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

Participants

Reaction Steps

Into a 1 liter Parr hydrogenation bottle was placed 29.90 g (107.12 mmol) of (cis)-1-benzyloxycarbonyl-4-hydroxy-L-proline, methyl ester (reference: J. Am. Chem. Soc., 79, 185, (1957)), 400 ml of methanol, 9.83 ml (117.90 mmol) of concentrated HCl, and 3.00 g of 10% palladium on activated carbon. The mixture was shaken under a hydrogen atmosphere at 50 psi for 4 hours, then filtered through a Millipore filter; the palladium was washed with 100 ml of methanol. The filtrate was concentrated under vacuum to a minimal volume, then treated with 250 ml of ethyl acetate, which caused a white precipitate to form. The solids were filtered, washed twice with ethyl acetate and once with hexane, and dried under vacuum to yield 20.05 g (93.1%) of the title compound.

Provenance & Evidence