Sulfuric Acid → Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of 4-bromopyridin-2-amine (10 g, 57.8 mmol) and potassium (Z)-2-chloro-1-ethoxy-3-oxoprop-1-en-1-olate (step 1) (23.4 g, 124 mmol) in ethanol (200 ml) was cooled to 5° C. Sulfuric acid (7.70 ml, 144 mmol) was added dropwise and the reaction heated to reflux at 90° C. for 3 hrs. The mixture was cooled to RT and TEA (20.03 ml, 144 mmol) was slowly added and heating continued at 90° C. for 18 hrs. After cooling to RT, the mixture was filtered and the solid was partitioned between EtOAc and aqueous 2M HCl. The aqueous layer was basified (NaOH, solid pellets) and extracted using EtOAc. The combined organic extracts were dried (MgSO4) and concentrated in vacuo to afford the title compound;

Provenance & Evidence