The general procedure for synthesizing 2-bromo-3-methylbenzoic acid from 2-amino-3-methylbenzoic acid was as follows: referring to Example 1 (0142), 1.00 g of 2-amino-3-methylbenzoic acid, 8 mL of acetic acid, 4 mL of 50% hydrobromic acid, and 16 mL of water were mixed, followed by the addition of 0.46 g of sodium nitrite and 3 mL of water chilled on ice. After stirring the mixture in an ice bath for 10 minutes, the complete reaction of 2-amino-3-methylbenzoic acid was confirmed by silica gel thin layer chromatography (Spreader: hexane/ethyl acetate = 1/1, Rf value of 0.67 for 2-amino-3-methylbenzoic acid). Next, 1.42 g of copper bromide and 5 mL of water were added and the mixture was heated and reacted at 50 °C for 3 hours. Upon completion of the reaction, water was added to the mixture and the precipitate was collected by filtration to give 1.0 g of 2-bromo-3-methylbenzoic acid. (0143) 1H-NMR (CDCl3) δ (ppm): 2.49 (3H, s), 7.29 (1H, t, J=7.6Hz), 7.42 (1H, d, J=7.2Hz), 7.70 (1H, t, J=3.9Hz).
