Ethanol → Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

HRID 706758Notes

Reaction equation

HRID 706758 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][N:5]=[C:4]([NH2:8])[CH:3]=1.C(O)C.Cl[CH:13]([CH:19]=O)[C:14]([O:16][CH2:17][CH3:18])=[O:15].C(=O)(O)[O-].[Na+]>C(OCC)(=O)C>[Br:1][C:2]1[CH:7]=[CH:6][N:5]2[C:13]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:19][N:8]=[C:4]2[CH:3]=1

Participants

6

Reactant 4

HCID 702EthanolHCID 118030Ethyl (chloroformyl)acetateHCID 516892Sodium BicarbonateHCID 6932822-Amino-4-bromopyridine

Product 1

HCID 67260906Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent2×

Conditions

Temperature
60 °C

Procedure

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 to give ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate as a pale yellow solid (15 g).

Workup

  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

Sources & evidence

ORD record
ord-7ac90af7acfc4f9b9f5b88228e5c185d
Source dataset
uspto-grants-2015_11
Patent number
US09174981B2

Reaction notes

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