Chloroacetaldehyde → Imidazo(1,2-a)pyridine

Participants

Reaction Steps

A mixture of 47 g. of 2-aminopyridine, 120 g. of 45% chloroacetaldehyde solution in water and 50.4 g. of sodium bicarbonate in 400 ml. of anhydrous ethanol and 100 ml. of water is heated to reflux for 3 hrs. The reaction mixture is cooled, treated with 900 ml. of water and extracted with diethyl ether (3×700 ml.). The combined extracts are dried over sodium sulfate and concentrated to a brown oil. Distillation gives 18.8 g. of the desired intermediate as a light yellow oil, b.p. 70° C./0.02 mm.

Provenance & Evidence