Reaktion #500025

Reaktionsgleichung

triethylborate

p-bromoanisole

magnesium

sulphuric acid

→

expected product

(4-Methoxyphenyl)-boronic Acid

Lösungsmittel

ether

diethyl ether

diethyl ether

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITthe mixture is left
2. 2
   Temperaturunder reflux for 2 hours
3. 3
   workup.WAITfor 1 hour at ambient temperature
4. 4
   workup.WAITfollowed by agitation for 1 hour
5. 5
   ExtraktionThe organic phase is extracted with 100 ml of an aqueous solution saturated in sodium bicarbonate
6. 6
   Extraktionextracted with ether
7. 7
   Sonstigedried
8. 8
   Sonstigeevaporated under reduced pressure

Vorschrift

100 ml of a solution of 10 g of p-bromoanisole in anhydrous diethyl ether is added dropwise under reflux to a suspension, under inert gas, of 1.3 g of magnesium turnings in 5 ml of anhydrous diethyl ether, and the mixture is left under reflux for 2 hours. The reaction medium is then poured into a solution of 9.02 ml of triethylborate in 60 ml of anhydrous ether cooled down to −70° C. After agitation for 1 hour at −70° C., then for 1 hour at ambient temperature, the solution is poured into a mixture comprising 11 ml of sulphuric acid and 50 g of ice and water followed by agitation for 1 hour. The organic phase is extracted with 100 ml of an aqueous solution saturated in sodium bicarbonate, the aqueous phases are combined, then reacidified with 6N hydrochloric acid, extracted with ether, dried and evaporated under reduced pressure. 3.9 g of expected product is obtained.

Quelle