Water → 6,11-dihydro-5H-diindolo[2,3-a:2',3'-c]carbazole-2,9,14-tricarboxylic acid

Participants

Reaction Steps

10 ml of acetonitrile were placed in a 200 ml three-mouth flask followed by dissolving 1.42 g of indole-5-carboxylic acid. On the other hand, preparation of the oxidizing agent solution was carried out by dissolving 16.2 g of anhydrous ferric chloride and 5.4 g of water in 40 ml of acetonitrile and stirring for 10 minutes. Next, after dropping in the prepared oxidizing agent solution into the aqueous indole-5-carboxylic acid solution over the course of 30 minutes, the solution was stirred for 10 hours at 60° C. The reaction solution changed from a pale yellow color to a light green color while generating a small amount of heat, and its pH was 1 or less. Following completion of the reaction, the reaction solution was aspiration filtered with a Kiriyama funnel, washed with acetonitrile and then methanol and dried to obtain 1.12 g of light green 6,11-dihydro-5H-diindolo[2,3-a:2′,3′-c]carbazole-2,9,14-tricarboxylic acid (indole-5-carboxylic acid trimer) (yield: 79%).

Provenance & Evidence