Sodium Hydroxide → 4-chloro-5-fluoro-1H-indole-2-carboxylic acid

Participants

Reaction Steps

A suspension of 6.3 g of ethyl 4-chloro-5-fluoroindole-2-carboxylate in 260 ml of ethanol was treated with 130 ml of 2N sodium hydroxide solution and stirred for 3 hours. Ethanol was evaporated and the reaction solution was adjusted to pH 1 with 25% hydrochloric acid. The precipitate was washed with water and dried. There were obtained 5.3 g (96%) of crude 4-chloro-5-fluoroindole-2-carboxylic acid which was used in the next step without further purification.

Provenance & Evidence