Water → Pyrrole-2,5-dicarboxylic acid

Participants

Reaction Conditions

Reaction Steps

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) δ 12.68 (br. S), 12.17 (s), 6.72 (s).

Provenance & Evidence