Methanol → methyl 6-hydroxy-1H-indole-2-carboxylate

HRID 230562Notes

Reaction equation

HRID 230562 reaction equation
S(=O)(=O)(O)O.[OH:6][C:7]1[CH:15]=[C:14]2[C:10]([CH:11]=[C:12]([C:16]([OH:18])=[O:17])[NH:13]2)=[CH:9][CH:8]=1.[OH-].[K+].[CH3:21]O>O>[OH:6][C:7]1[CH:15]=[C:14]2[C:10]([CH:11]=[C:12]([C:16]([O:18][CH3:21])=[O:17])[NH:13]2)=[CH:9][CH:8]=1

Participants

6

Reactant 4

HCID 887MethanolHCID 1118Sulfuric AcidHCID 14797Potassium HydroxideHCID 223501916-Hydroxy-1H-indole-2-carboxylic acid

Product 1

HCID 10535709methyl 6-hydroxy-1H-indole-2-carboxylate

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

0.144 ml (2.70 mmol) of concentrated sulfuric acid is added, at ambient temperature, to a solution of 5.98 g (33.75 mmol) of 6-hydroxy-1H-indole-2-carboxylic acid in 350 ml of methanol. The mixture is refluxed for 9 days and the reaction mixture is then concentrated to dryness under reduced pressure. The residue obtained is taken up in water and alkalinized to pH9 with a 38% potassium hydroxide solution, and the product is then extracted 6 times with ethyl acetate. The organic phases are combined and then dried over anhydrous magnesium sulfate, filtered, and concentrated to dryness under reduced pressure, to give 5.81 g of methyl 6-hydroxy-1H-indole-2-carboxylate in the form of a brown solid.

Workup

  1. temperatureThe mixture is refluxed for 9 days
  2. concentrationthe reaction mixture is then concentrated to dryness under reduced pressure
  3. customThe residue obtained
  4. extractionthe product is then extracted 6 times with ethyl acetate
  5. dry with materialdried over anhydrous magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated to dryness under reduced pressure

Sources & evidence

ORD record
ord-246562f09ddb427cac920a069b8b2a11
Source dataset
uspto-grants-2009_07
Patent number
US07566736B2

Reaction notes

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