Yield:-

Reaction Conditions:

in ethanol; for 3 h;Heating / reflux;

Steps:

20 Preparation 20, Ethyl imidazo[1,2-a]pyridine-2-carboxylate hydrobromide

A suspension of the compound from preparation 19 (71.9 g, 249 mmol) in ethanol (750 ml) was heated at reflux for 3 hours, then allowed to cool. The mixture was concentrated under reduced pressure, the residue triturated with ether, filtered and dried to afford the title compound as a solid, 64.17 g. ¹H-NMR (CD₃OD, 300 MHz) δ: 1.45 (t, 3H), 4.50 (q, 2H), 7.55 (m, 1H), 7.95 (m, 1H), 8.10 (dd, 1H), 8.80 (s, 1H), 8.85 (d, 1H).

References:

US2005/20611,2005,A1 Location in patent:Page/Page column 27