Potassium Carbonate → Ethyl 5-methoxyimidazo[1,2-a]quinoline-2-carboxylate

HRID 616702Notes

Reaction equation

HRID 616702 reaction equation
[NH2:1][C:2]1[CH:11]=[C:10]([O:12][CH3:13])[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[N:3]=1.Br[CH2:15][C:16](=O)[C:17]([O:19][CH2:20][CH3:21])=[O:18].C(=O)([O-])[O-].[K+].[K+]>CC(C)=O>[CH3:13][O:12][C:10]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[N:3]2[CH:15]=[C:16]([C:17]([O:19][CH2:20][CH3:21])=[O:18])[N:1]=[C:2]2[CH:11]=1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 66144Ethyl bromopyruvateHCID 98556044-methoxyquinolin-2-amine

Product 1

HCID 13055756Ethyl 5-methoxyimidazo[1,2-a]quinoline-2-carboxylate

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

To 75 ml. of acetone was added 3.5 g. (0.20 mole) of 2-amino-4-methoxyquinoline, 4.3 g. (0.22 mole) of ethyl bromopyruvate and 3.0 g. (0.20 mole) potassium carbonate. The resulting mixture was heated at reflux for 5.5 hours and the resulting dark slurry allowed to stand at room temperature overnight. The solvent was removed by evaporation in vacuo and 200 ml. of water added to the residue to afford a gummy precipitate. This was extracted twice with 200 ml. portions of ethyl acetate, the extracts dried over anhydrous sodium sulfate, decolorized with active carbon (Darco), filtered and the solvent removed in vacuo to afford 3.5 g. of crude product. Filtration of the aqueous phase from the extraction step afforded another 1.0 g. of crude material. The combined crops were recrystallized from 100 ml. of 1:1 (by volume) isopropanol-water to afford 900 mg. of the title compound, M.P. 175°-176.5° C.

Workup

  1. temperatureThe resulting mixture was heated
  2. temperatureat reflux for 5.5 hours
  3. customThe solvent was removed by evaporation in vacuo and 200 ml
  4. additionof water added to the residue
  5. customto afford a gummy precipitate
  6. extractionThis was extracted twice with 200 ml
  7. dry with materialportions of ethyl acetate, the extracts dried over anhydrous sodium sulfate
  8. filtrationfiltered
  9. customthe solvent removed in vacuo
  10. customto afford 3.5 g
  11. filtrationFiltration of the aqueous phase
  12. extractionfrom the extraction step
  13. customafforded another 1.0 g
  14. customThe combined crops were recrystallized from 100 ml
  15. customof 1:1 (by volume) isopropanol-water to afford 900 mg

Sources & evidence

ORD record
ord-dce4fd4bee33490b9af22166ad63dd89
Source dataset
uspto-grants-1978_02
Patent number
US04075343

Reaction notes

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