Potassium Hydroxide → 4-Methoxy-1H-indole-2-carboxylic acid

HRID 406476Notes

Reaction equation

HRID 406476 reaction equation
C[O:2][C:3]([C:5]1[NH:6][C:7]2[C:12]([CH:13]=1)=[C:11]([O:14][CH3:15])[CH:10]=[CH:9][CH:8]=2)=[O:4].[OH-].[K+]>CCO>[CH3:15][O:14][C:11]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:12]=1[CH:13]=[C:5]([C:3]([OH:4])=[O:2])[NH:6]2

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 688172methyl 4-methoxy-1H-indole-2-carboxylate

Product 1

HCID 9072484-Methoxy-1H-indole-2-carboxylic acidYield 89%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of 4-methoxy-1H-indole-2-carboxylic acid methyl ester (0.448 g, 2.18 mmol) in potassium hydroxide (0.612 g, 10.9 mmol) and EtOH (111 mL) was stirred at ambient temperature for about 16 h. The reaction mixture was concentrated in vacuo and the residue portioned between water (10 mL) and Et2O (10 mL). The aqueous portion was separated and acidified by the addition of 1N aqueous HCl, then extracted with Et2O (2×10 mL). The combined organic extracts were washed with brine (10 mL), dried over MgSO4, filtered, and concentrated in vacuo to give 4-methoxy-1H-indole-2-carboxylic acid (0.371 g, 89%) as a white solid which was used in subsequent reactions without further purification. 1H NMR (d6 DMSO, 400 MHz) 12.84 (1H, s), 11.74 (1H, s), 7.15 (1H, t), 7.00-7.03 (2H, m), 6.52 (1H, d), and 3.87 (3H, s).

Workup

  1. concentrationThe reaction mixture was concentrated in vacuo
  2. customThe aqueous portion was separated
  3. additionacidified by the addition of 1N aqueous HCl
  4. extractionextracted with Et2O (2×10 mL)
  5. washThe combined organic extracts were washed with brine (10 mL)
  6. dry with materialdried over MgSO4
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-530c98d716fe4dea8e6693654344fdd1
Source dataset
uspto-grants-2014_06
Patent number
US08754107B2

Reaction notes

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