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

Temperature

55 °C

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 hour. 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).

1. temperaturerefluxed for 1 hour
2. stirringThe reaction mixture was stirred
3. temperaturethe mixture was cooled
4. extractionThe product was extracted with dichloromethane
5. customThe extract was dried
6. filtrationfiltered
7. customevaporated
8. stirringThe residue was stirred in 2,2'-oxybispropane
9. filtrationThe product was filtered off
10. customdried

ORD record

ord-234ad76b3c944165a16c31c76ae8e0b6

Source dataset

uspto-grants-1990_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04962115