Reaktion #500769

Reaktionsgleichung

magnesium

bromophenetole

hydrochloric acid

trimethoxyborane

5-Bromo-2-fluorobenzaldehyde

potassium carbonate

→

5-(4-ethoxyphenyl)-2-fluorobenzaldehyde

Ausbeute 82.0%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwhich was then refluxed
2. 2
   TemperaturUnder reflux
3. 3
   Temperaturrefluxed for 2 hours
4. 4
   workup.STIRRINGstirred at room temperature for 30 minutes
5. 5
   Temperaturheated
6. 6
   Temperaturunder reflux for 5 hours
7. 7
   TemperaturAfter cooling to room temperature
8. 8
   SonstigeAfter phase separation
9. 9
   Extraktionthe water layer was extracted with 80 ml of toluene
10. 10
    Waschenwashed with two 100-ml portions of saturated brine
11. 11
    workup.ADDITIONTo the organic layer, 1.0 g of activated carbon (Shirasagi A) and tri-n-butylphosphine (0.71 ml) were added
12. 12
    workup.STIRRINGstirred at 70° C. for 20 minutes
13. 13
    FiltrationAfter filtration
14. 14
    Waschenthe residue was washed with 50 ml of toluene
15. 15
    Einengenthe filtrate was concentrated under vacuum
16. 16
    workup.ADDITIONTen milliliters of ethanol was added
17. 17
    workup.ADDITION5 ml of water was added
18. 18
    Temperaturunder reflux
19. 19
    TemperaturAfter cooling
20. 20
    workup.STIRRINGthe resultant was stirred
21. 21
    Temperaturwhile cooling in ice
22. 22
    FiltrationThe resultant was filtered under reduced pressure
23. 23
    Waschenthe residue was washed with 20 ml of ethanol containing 50% of water
24. 24
    SonstigeThe residue was dried under vacuum (40° C.)

Vorschrift

Under an argon atmosphere, magnesium (1.25 g, 51.5 mmol) was suspended in 100 ml of tetrahydrofuran, which was then refluxed. Under reflux, 50 ml of a tetrahydrofuran solution of bromophenetole (10 g, 50 mmol) was dropped and refluxed for 2 hours. After cooling to −11° C., a solution of trimethoxyborane (5.6 ml, 50 mmol) in 50 ml of tetrahydrofuran was dropped at −11 to −8° C. Stirring was conducted at −10° C. for 1 hour. At room temperature, palladium (II) acetate (64 mg, 0.285 mmol) and subsequently triphenylphosphine (299 mg, 1.14 mmol) were added and stirred at room temperature for 30 minutes. 5-Bromo-2-fluorobenzaldehyde (5.79 g, 28.5 mmol) and subsequently 30 ml of an aqueous solution of potassium carbonate (20.7 g, 150 mmol) were added at room temperature and heated under reflux for 5 hours. After cooling to room temperature, 170 ml of a 2N hydrochloric acid was dropped at 20 to 30° C. After phase separation had occurred, the water layer was extracted with 80 ml of toluene. The organic layers were combined and washed with two 100-ml portions of saturated brine. To the organic layer, 1.0 g of activated carbon (Shirasagi A) and tri-n-butylphosphine (0.71 ml) were added and stirred at 70° C. for 20 minutes. After filtration, the residue was washed with 50 ml of toluene and then the filtrate was concentrated under vacuum. Ten milliliters of ethanol was added and then 5 ml of water was added under reflux. After cooling, the resultant was stirred while cooling in ice. The resultant was filtered under reduced pressure and the residue was washed with 20 ml of ethanol containing 50% of water. The residue was dried under vacuum (40° C.) to yield 5.7 g (Yield 82%) of 5-(4-ethoxyphenyl)-2-fluorobenzaldehyde.

Quelle