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

HRID 1872172Notes

Reaction equation

HRID 1872172 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. 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. temperatureThe mixture was cooled in an ice bath
  5. filtrationfiltered
  6. washthe resulting colorless solid washed with cold water
  7. customdried (1.51 g)
  8. temperaturecooled
  9. customgiving a solid which
  10. filtrationwas filtered
  11. washwashed with cold ethyl acetate
  12. customdried
  13. customHPLC (60/40) 3.09 minutes (97%)

Sources & evidence

ORD record
ord-64b1aaa7a84d4999bbe39e634109a876
Source dataset
uspto-grants-2000_08
Patent number
US06107329

Reaction notes

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