反应详情

温度

60 °C

4-Bromopyridin-2-amine (10.0 g, 0.06 mol) was mixed with ethanol (50 mL) in a reaction flask, under an atmosphere of dry nitrogen. A solution of ethyl 2-chloro-3-oxopropanoate (5% in benzene; 222 mL; Commercial solution from Toronto Research Chemicals Inc.) was added. The mixture was heated to 60° C. under nitrogen for 5 hours. After allowing the mixture to cool the solvent was removed under vacuum to give a brown solid. The solid was mixed with ethyl acetate (500 mL) and sodium bicarbonate solution (200 mL) and stirred to dissolve. The phases were separated and the bicarbonate solution was extracted further with ethyl acetate (100 mL). The combined ethyl acetate extracts were dried over sodium sulfate, filtered and concentrated under vacuum to give a solid. The crude material was dissolved in ethyl acetate and passed through a short column of silica, eluting with ethyl acetate. Fractions containing the product were concentrated under reduced pressure to give ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate (15 g) as a pale yellow solid.

1. temperatureto cool the solvent
2. customwas removed under vacuum
3. customto give a brown solid
4. dissolutionto dissolve
5. customThe phases were separated
6. extractionthe bicarbonate solution was extracted further with ethyl acetate (100 mL)
7. dry with materialThe combined ethyl acetate extracts were dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated under vacuum
10. customto give a solid
11. washeluting with ethyl acetate
12. additionFractions containing the product
13. concentrationwere concentrated under reduced pressure