Water → 9-oxo-9H-pyrrolo[1,2-a]indole-5-carboxylic acid methyl ester

HRID 1925561Notes

Reaction equation

HRID 1925561 reaction equation
B(Br)(Br)Br.CO[C:7](=[O:23])[C:8]1[CH:17]=[CH:16][CH:15]=[C:10]([C:11]([O:13][CH3:14])=[O:12])[C:9]=1[N:18]1[CH:22]=[CH:21][CH:20]=[CH:19]1.O>ClCCl>[CH3:14][O:13][C:11]([C:10]1[CH:15]=[CH:16][CH:17]=[C:8]2[C:9]=1[N:18]1[CH:19]=[CH:20][CH:21]=[C:22]1[C:7]2=[O:23])=[O:12]

Participants

5

Reactant 3

HCID 962WaterHCID 25134Boron tribromideHCID 13113670Dimethyl 2-(1H-pyrrol-1-yl)benzene-1,3-dicarboxylate

Product 1

HCID 672994649-oxo-9H-pyrrolo[1,2-a]indole-5-carboxylic acid methyl esterYield 53.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

In a 50 ml round-bottomed flask, 3 ml of a 1M solution of boron tribromide in dichloromethane are added, at ambient temperature, to a mixture of 260 mg of 2-pyrrol-1-ylisophthalic acid dimethyl ester (which can be prepared according to Helvetica Chim. Acta 1983, 66(7), 2135) dissolved in 4 ml of dichloromethane. The reaction medium is stirred at ambient temperature for 2 hours and then 5 ml of water are added. After separation by settling out, the aqueous phase is re-extracted with twice 15 ml of dichloromethane. The combined organic phases are washed with twice 20 ml of water, dried over magnesium sulphate, and evaporated to dryness under vacuum. The residue is chromatographed on silica gel (15-40 μm), elution being carried out with a mixture of dichloromethane and cyclohexane (50/50 v/v). 122 mg of 9-oxo-9H-pyrrolo[1,2-a]indole-5-carboxylic acid methyl ester are obtained in the form of a yellowish solid, the characteristics of which are identical to those of the product obtained by method 1.

Workup

  1. customAfter separation
  2. extractionthe aqueous phase is re-extracted with twice 15 ml of dichloromethane
  3. washThe combined organic phases are washed with twice 20 ml of water
  4. dry with materialdried over magnesium sulphate
  5. customevaporated to dryness under vacuum
  6. customThe residue is chromatographed on silica gel (15-40 μm), elution
  7. additionbeing carried out with a mixture of dichloromethane and cyclohexane (50/50 v/v)

Sources & evidence

ORD record
ord-1f071fe7d74c42359df1c4c7e35e5759
Source dataset
uspto-grants-2012_05
Patent number
US08178687B2

Reaction notes

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