GENERAL STEPS: 2-bromo-6-chlorobenzoic acid (9.5 g, 0.041 mol) and potassium carbonate (8.6 g, 0.061 mol) were sequentially added to 50 mL of N,N-dimethylformamide and stirred until completely dissolved. Subsequently, iodomethane (11.2 g, 0.081 mol) was slowly added dropwise over 10 minutes. After the dropwise addition, the reaction mixture was continued to be stirred at room temperature for 3.5 hours. Upon completion of the reaction, the reaction mixture was diluted with 500 mL of water and back-extracted with ethyl acetate (3 x 300 mL). The organic phases were combined, washed with 1 M aqueous hydrochloric acid (100 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to afford methyl 2-bromo-6-chlorobenzoate (10.0 g, 99.4% yield). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 7.413 (d, J = 8 Hz, 1H), 7.29 (d, J = 8 Hz, 1H), 7.137 (t, J = 8 Hz, 1H), 3.9 (s, 3H).
