1,3-Dimethyl-2-imidazolidinone → 3,4-Difluoro-2-hydroxybenzoic acid

Participants

Reaction Conditions

Reaction Steps

1.76 g (0.01 mole) of 2,3,4-trifluorobenzoic acid, 1.62 g (0.04 mole) of powdery 99% sodium hydroxide and 20 ml of 1,3-dimethyl-2-imidazolidinone were fed into a 100-ml four-necked flask provided with a thermometer, a stirrer and a reflux condenser. The mixture was stirred at 150° C. for 2 hours to give rise to a reaction. After the completion of the reaction, part of 1,3-dimethyl-2-imidazolidinone 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 material was cooled in an ice bath. The resulting crystals were collected by filtration, washed with water, and dried to obtain 1.66 g of 3,4-difluorosalicylic acid. The isolated yield was 95.1% relative to the 2,3,4-trifluorobenzoic acid used.

Provenance & Evidence