Hydrochloric Acid → 5-cyano-1H-indole-2-carboxylic Acid

HRID 1760943Notes

Reaction equation

HRID 1760943 reaction equation
C([O:3][C:4]([C:6]1[NH:7][C:8]2[C:13]([CH:14]=1)=[CH:12][C:11]([C:15]#[N:16])=[CH:10][CH:9]=2)=[O:5])C.C(O)C.[OH-].[K+].Cl>O>[C:15]([C:11]1[CH:12]=[C:13]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6]([C:4]([OH:5])=[O:3])=[CH:14]2)#[N:16]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 702EthanolHCID 14797Potassium HydroxideHCID 4714953Ethyl 5-cyanoindole-2-carboxylate

Product 1

HCID 71446255-cyano-1H-indole-2-carboxylic Acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

5-Cyano-1H-indole-2-carboxylic acid ethyl ester (1.71 g, 8.0 mmol) was added to a solution of ethanol (10 mL) and potassium hydroxide (2 g) and the resulting mixture heated at reflux for 1 hour. Water was added to dissolve the precipitate, and 6N HCl was added to bring the pH to 1. A precipitate formed. The mixture was cooled in an ice bath, filtered, and the resulting colorless solid washed with cold water and dried (1.51 g). A portion (1.4 g) was suspended in hot acetic acid (40 mL) and cooled giving a solid which was filtered, washed with cold ethyl acetate and dried: Yield 980 mg 70%; HPLC (60/40) 3.09 minutes (97%).

Workup

  1. temperaturethe resulting mixture heated
  2. temperatureat reflux for 1 hour
  3. additionwas added
  4. customA precipitate formed
  5. temperatureThe mixture was cooled in an ice bath
  6. filtrationfiltered
  7. washthe resulting colorless solid washed with cold water
  8. customdried (1.51 g)
  9. temperaturecooled
  10. customgiving a solid which
  11. filtrationwas filtered
  12. washwashed with cold ethyl acetate
  13. customdried
  14. customHPLC (60/40) 3.09 minutes (97%)

Sources & evidence

ORD record
ord-fb264f3e34a64c54b63551ac6b702734
Source dataset
uspto-grants-2005_01
Patent number
US06846820B2

Reaction notes

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