Sulfuric Acid → 3-Carbethoxy-5-chloromethylimidazo[1,2-a]pyridine sulfate

HRID 619539Notes

Reaction equation

HRID 619539 reaction equation
C(C1N2C(C)=CC=CC2=NC=1)(OCC)=O.ClN1C(=O)CCC1=O.FC(F)(F)C(O)=O.[C:31]([C:36]1[N:40]2[C:41]([CH2:45][Cl:46])=[CH:42][CH:43]=[CH:44][C:39]2=[N:38][CH:37]=1)([O:33][CH2:34][CH3:35])=[O:32].[S:47](=[O:51])(=[O:50])([OH:49])[OH:48]>C(OCC)(=O)C.C([O-])(O)=O.[Na+].C(#N)C>[S:47]([OH:51])([OH:50])(=[O:49])=[O:48].[C:31]([C:36]1[N:40]2[C:41]([CH2:45][Cl:46])=[CH:42][CH:43]=[CH:44][C:39]2=[N:38][CH:37]=1)([O:33][CH2:34][CH3:35])=[O:32]

Participants

9

Reactant 5

HCID 1118Sulfuric AcidHCID 6422Trifluoroacetic acidHCID 31398ChlorosuccinimideHCID 108575483-Carbethoxy-5-chloromethylimidazo[1,2-a]pyridineHCID 11816548Ethyl 5-methylimidazo[1,2-a]pyridine-3-carboxylate

Product 1

HCID 702111023-Carbethoxy-5-chloromethylimidazo[1,2-a]pyridine sulfateYield 22.4%

Reagents, catalysts & solvents 3

HCID 6342AcetonitrileSolventHCID 8857Ethyl AcetateSolventHCID 516892Sodium BicarbonateSolvent

Procedure

To a solution prepared by dissolving 43.91 g (215.03 mM) of 3-carbethoxy-5-methylimidazo[1,2-a]pyridine in 200 ml of ethyl acetate was added 31.58 g (236.53 mM) of N-chlorosuccinimide. Then, 1.66 ml (21.50 mM) of trifluoroacetic acid was added dropwise at room temperature. This mixture was stirred under argon gas at room temperature for 14 hours. After completion of the reaction, the reaction mixture was poured in 300 ml of saturated aqueous NaHCO3 solution with ice-cooling and extracted with 200 ml of ethyl acetate. The organic layer was washed with 300 ml of saturated aqueous NaCl solution and dried over MgSO4 and the solvent was distilled off under reduced pressure to recover 22.15 g of crude 3-carbethoxy-5-chloromethylimidazo[1,2-a]pyridine as tan-colored liquid. To a solution prepared by dissolving 22.15 g of this crude 3-carbethoxy-5-chloromethylimidazo[1,2-a]pyridine in 200 ml of acetonitrile was added 4.95 ml (92.80 mM) of sulfuric acid with ice-cooling and the mixture was stirred. The purified precipitate was recovered by filtration, rinsed with a small amount of acetonitrile, and dried in vacuo to provide 16.20 g (yield 22.4%) of the title compound as orchre powders.

Workup

  1. customTo a solution prepared
  2. customAfter completion of the reaction
  3. temperaturecooling
  4. extractionextracted with 200 ml of ethyl acetate
  5. washThe organic layer was washed with 300 ml of saturated aqueous NaCl solution
  6. dry with materialdried over MgSO4
  7. distillationthe solvent was distilled off under reduced pressure
  8. customto recover 22.15 g of crude 3-carbethoxy-5-chloromethylimidazo[1,2-a]pyridine as tan-colored liquid
  9. customTo a solution prepared
  10. temperaturecooling
  11. stirringthe mixture was stirred
  12. filtrationThe purified precipitate was recovered by filtration
  13. washrinsed with a small amount of acetonitrile
  14. customdried in vacuo

Sources & evidence

ORD record
ord-ee3c1e76d4974ff19826f27ec656541c
Source dataset
uspto-grants-1999_09
Patent number
US05958942

Reaction notes

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