Water → Pyrrole-2,5-dicarboxylic acid

HRID 23143Notes

Reaction equation

HRID 23143 reaction equation
[NH:1]1[C:5]([CH:6]=[O:7])=[CH:4][CH:3]=[C:2]1[CH:8]=[O:9].[O-:10][Mn](=O)(=O)=O.[K+].[OH2:16]>>[NH:1]1[C:5]([C:6]([OH:7])=[O:16])=[CH:4][CH:3]=[C:2]1[C:8]([OH:10])=[O:9]

Participants

4

Reactant 3

HCID 962Water2×HCID 516875Potassium PermanganateHCID 27249571H-pyrrole-2,5-dicarbaldehyde

Product 1

HCID 11846406Pyrrole-2,5-dicarboxylic acid

Conditions

Temperature
97.5 °C

Procedure

Pyrrole-2,5-dicarbaldehyde (0.21 g, 1.71 mmol) was dissolved in 35 ml of hot water and placed in a hot water bath (95-100° C.). A solution of KMnO4 (0.788 g, 5.13 mmol) in 10 ml of water was added dropwise in a period of 5 min. The reaction mixture was stirred at 95-100° C. for 1 h, and was then cooled to 70° C. The brown precipitates (MnO2) were filtered off and washed with water. The filtrate was acidified at 0° C. with 5 M HCl to pH 2, evaporated to dryness, and dried under high vacuum. The product was dissolved in 80 ml of anhydrous EtOH and the solution was filtered through a funnel. The filtrate was evaporated to give a brown solid (0.25 g), which was used in next reaction without further purification. ESI MS: 154.00 (M−H+). 1H NMR (DMSO-d6) δ12.68 (br. S), 12.17 (s), 6.72 (s).

Workup

  1. customplaced in a hot water bath
  2. custom(95-100° C.)
  3. temperaturewas then cooled to 70° C
  4. customThe brown precipitates (MnO2)
  5. filtrationwere filtered off
  6. washwashed with water
  7. customwas acidified at 0° C. with 5 M HCl to pH 2
  8. customevaporated to dryness
  9. customdried under high vacuum
  10. dissolutionThe product was dissolved in 80 ml of anhydrous EtOH
  11. filtrationthe solution was filtered through a funnel
  12. customThe filtrate was evaporated

Sources & evidence

ORD record
ord-2e5fa9cc2eb24917b1e0dcc27fa684c8
Source dataset
uspto-grants-2005_02
Patent number
US06849713B2

Reaction notes

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