Ethanol → 3-(2-Phenylpyrazolo[1,5-a]pyridin-3-yl)-2-hydroxyiminopropionic acid

HRID 703966Notes

Reaction equation

HRID 703966 reaction equation
[C:1]1([C:7]2[C:15]([CH2:16][C:17](=S)[C:18]([OH:20])=[O:19])=[C:10]3[CH:11]=[CH:12][CH:13]=[CH:14][N:9]3[N:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.Cl.[NH2:23][OH:24].[OH-].[K+].C(O)C>O>[C:1]1([C:7]2[C:15]([CH2:16][C:17](=[N:23][OH:24])[C:18]([OH:20])=[O:19])=[C:10]3[CH:11]=[CH:12][CH:13]=[CH:14][N:9]3[N:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

6

Reactant 4

HCID 702EthanolHCID 14797Potassium HydroxideHCID 443297Hydroxyamine hydrochlorideHCID 151581733-(2-Phenylpyrazolo[1,5-a]pyridin-3-yl)-2-thioxopropionic acid

Product 1

HCID 536794283-(2-Phenylpyrazolo[1,5-a]pyridin-3-yl)-2-hydroxyiminopropionic acidYield 69.8%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)-2-thioxopropionic acid (3.74 g), hydroxylamine hydrochloride (2.63 g), 85% potassium hydroxide (2.50 g) and 80% aqueous ethanol (22.4 ml) was refluxed for 3 hours. After cooling, to the reaction mixture was added water (40 ml) and the resulting precipitates were filtered off. The filtrate was washed with methylene chloride (20 ml) twice, acidified with 10% aqueous hydrochloric acid (pH ≈2), and extracted with ethyl acetate (20 ml) twice. The organic layer was washed with water (10 ml) and a saturated aqueous solution of sodium chloride and dried over magnesium sulfate. The solvent was removed to give 3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)-2-hydroxyiminopropionic acid (2.60 g).

Workup

  1. temperaturewas refluxed for 3 hours
  2. temperatureAfter cooling, to the reaction mixture
  3. customthe resulting precipitates
  4. filtrationwere filtered off
  5. washThe filtrate was washed with methylene chloride (20 ml) twice
  6. extractionextracted with ethyl acetate (20 ml) twice
  7. washThe organic layer was washed with water (10 ml)
  8. dry with materiala saturated aqueous solution of sodium chloride and dried over magnesium sulfate
  9. customThe solvent was removed

Sources & evidence

ORD record
ord-613031f20d664acc93e4d6e0d00aebce
Source dataset
uspto-grants-1991_01
Patent number
US04985444

Reaction notes

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