N-methyl-2-pyrrolidone → 5-Chloro-4-fluoro-2-hydroxybenzoic acid

Participants

Reaction Conditions

Reaction Steps

1.93 g (0.01 mole) of 5-chloro-2,4-difluorobenzoic acid, 1.62 g (0.04 mole) of powdery 99% sodium hydroxide and 20 ml of 1-methyl-2-pyrrolidone were fed into a 100-ml four-necked flask provided with a thermometer, a stirrer and a reflux condenser. The mixture was stirred at 130° C. for 3 hours to give rise to a reaction. After the completion of the reaction, part of 1-methyl-2-pyrrolidone was recovered. The resulting reaction mixture was diluted with 500 ml of water and then subjected to precipitation with a 10% aqueous hydrochloric acid solution. The resulting crystals were collected by filtration, washed with water, and dried to obtain 1.76 g of 5-chloro-4-fluorosalicylic acid. The isolated yield was 92.1% relative to the 5-chloro-2,4-difluorobenzoic acid used.

Provenance & Evidence