A solution of 3-bromo-2-ethynyl-5-(trifluoromethyl)aniline (7.54 g, 28.6 mmol) was slowly added dropwise from its N-methylpyrrolidone (50 mL) solution to an N-methylpyrrolidone (200 mL) solution of potassium tert-butoxide (6.41 g, 57.1 mmol) at 0°C. The reaction mixture was stirred at room temperature for 4 hours. Subsequently, the reaction mixture was poured into brine (500 mL) and extracted with ethyl acetate (4 x 50 mL). The organic layers were combined, washed with brine (100 mL), dried over magnesium sulfate and concentrated. The residue was purified by silica gel column chromatography using a 10% to 25% ethyl acetate/hexane gradient elution to afford 4-bromo-6-trifluoromethyl-1H-indole (7.16 g, 95% yield) as a brown oil. The product was confirmed by 1H-NMR (CDCl3, 400 MHz) and LC/MS (HPLC Method 4): 1H-NMR δ 8.54 (bs, 1H), 7.63 (s, 1H), 7.53 (s, 1H), 7.40 (t, J = 2.8Hz, 1H), 6.66 (t, J = 2.8Hz, 1H); LC/MS: tR = 3.280min, 264.12 (MH)+.
