a) Synthesis of 3-bromo-5-trifluoromethylbenzoic acid (Compound 1.2): 36N sulfuric acid (1.5 mL) and N-bromosuccinimide (NBS, 2.75 g, 15.0 mmol) were sequentially added to a solution of trifluoroacetic acid (TFA, 5 mL) of 3-trifluoromethylbenzoic acid (1.90 g, 10.0 mmol) at room temperature. The reaction mixture was stirred for 30 min and then poured into water (200 mL) under vigorous stirring. The resulting suspension was filtered and the solid product was washed with water and dried to give the target compound 1.2 (2.45 g, 90% yield).
