Réaction #793712

Équation de réaction

ethyl 2-chloro-3-oxopropanoate

4-Fluoropyridin-2-amine

ethanol

sodium bicarbonate

→

ethyl 7-fluoroimidazo[1,2-a]pyridine-3-carboxylate

Solvants

benzene

ethyl acetate

ethyl acetate

Conditions de réaction

Traitement

1. 1
   Températureto cool the solvent
2. 2
   Autrewas removed under vacuum
3. 3
   Autreto give a brown solid
4. 4
   workup.DISSOLUTIONto dissolve
5. 5
   AutreThe phases were separated
6. 6
   Extractionthe bicarbonate solution was extracted further with ethyl acetate (75 mL)
7. 7
   SéchageThe combined ethyl acetate extracts were dried over sodium sulfate
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated under vacuum
10. 10
    Autreto give a solid
11. 11
    Lavageeluting with ethyl acetate
12. 12
    workup.ADDITIONFactions containing the desired product
13. 13
    Concentrationwere concentrated

Mode opératoire

4-Fluoropyridin-2-amine (10.0 g, 48.0 mmol) was mixed with ethanol (40 mL) in a reaction flask, under an atmosphere of dry nitrogen. A solution of ethyl 2-chloro-3-oxopropanoate (5% in benzene, 178 mL (commercial solution from Toronto Research Chemicals Inc.) was added. The mixture was heated to 60° C. under nitrogen for 4 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 (300 mL) and sodium bicarbonate solution (75 mL) and stirred to dissolve. The phases were separated and the bicarbonate solution was extracted further with ethyl acetate (75 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. Factions containing the desired product were concentrated to give ethyl 7-fluoroimidazo[1,2-a]pyridine-3-carboxylate as a white solid (13 g).

Source