Methanol → (2R,4R)-methyl 4-hydroxypyrrolidine-2-carboxylate

Temperature

0 °C

Cis-4-Hydroxy-D-proline (15 g, 115 mmol) was suspended in 150 mL anhydrous methanol under an argon atmosphere, then cooled to 0° C. before bubbling in HCl gas for 15 minutes. The solution gradually became homogenous. The argon and HCl gas lines were removed and the solution was refluxed for 4 h. The solution was cooled and then concentrated under reduced pressure. The crude material was redissolved in 100 mL methanol and diethyl ether was added until a precipitate formed. The precipitate was filtered off, washed with diethyl ether, and dried in vacuo overnight to give 1 (20 g, 95%) as a white solid. MS: APCI (AP+): 146 (M)+.

1. custombefore bubbling in HCl gas for 15 minutes
2. customThe argon and HCl gas lines were removed
3. temperaturethe solution was refluxed for 4 h
4. temperatureThe solution was cooled
5. concentrationconcentrated under reduced pressure
6. dissolutionThe crude material was redissolved in 100 mL methanol
7. additiondiethyl ether was added until a precipitate
8. customformed
9. filtrationThe precipitate was filtered off
10. washwashed with diethyl ether
11. customdried in vacuo overnight

ORD record

ord-6155d8f7bace48c5a8305ca6c5344241

Source dataset

uspto-grants-2008_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07407972B2