To (E)-ethyl 3-(4-(1-(4-(trifluoromethoxy)phenyl)-1H-1,2,4-triazol-3-yl)phenyl)acrylate (C17) (1.95 g, 4.83 mmol) in methanol (25 mL) was added sodium hydroxide (2 N, 10 mL, 20.0 mmol) and the solution was stirred at room temperature overnight. The methanol was evaporated off under reduced pressure, the reagents were diluted with acetonitrile, and additional sodium hydroxide (2 N, 20 mL, 40.0 mmol) was added. The reaction was stirred at room temperature for 5 hours and then acidified with hydrogen chloride (2 N). The white precipitate was vacuum-filtered to afford the title compound as a white solid (1.72 g, 94%): mp 239-241° C.; 1H NMR (400 MHz, DMSO-d6) δ 12.48 (s, 1H), 9.44 (s, 1H), 8.14 (d, J=8.4 Hz, 2H), 8.12-8.05 (m, 2H), 7.85 (d, J=8.4 Hz, 2H), 7.69-7.59 (m, 3H), 6.61 (d, J=16.0 Hz, 1H); 19F NMR (376 MHz, DMSO-d6) δ −56.96; ESIMS m/z 376 ([M+H]+).
