Hydrogen Bromide → Methyl imidazo(1,2-a)pyridine-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of 1.31 parts of 2-bromo-1,1-diethoxyethane, 10 parts of water and 1.5 parts of a hydrobromic acid solution 48% in water was stirred and refluxed for 1 hours. The mixture was poured onto 50 parts of water and the whole was neutralized with potassium carbonate. Then there were added successively 5 parts of sodium hydrogen carbonate and 3 parts of methyl 2-amino-4-pyridinecarboxylate. The reaction mixture was stirred and heated for 15 minutes at 55° C. in an oil-bath. After 30 minutes, gas-evolution had ceased and the mixture was cooled. The product was extracted with dichloromethane. The extract was dried, filtered and evaporated. The residue was stirred in 2,2'-oxybispropane. The product was filtered off and dried, yielding 2.9 parts (82.3%) of methyl imidazo-[1,2-a]pyridine-7-carboxylate; mp. 143.2° C. (intermediate 13).

Provenance & Evidence