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

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.

1. filtrationfiltered through a Millipore
2. filtrationfilter
3. washthe palladium was washed with 100 ml of methanol
4. concentrationThe filtrate was concentrated under vacuum to a minimal volume
5. additiontreated with 250 ml of ethyl acetate, which
6. customto form
7. filtrationThe solids were filtered
8. washwashed twice with ethyl acetate and once with hexane
9. customdried under vacuum

ORD record

ord-275a00f4136c4a85acaea719e14a257b

Source dataset

uspto-grants-1990_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04912231