Reaktion #5769

Reaktionsgleichung

bromine

4-methylphenylboronic acid

bromine

water

water

→

4-bromomethylphenylboronic acid

Ausbeute 67.5%

Lösungsmittel

methyl chloroform

methyl chloroform

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated
2. 2
   Sonstigewas collected
3. 3
   Sonstigea crystalline slurry was formed
4. 4
   Temperaturto cool
5. 5
   FiltrationThe suspended solid was collected by filtration
6. 6
   Waschenwashed with methyl chloroform (2×50 ml)
7. 7
   Sonstigedried at ambient temperature

Vorschrift

A mixture of 4-methylphenylboronic acid (27.2 g; 0.2 mole) in methyl chloroform (250 ml) was heated at reflux with azeotropic removal of water until approximately 2.5 ml of water was collected and a crystalline slurry was formed. A solution of azo(bisisobutyronitrile) (1.0 g) and bromine (32 g) in methyl chloroform (25 ml) was added to the refluxing slurry over 2-3 hours. The mixture was then refluxed until the bromine colour was discharged. The reaction mixture was allowed to cool and stirred at 10°-15° C. for 30 minutes. The suspended solid was collected by filtration, washed with methyl chloroform (2×50 ml) and dried at ambient temperature to give the anhydride of 4-bromomethylphenylboronic acid (29 g) (Compound A) as a white, crystalline solid.

Quelle