Synthesis
The general procedure for the synthesis of 3-fluoro-5-methoxybenzoic acid from 3-fluoro-5-methoxybenzonitrile was as follows: in a 50 mL round-bottomed flask equipped with a magnetic stirrer and a reflux condenser tube, 3-fluoro-5-methoxybenzonitrile (0.62 g, 4.10 mmol), methanol (6.2 mL), and an aqueous sodium hydroxide solution (6.2 mL, 6 N) were added in sequence. The reaction mixture was stirred at 100 °C overnight. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently concentrated under reduced pressure to remove the solvent. The concentrated residue was dissolved in dichloromethane (100 mL) and acidified to pH < 7 with aqueous 1 N hydrochloric acid. The organic phase was separated and washed sequentially with deionized water (100 mL) and saturated saline (100 mL). The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to give 3-fluoro-5-methoxybenzoic acid (0.64 g, 91% yield) as a white solid.
