Water → 1-(1,3-Dioxolan-2-ylethyl)-3,5-difluorobenzene

Temperatur

0 °C

To 95.0 g (221 mmol) of dried 1,3-dioxolan-2-ylmethyl triphenylphosphonium bromide was added 800 ml of tetrahydrofuran (hereinafter abbreviated as “THF”), and the mixture was cooled to 0° C. 25.0 g (223 mmol) of potassium-t-butoxide was gradually added thereto at that temperature and the mixture was stirred for one hour. To the resulting mixture was added dropwise a solution of 25.0 g (176 mmol) of 3,5-difluorobenzaldehyde in 50 ml of THF and the mixture was stirred at 0° C. for one hour and then stirred at room temperature for 12 hours. 500 ml of water was added thereto and the reaction product was extracted with toluene. The extract was washed with brine, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by column chromatography on silica gel (eluting solvent: toluene) and the solvent was distilled off under reduced pressure. The residue thus obtained was dissolved in 600 ml of ethanol and the resultant solution was hydrogenated with 5% palladium/carbon as a catalyst and filtered to separate the catalyst. The solvent was distilled off under reduced pressure to afford 30.9 g (154 mmol) of 1-(1,3-dioxolan-2-ylethyl)-3,5-difluorobenzene. (Yield: 87.5%)

1. stirringthe mixture was stirred at 0° C. for one hour
2. stirringstirred at room temperature for 12 hours
3. extractionthe reaction product was extracted with toluene
4. washThe extract was washed with brine
5. dry with materialdried over magnesium sulfate
6. distillationthe solvent was distilled off under reduced pressure
7. customThe residue was purified by column chromatography on silica gel (eluting solvent: toluene)
8. distillationthe solvent was distilled off under reduced pressure
9. customThe residue thus obtained
10. filtrationfiltered
11. customto separate the catalyst
12. distillationThe solvent was distilled off under reduced pressure

ORD-Eintrag

ord-cb98c0af645c4cb580e522b98d8f0bf1

Quelldatensatz

uspto-grants-2003_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06599590B2