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

Temperatur

22.5 °C

To a suspension of trans-4-hydroxy-L-proline (100 g, 0.76 mol, 1 equivalent) in methanol (850 mL), thionyl chloride (110 mL, 1.53 mol, 2 equivalents) was added drop-wise at 0-5° C. Then the reaction mixture was stirred for 4 hours at 20-25° C. The reaction mixture was concentrated under reduced pressure. The crude material was stirred in a mixture of ethanol-methyl tert-butyl ether (1:4, 500 mL) for 30 minutes and the solid was collected by filtration. The wet cake was dried in a vacuum tray dryer for 8 hours at about 50° C. to afford the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 2.09-2.24 (m, 2H), 3.07 (d, 1H, J=12.3 Hz), 3.35 (dd, 2H, J=4.2 Hz, J=11.7 Hz), 3.76 (s, 3H), 4.42-4.51 (m, 2H), 5.59 (bs, 1H), 9.3 (bs, 1H), 10.3 (bs, 1H).

1. additionwas added drop-wise at 0-5° C
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. stirringThe crude material was stirred in a mixture of ethanol-methyl tert-butyl ether (1:4, 500 mL) for 30 minutes
4. filtrationthe solid was collected by filtration
5. customThe wet cake was dried in a vacuum tray dryer for 8 hours at about 50° C.

ORD-Eintrag

ord-773e00bff8a44a90980ea696f862de4b

Quelldatensatz

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08648074B2