Hydrochloric Acid → 2-Methyl-1H-indole-4-carboxylic acid

HRID 11406Notes

Reaction equation

HRID 11406 reaction equation
C[O:2][C:3]([C:5]1[C:6]2[CH:7]=[C:8]([CH3:14])[NH:9][C:10]=2[CH:11]=[CH:12][CH:13]=1)=[O:4].Cl>[OH-].[Na+]>[CH3:14][C:8]1[NH:9][C:10]2[CH:11]=[CH:12][CH:13]=[C:5]([C:3]([OH:4])=[O:2])[C:6]=2[CH:7]=1

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 11769304methyl 2-methyl-1H-indole-4-carboxylate

Product 1

HCID 122807892-Methyl-1H-indole-4-carboxylic acidYield 40.2%

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Conditions

Temperature
60 °C

Procedure

To a solution of 2-methylindole-4-carboxylic acid methyl ester (4.3 g; prepared in Reference Example 9) in methanol-dioxane (10 ml+10 ml) was added 5N aqueous solution of sodium hydroxide (10 ml), and the mixture was stirred at 60° C. overnight. To the reaction solution was added 2N hydrochloric acid, and then extracted with ethyl acetate. The aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with water and a saturated aqueous solution of sodium chloride, successively, dried and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (chloroform-methanol) to give the title compound (1.6 g) having the following physical data.

Workup

  1. extractionextracted with ethyl acetate
  2. extractionThe aqueous layer was extracted with ethyl acetate
  3. washThe combined organic layer was washed with water
  4. dry with materiala saturated aqueous solution of sodium chloride, successively, dried
  5. concentrationconcentrated under reduced pressure
  6. customThe residue was purified by column chromatography on silica gel (chloroform-methanol)

Sources & evidence

ORD record
ord-e966145aa40f4b01849c2a2a0a2e9290
Source dataset
uspto-grants-2006_08
Patent number
US07098234B2

Reaction notes

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