Sulfuric Acid → Ethyl 6-bromoimidazo[1,2-a]pyridine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirring suspension of 5-bromopyridin-2-amine (1.2 g, 7.05 mmol) and ethyl 2-chloro-3-hydroxyacrylate potassium salt (6.6 g, 28.19 mmol) (prepared in a similar manner as 22) in EtOH (100 mL) at room temperature was added sulfuric acid (751 L, 14.10 mmol) dropwise. The reaction mixture was heated at 78° C. overnight. The reaction was cooled to room temperature and the solvent was concentrated. The residue was taken in water and the pH was adjusted between 6-8 with saturated sodium bicarbonate. The crude product was extracted with ethyl acetate. The organic was washed with brine and dried over anhydrous sodium sulfate. The crude product was purified by silica chromatography to yield ethyl 6-bromoimidazo[1,2-a]pyridine-3-carboxylate (24s). MS m/z 270.2 (M+1)+.

Provenance & Evidence