Toluene → (S)-4-(2-Hydroxy-2-methylpropyl)oxazolidin-2-one

Methylmagnesium bromide (227 mL of 3M solution in diethyl ether) was added to a mixture of toluene (340 mL) and THF (340 mL) at −20° C. A warm THF solution (170 mL) of the ester from Step 2 (40 g) was then added dropwise maintaining the temperature below −10° C. The mixture was aged for 2 hours and was then slowly added to a mixture of water (1000 mL) and acetic acid (200 mL) and the resultant mixture was stirred for 2 hours at room temperature. The aqueous layer was separated and the organic layer was extracted with water (2×200 mL). The product was extracted from the combined aqueous layers using dichloromethane and a continuous extractor. The dichloromethane extract was evaporated to dryness using heptane as a co-solvent to azeotrope off the acetic acid. The residue was purified by chromatography on SiO2 using ethanol and dichloromethane (1:30) to yield (4S)-4-(2-hydroxy-2-methylpropyl)-1,3-oxazolidin-2-one.

1. temperaturemaintaining the temperature below −10° C
2. customThe aqueous layer was separated
3. extractionthe organic layer was extracted with water (2×200 mL)
4. extractionThe product was extracted from the combined aqueous layers
5. extractionThe dichloromethane extract
6. customwas evaporated to dryness
7. customThe residue was purified by chromatography on SiO2

ORD-Eintrag

ord-78236a396efb4c038f4b2f43f02560a6

Quelldatensatz

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07973037B2