Hydrochloric Acid → 3-Cyano-4-fluorobenzoic acid

Participants

Reaction Steps

To a stirred solution of 15.0 g (97.6 mmol) 2-fluoro-5-formyl-benzonitrile (Aldrich), 150 ml dest. water and 630 ml t-butanol were added 40.8 g (361 mmol) sodium chlorite and 35.9 g (230 mmol) sodium hydrogen phosphate dihydrate. The reaction mixture was stirred over night and poured into a diluted aqueous hydrogen chloride solution (pH=3.5). The pH value was readjusted to pH=3.5 by aqueous hydrogen chloride. The aqueous solution was extracted trice with dichloromethane/isopropanol (10:1). The combined organic phases were dried (sodium sulphate) and concentrated. The residue was purified by extraction with sodium hydrogen carbonate solution and dichloromethane, acidification with aqueous solution and subsequent filtering. The solid crude product 2a was obtained in 90% yield (14.5 g, 87.8 mmol) and was used for the next step without purification.

Provenance & Evidence