The general procedure for the synthesis of 3-bromo-5-fluorobenzoic acid from 3-bromo-5-fluorobenzonitrile was as follows: 3-bromo-5-fluorobenzonitrile (2.8 g, 13.8 mmol) was mixed with 5 M aqueous sodium hydroxide (28 mL) and heated to reflux for 2 hr. Upon completion of the reaction, the mixture was cooled to room temperature and the pH was adjusted with concentrated hydrochloric acid to 1. Subsequently, the precipitate precipitated was collected by filtration, the solid was washed with cold water and dried to give 3-bromo-5-fluorobenzoic acid (2.8 g, 94% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CD3OD): δ 6.31 (dt, J = 8.08, 2.02 Hz, 1H), 6.37-6.43 (m, 1H), 6.68 (s, 1H).
