To 4-(1-(4-(trifluoromethoxy)phenyl)-1H-pyrazol-3-yl)benzoic acid (0.58 g, 1.67 mmol) in isopropanol (10.7 mL) was added triethylamine (0.30 mL, 2.17 mmol) and diphenylphosphoryl azide (0.47 mL, 2.17 mmol) and the reaction was stirred at room temperature for 16 hours. The orange precipitate that had formed was filtered through a fritted glass funnel, rinsed with isopropanol, and dried in a vacuum oven to provide 4-(1-(4-(trifluoromethoxy)phenyl)-1H-pyrazol-3-yl)benzoyl azide as an orange solid (188 mg, 30%): 1H NMR (400 MHz, DMSO-d6) δ 8.69 (d, J=2.6 Hz, 1H), 8.17-8.11 (m, 2H), 8.09-8.04 (m, 4H), 7.57 (d, J=8.4 Hz, 2H), 7.24 (d, J=2.6 Hz, 1H); 19F NMR (376 MHz, DMSO-d6) δ −56.97; ESIMS m/z 374 ([M+H]+).
