2-Oxobutanoic Acid → Ethyl 5-methoxy-3-methyl-1H-indole-2-carboxylate

HRID 1582636Notes

Reaction equation

HRID 1582636 reaction equation
S(=O)(=O)(O)O.Cl.[CH3:7][O:8][C:9]1[CH:14]=[CH:13][C:12]([NH:15]N)=[CH:11][CH:10]=1.O=[C:18]([CH2:22][CH3:23])[C:19]([OH:21])=[O:20].[CH2:24](O)[CH3:25]>>[CH3:7][O:8][C:9]1[CH:14]=[C:13]2[C:12](=[CH:11][CH:10]=1)[NH:15][C:18]([C:19]([O:21][CH2:24][CH3:25])=[O:20])=[C:22]2[CH3:23]

Participants

5

Reactant 4

HCID 582-Oxobutanoic AcidHCID 702EthanolHCID 1118Sulfuric AcidHCID 27239044-Methoxyphenylhydrazine hydrochloride

Product 1

HCID 604590Ethyl 5-methoxy-3-methyl-1H-indole-2-carboxylateYield 59%

Procedure

Concentrated sulphuric acid (1 ml) was added to a solution of 4-methoxyphenyl hydrazine hydrochloride (11.2 g) and 2-oxobutyric acid (8.72 g) in ethanol (250 ml), and the solution heated at reflux for 16 hours. The reaction was cooled, concentrated in vacuo, and the residue triturated with ethanol to give the title compound as a white solid (8.8 g, 59%). NMR δ 1.36 (t, 3H), 3.76 (s, 3H), 4.30 (q, 2H), 6.88 (dd, 1H), 7.03 (d, 1H), 7.28 (d, 1H), 11.28 (bs, 1H); m/z 232 (M−H+).

Workup

  1. temperaturethe solution heated
  2. temperatureat reflux for 16 hours
  3. temperatureThe reaction was cooled
  4. concentrationconcentrated in vacuo
  5. customthe residue triturated with ethanol

Sources & evidence

ORD record
ord-1fdcfe1f797c4084ace0cd355d1ea2f3
Source dataset
uspto-grants-2004_05
Patent number
US06737435B1

Reaction notes

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