Propanal → (4R)-4-benzyl-3-[(2R,3S)-3-hydroxy-2-methylpentanoyl]-1,3-oxazolidin-2-one

Temperature

-78 °C

To a dichloromethane (120 ml) solution of (4R)-4-benzyl-3-propionyl-1,3-oxazolidin-2-one (17.22 g, 73.8 mmol), 1M dibutylboron triflate dichloromethane solution (150 ml, 150 mmol) and triethylamine (24.4 ml, 179 mmol) were added dropwise while ice cooling. Subsequently the reaction solution was cooled to −78° C. and propioaldehyde (10.5 ml, 145 mmol) was added dropwise over five minutes. After the reaction solution was stirred at the same temperature for one hour, it was stirred at 0° C. for two hours. The reaction solution was ice cooled again, followed by addition of a mixed solution of phosphate buffer (pH=7)-distilled water (1:3, 160 ml). After further cooled to −10° C., a mixed solution of methanol −30% hydrogen peroxide solution (2:1, 120 ml) was added thereto, and the mixture was stirred for one hour. After the reaction solution was concentrated under reduced pressure, it was diluted with diethyl ether and washed with a saturated sodium hydrogen carbonate aqueous solution and brine. The organic layer was dried over anhydrous sodium sulfate. After the drying agent was filtered off, the organic layer was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (Merck, commercial name Silica Gel 60, 230-400 mesh; hexane:ethyl acetate=5:1) to obtain the title compound (16.4 g) as a white solid.

1. stirringit was stirred at 0° C. for two hours
2. temperaturecooled again
3. temperatureAfter further cooled to −10° C.
4. stirringthe mixture was stirred for one hour
5. concentrationAfter the reaction solution was concentrated under reduced pressure, it
6. additionwas diluted with diethyl ether
7. washwashed with a saturated sodium hydrogen carbonate aqueous solution and brine
8. dry with materialThe organic layer was dried over anhydrous sodium sulfate
9. filtrationAfter the drying agent was filtered off
10. concentrationthe organic layer was concentrated under reduced pressure
11. customThe obtained residue was purified by silica gel column chromatography (Merck, commercial name Silica Gel 60, 230-400 mesh; hexane:ethyl acetate=5:1)

ORD record

ord-92c8e4543db841bdbc710136479322e9

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07884128B2