Methanol → 2(R)-(4-methoxy-2,3,6-trimethylbenzenesulfonylamino)-3(S)-hydroxybutyric acid

Temperatur

80 °C

To a suspension of D-threonine (7.87 g, 66.1 mmol) in acetonitrile (100 mL) was added trimethylsilyl cyanide (40 mL, 298 mmol) and the resulting solution was heated to 80° C. After 1 h, 4-methoxy-2,3,6-trimethylbenzenesulfonyl chloride (17.3 g, 69.4 mmol) was added and the heating was continued. After 12 h, the reaction mixture was cooled to room temperature. Methanol (15 mL) was added, and the organics were removed in vacuo. The residue was diluted with diethyl ether (300 mL) and after cooling the reaction mixture to 0° C., the pH was adjusted to 8 with 6 N aqueous sodium hydroxide solution. The organic layer was collected and the aqueous layer was extracted with diethyl ether. The aqueous layer was adjusted to pH 4 and again extracted with ethyl acetate. The combined organic extracts were dried over magnesium sulfate and concentrated to afford 2(R)-(4-methoxy-2,3,6-trimethylbenzenesulfonylamino)-3(S)-hydroxybutyric acid (22 g) as a brown foam which was used without further purification.

1. waitAfter 12 h
2. temperaturethe reaction mixture was cooled to room temperature
3. customthe organics were removed in vacuo
4. additionThe residue was diluted with diethyl ether (300 mL)
5. temperatureafter cooling the reaction mixture to 0° C.
6. customThe organic layer was collected
7. extractionthe aqueous layer was extracted with diethyl ether
8. extractionagain extracted with ethyl acetate
9. dry with materialThe combined organic extracts were dried over magnesium sulfate
10. concentrationconcentrated

ORD-Eintrag

ord-680ec878cfe041fd960267ac0c4bfef4

Quelldatensatz

uspto-grants-2002_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06492394B1