Citric Acid → 6-Carbamoylimidazo[1,2-a]pyridine-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a stirring solution of ethyl 6-cyanoimidazo[1,2-a]pyridine-3-carboxylate (24q) (500 mg, 2.32 mmol) in THF:MeOH (4:1, 5 mL) was added 2N LiOH (4 mL). The reaction was heated at 60° C. for 2 h then acidified with 10% citric acid. The solvent was partially concentrated and the resulting solid was collected by vacuum filtration and was washed with excess water. The product was purified from the crude solid to afford 6-carbamoylimidazo[1,2-a]pyridine-3-carboxylic acid (110). 1H NMR (400 MHz, d6-DMSO) δ 9.80 (s, 1H), 8.33-8.31 (m, 1H), 8.29 (s, 1H), 7.95 (dd, J=2.0, 9.6 Hz, 1H), 7.83 (dd, J=0.8, 9.2 Hz, 1H), 7.69 (s, 1H). MS m/z 205.05 (M+1)+.

Provenance & Evidence