Water → 5-Chloro-1H-indole-3-carboxylic acid

Participants

Reaction Steps

A solution of 5.0 g (33.0 mmol) of commercially available 5-chloro-1H-indole in 50 ml dry DMF was kept at 0° C., while 7.35 g (35.0 mmol) trifluoroacetanhydride was added dropwise. After 3 h stirring at room temperature the mixture was poured into 200 ml water, and the precipitate was filtered with suction and heated with reflux overnight in 200 ml 20% NaOH. It was extracted twice with dichloromethane, and the aqueous layer was acidified with hydrochloric acid. The crystalline title compound was collected by filtration and dried in vacuo.

Provenance & Evidence