Lithium Hydroxide → 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylic acid

Participants

Reaction Steps

The ethyl 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylate (6.4 g, 29.3 mmol) was dissolved in 75 mL of ethanol (95%), 1 M LiOH (60 mL, 60 mmol) was added and reaction was heated to reflux for 36 hours. The resulting solution was concentrated to dryness and then made acidic (pH˜2-3) with the addition of 4 N HCl; resulting solids were collected by filtration and rigorously dried to give 4.6 grams (82%) of 2,7-dimethylimidazo[1,2-a]pyridine-3-carboxylic acid, an off-white solid. mp 180-183° C.; 1H NMR (300 MHz, CD3OD) δ 9.52 (d, J=7.1 Hz, 1H), 7.73 (td, J=1.8, 0.9, 0.9 Hz, 1H), 7.48 (dd, J=7.1, 1.3 Hz, 1H), 2.81 (s, 3H), 2.63 (s, 3H). HRMS (EI), M+1 calcd. for C10H11N2O2, 191.0815; found 191.0837. Retention time=0.6-0.7 minutes (mobile phase: 60% water:acetonitrile).

Provenance & Evidence