Sulfuric Acid → HCID 353964, compound

HRID 2235805Notes

Reaction equation

HRID 2235805 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[CH:10]=[N:9][N:8]2[CH:11]=[CH:12][NH:13][C:7]=12)=[O:5])[CH3:2].S(=O)(=O)(O)O>C(O)C>[CH2:1]([O:3][C:4]([C:6]1[CH:10]=[N:9][N:8]([CH2:11][CH:12]([O:5][CH2:4][CH3:6])[O:3][CH2:1][CH3:2])[C:7]=1[NH2:13])=[O:5])[CH3:2]

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 178469956HCID 178469956, compound

Product 1

HCID 353964HCID 353964, compound

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Synthesis of 1H-Imidazo[1,2-b]pyrazole-7-carboxylic acid ethyl ester, K-8. To a solution of crude K-7 (2 g) in absolute ethanol (10 mL) was added aqueous 20% sulfuric acid solution (12 mL) and the resulting mixture was refluxed for 1 h. The cooled reaction mixture was concentrated to remove the solvent and the mixture was poured to ice and adjusted to pH 8 with sodium bicarbonate. The insoluble material was filtered off and filtrate was extracted with methylene chloride (2×60 mL). The combined organic extracts were dried (MgSO4), filtered and concentrated to give 1.2 g of a dark brown residue. This residue was purified by column chromatography using CH2Cl2 to 2% MeOH/CH2Cl2 to afford 280 mg of product K-8. 1H NMR.

Workup

  1. temperaturethe resulting mixture was refluxed for 1 h
  2. customThe cooled reaction mixture
  3. concentrationwas concentrated
  4. customto remove the solvent
  5. additionthe mixture was poured to ice
  6. filtrationThe insoluble material was filtered off
  7. extractionfiltrate was extracted with methylene chloride (2×60 mL)
  8. dry with materialThe combined organic extracts were dried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-0d98d4a81f2a483eb41382ba597852ae
Source dataset
uspto-grants-2010_05
Patent number
US07714017B2

Reaction notes

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