Reaktion #565439

Reaktionsgleichung

1,3-dibromobenzene

pyridine-3-boronic acid-1,3-propanediol cyclic ester

Na2CO3

→

3-(3-bromophenyl)pyridine

Ausbeute 64.0%

Lösungsmittel

EtOH

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas degassed with a stream of N2 for 10 min
2. 2
   Temperaturthe reaction heated
3. 3
   Temperaturat reflux for 14 h
4. 4
   EinengenThe mixture was concentrated under reduced pressure
5. 5
   Sonstigeto remove the organic solvents
6. 6
   ExtraktionThe organics were extracted with EtOAc (2×125 ml)
7. 7
   Waschenwashed with brine (75 ml)
8. 8
   Trocknendried (MgSO4)
9. 9
   Einengenconcentrated under reduced pressure
10. 10
    SonstigeThe resulting crude residue was purified by column chromatography on silica

Vorschrift

A mixture of 1,3-dibromobenzene (8.7 g, 36.8 mmol) and pyridine-3-boronic acid-1,3-propanediol cyclic ester (4.0 g, 24.5 mmol) in EtOH (60 ml) and toluene (60 ml) together with 2N Na2CO3 solution (24.5 ml) was degassed with a stream of N2 for 10 min. Tetrakis(triphenylphosphine)-palladium(0) (0.25 g, 0.22 mmol) was added and the reaction heated at reflux for 14 h. The mixture was concentrated under reduced pressure to remove the organic solvents. The organics were extracted with EtOAc (2×125 ml) and then washed with brine (75 ml), dried (MgSO4), and concentrated under reduced pressure. The resulting crude residue was purified by column chromatography on silica, using 80% diethyl ether in hexane as the eluent, to yield 3-(3-bromophenyl)pyridine (3.66 g, 64%): δH (360 MHz, CDCl3) 7.30-7.42 (2H, m), 7.47-7.60 (2H, m), 7.72 (1H, s), 7.84 (1H, dt, J 8 and 2), 8.62 (1H, dd, J 4.8 and 1.5), 8.83 (1H, s).

Quelle