

Reaction Steps

To a solution of hydrogen chloride-methanol prepared from acetyl chloride (19 ml, 270 mmol) and methanol (170 ml) was added L-hydroxyproline (25 g, 190 mmol), and the reaction mixture refluxed for 7 hours with stirring, cooled to room temperature. The mixture was stirred at 5° C. for 1 hour after addition of diethyl ether (340 ml). The resulting precipitate was collected by filtration, washed with a solution of diethyl ether-methanol (2:1, 50 ml), and dried under nitrogen for 4 hours to afford the title compound (30.64 g, 89% yield).

Provenance & Evidence