General procedure for the synthesis of 3-bromo-5-trifluoromethylbenzonitrile from 3-bromo-5-(trifluoromethyl)benzamide: 3-bromo-5-(trifluoromethyl)benzamide (420 mg, 1.56 mmol) and 2,4,6-trichloro-1,3,5-triazine (437 mg, 2.35 mmol) were dissolved in N,N-dimethylformamide (DMF, 4 mL). The reaction was stirred at room temperature overnight. A white precipitate was observed during the reaction. Upon completion of the reaction, water (10 mL) was added to the mixture and extracted with ethyl acetate (EA, 20 mL × 2). The organic phases were combined, washed with saturated saline (30 mL), dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure to afford the target compound 3-bromo-5-trifluoromethylbenzonitrile (330 mg, 84% yield) as a brown oil. Its nuclear magnetic resonance hydrogen spectrum (1H NMR, 400 MHz, CDCl3) data were as follows: δ 7.99 (s, 1H), 7.98 (s, 1H), 7.85 (s, 1H).
