Sodium Hydroxide → 1H-indole-2,5-dicarboxylic Acid

HRID 1829966Notes

Reaction equation

HRID 1829966 reaction equation
CC[O:3][C:4]([C:6]1[NH:7][C:8]2[C:13]([CH:14]=1)=[CH:12][C:11]([C:15]([OH:17])=[O:16])=[CH:10][CH:9]=2)=[O:5].[OH-].[Na+]>O.CO>[NH:7]1[C:8]2[C:13](=[CH:12][C:11]([C:15]([OH:17])=[O:16])=[CH:10][CH:9]=2)[CH:14]=[C:6]1[C:4]([OH:5])=[O:3]

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 180713652-(Ethoxycarbonyl)-1H-indole-5-carboxylic acid

Product 1

HCID 43083261H-indole-2,5-dicarboxylic AcidYield 59%

Reagents, catalysts & solvents 1

HCID 22242641Methanol--water (1/1)Solvent

Conditions

Temperature
50 °C

Procedure

A solution of 1H-indole-2,5-dicarboxylic acid 2-ethyl ester (20.0 g, 85.75 mmole) and NaOH (100 mmole) in a mixture of water/MeOH (1/1) (200 ml) was stirred at 50° C. for 4 h and then overnight at ambient temperature. The reaction mixture was evaporated in vacuo to dryness and the residue was dissolved in water (200 ml) and acidified with 1M HCl up to pH=3. The precipitates were collected on the filter and washed with water (3×50 ml) and dried over phosphorus pentoxide in dessicator to give indole-2,5-dicarboxylic acid 1 (10.38 g, 59%) of compound 1 as white crystals. MS: 203.7 (M−2H); 204.7 (M−H). 1H-NMR (DMSO-d6): δ 8.32 (m, 1H, H-4, indole); 7.80 (m, 1H, H-6, indole); 7.45 (d, 1H, H-7, indole); 7.22 (s, 1H, H-3, indole).

Workup

  1. customovernight
  2. customat ambient temperature
  3. customThe reaction mixture was evaporated in vacuo to dryness
  4. dissolutionthe residue was dissolved in water (200 ml)
  5. customThe precipitates were collected on the
  6. filtrationfilter
  7. washwashed with water (3×50 ml)
  8. dry with materialdried over phosphorus pentoxide in dessicator

Sources & evidence

ORD record
ord-95b967b647864acfb5c162fab522aecf
Source dataset
uspto-grants-2006_06
Patent number
US07064218B2

Reaction notes

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