a) A mixture of m-toluic acid (15.0 g, 110 mmol), N-bromosuccinimide (19.60 g, 110 mmol) and tert-butyl peroxybenzoate (2.1 mL, 110 mmol) was mixed in carbon tetrachloride (50 mL) and heated to reflux the reaction overnight. Upon completion of the reaction, the mixture was cooled to room temperature and concentrated under reduced pressure. The resulting residue was washed with carbon tetrachloride and subsequently vacuum filtered. The filtrate was evaporated to dryness to afford the white solid product 3-bromomethylbenzoic acid (12.57 g, 53% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 7.93 (m, 2H), 7.43 (m, 2H), 4.55 (s, 2H).
