Ethanol → 7-Methoxy-1H-indole-3-carboxylic acid

HRID 1089532Notes

Reaction equation

HRID 1089532 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[C:3]([C:10]([OH:12])=[O:11])=[CH:2]1.[CH2:13]([OH:15])C>[OH-].[Na+]>[CH3:13][O:15][C:8]1[CH:7]=[CH:6][CH:5]=[C:4]2[C:9]=1[NH:1][CH:2]=[C:3]2[C:10]([OH:12])=[O:11]

Participants

4

Reactant 2

HCID 702EthanolHCID 69867Indole-3-Carboxylic Acid

Product 1

HCID 150679677-Methoxy-1H-indole-3-carboxylic acidYield 47%

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Procedure

Preparation of 5 was based on a procedure for the synthesis of indole-3-carboxylic acid reported by R. K. Mackie et al. [supra]. To a 200-mL round bottom flask, 2.369 g of 4 (9.75 mmol) was added. Compound 4 was dissolved in 19 mL of absolute ethanol and 53 mL of 5N aqueous sodium hydroxide, refluxed overnight, and allowed to cool. The ethanol was removed by rotary evaporation, and the resulting solution was extracted with two 25-mL portions of diethyl ether. The aqueous solution was acidified with concentrated hydrochloric acid, and the peach-colored precipitate was collected. Recrystallization from hot aqueous ethanol (50:50 ethanol:water) yielded 0.883 g (47%) of 5 as cream-colored crystals: 1H NMR (acetone-d6) δ 3.95 (s, 3H, OCH3), 6.76 (d, 1H, J=7.3 Hz), 7.10 (app. t, 1H, J=8 Hz), 7.71 (d, 1H, J=8.5 Hz), 7.95 (m, 1H), 11.0 (br s, 1H).

Workup

  1. customPreparation of 5
  2. temperatureto cool
  3. customThe ethanol was removed by rotary evaporation
  4. extractionthe resulting solution was extracted with two 25-mL portions of diethyl ether
  5. customthe peach-colored precipitate was collected
  6. customRecrystallization from hot aqueous ethanol (50:50 ethanol:water)

Sources & evidence

ORD record
ord-d73dcd1092c549afa1619207c67d11a7
Source dataset
uspto-grants-1990_10
Patent number
US04966913

Reaction notes

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