3-Bromopyridine → 2-Methoxy-6-(3-pyridyl)quinoline

Participants

Reaction Steps

t-Butyl lithium (7.7 cm3 of a 2.6M solution in pentane) was added dropwise over 5 minutes to a stirred solution of 3-bromopyridine (1.44 cm3) in THF (25 cm3) at -100° under nitrogen. After stirring for 10 minutes a solution of anhydrous zinc chloride (2.05 g) in THF (20 cm3) was added slowly and the mixture was allowed to warm to room temperature over 1 hour. A solution of 2-methoxy-6-bromoquinoline (2.38 g) and tetrakis-(triphenylphosphine)palladium(O) (0.08 g) in THF (10 cm3) was added and the mixture was heated under reflux for 9 hours. Ammonium chloride solution (20 cm3) was then added, the mixture was concentrated in vacuo, and the aqueous phase extracted with chloroform (3×50 cm3). The dried (MgSO4) extracts were evaporated in vacuo to give a solid which was chromatographed on silica (Merck "MK. 60.9385") eluting with ethyl acetate:hexane, 1:1, to afford a residue which was recrystallised from petroleum ether (b.p. 60°-80°)-ether to afford 2-methoxy-6-(3-pyridyl)quinoline, m.p. 89°-91°, (0.35 g).

Provenance & Evidence