Methanol → 1H-indole-6-carboxylic acid

HRID 1198955Notes

Reaction equation

HRID 1198955 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:10]([O:12]C)=[O:11])[CH:8]=2)[CH:3]=[CH:2]1.CO.O.O.[OH-].[Li+]>O1CCCC1>[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:10]([OH:12])=[O:11])[CH:8]=2)[CH:3]=[CH:2]1

Participants

6

Reactant 4

HCID 887MethanolHCID 962WaterHCID 168937Lithium hydroxide, monohydrateHCID 639844Methyl indole-6-carboxylate

Product 1

HCID 5952301H-indole-6-carboxylic acidYield 95%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
60 °C

Procedure

A solution of methyl indole-6-carboxylate (11.0 g) in a mixture of tetrahydrofuran (150 ml), methanol (150 ml), and water (63 ml) was treated with lithium hydroxide monohydrate (15.8 g). The mixture was stirred at 60° C. for 6 hours and then concentrated to remove the organic solvents. The residue was dissolved in water, and the solution was acidified with 50% (v/v) hydrochloric acid. The precipitate which formed was collected by filtration and dried to give indole-6-carboxylic acid (9.6 g, 95%) as a tan powder; mp 253°-254°: NMR (80 MHz; CDCl3) 6.51(m, 1H, H3 -indole), 8.04(m, 1H, H7 -indole), 11.43(broad s, 1H, NH), 12.42(broad s, 1H, OH).

Workup

  1. concentrationconcentrated
  2. customto remove the organic solvents
  3. dissolutionThe residue was dissolved in water
  4. customThe precipitate which formed
  5. filtrationwas collected by filtration
  6. customdried

Sources & evidence

ORD record
ord-66ccaebabfce4d79b3905c78d9e6c0a4
Source dataset
uspto-grants-1990_02
Patent number
US04898863

Reaction notes

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