Chloroacetaldehyde → Imidazo(1,2-a)pyridine

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.

1. additionA mixture of 47 g
2. temperatureto reflux for 3 hrs
3. temperatureThe reaction mixture is cooled
4. additiontreated with 900 ml
5. extractionof water and extracted with diethyl ether (3 × 700 ml.)
6. dry with materialThe combined extracts are dried over sodium sulfate
7. concentrationconcentrated to a brown oil
8. distillationDistillation
9. customgives 18.8 g

ORD record

ord-5fcac5fbb29a4464916c77b60ae6e831

Source dataset

uspto-grants-1978_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04129567