Phenacyl bromide → 2-phenylimidazo[1,2-a]pyridine

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Reaction Steps

2-Phenylimidazo[1,2-a]pyridine was prepared by the following procedure. A solution of 2-aminopyridine (9.4 g, 0.1 mol) and bromoacetophenone (19.9 g, 0.1 mol) in ethanol (75 mL) was heated to reflux for 2 h. The ethanol was removed in vacuo and the residue redissolved in 100 mL ethyl acetate. The solution was washed with 1N NaHCO3 (50 mL), followed by a water wash. The organics were dried over magnesium sulfate, filtered and the solvent removed in vacuo. Chromatography on silica with dichloromethane/ethyl acetate (90/10) eluent yielded the 2-phenylimidazo[1,2-a]pyridine in 88% yield, mp 134° C. 1H NMR and mass spectra analysis confirmed the structure.

Provenance & Evidence