(R/S)-tert-Butyl 2-(2-hydroxy-2-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)phenyl)acetamido)ethylcarbamate (Example 51, 80 mg, 0.139 mmol) was dissolved in dichloromethane (5 mL). TFA (1 mL, 12.98 mmol) was added. The reaction mixture was stirred for 30 min. All solvent was removed to provide (R/S)-N-(2-aminoethyl)-2-hydroxy-2-(4-(5-(3-phenyl-4-(trifluoromethyl)isoxazol-5-yl)-1,2,4-oxadiazol-3-yl)phenyl)acetamide, TFA (70 mg, 0.116 mmol, 83% yield): LCMS=474.1 [M+H]+; 1H NMR (400 MHz, methanol-d4) δ ppm 8.62 (1 H, t, J=5.93 Hz), 8.19 (2 H, d, J=8.35 Hz), 7.55-7.76 (7 H, m), 5.20 (1 H, s), 3.39-3.64 (2 H, m), 3.07 (2 H, t, J=6.15 Hz); HPLC peak RT=6.3 min (Method A).
