Benzene → (6-Bromopyridin-3-yl)(phenyl)methanone

Participants

Reaction Conditions

Reaction Steps

6-bromopyridine-3-carboxylic acid (50 g, 0.25 mol) in thionyl chloride (4a, 130 ml, 1.76 mol) was heated at reflux for 3 hours. The mixture was then concentrated under vacuum and the residue was co-evaporated with benzene to remove the thionyl chloride. The resulting acid chloride was dissolved in benzene (120 ml, 1.33 mol) and treated with AlCl3 (82.5 g, 0.6 mol) portion wise with stirring at 5° C. After heating at reflux for 6 hours, the reaction mixture was cooled to room temperature and poured into 20% HCl (500 ml), stirred for 1 h, and layers were separated. The aqueous layer was further extracted with ethyl acetate (3×100 mL). The combined organic layer was washed with brine, 50% KOH, and water (100 mL each), dried (Na2SO4), filtered and concentrated under reduced pressure to afford the product, 4-b, (50 g, 77%). 1H NMR (CDCl3, 300 MHz,): δ 8.72 (d, J=2.4 Hz, 1H), 8.04 (dd, J1=8.4 Hz, J2=2.7 Hz, 1H), 7.74 (m, 2H), 7.61 (m, 1H), 7.48 (m, 3H).

Provenance & Evidence