To a solution of tert-butyl 4-(3-fluoro-5-(5-(trifluoromethyl)pyridin-2-yloxy)benzylidene)piperidine-1-carboxylate (585 mg, 0.001 mol) in dry CH2Cl2 (7 mL) cooled to 0° C. was added trifluoroacetic acid (0.99 mL, 0.012 mol). The reaction mixture was stirred for 30 min at 0° C. and then for 1 h at RT. The reaction mixture was quenched with saturated aqueous NaHCO3 and extracted with CH2Cl2 three times. The organic layer was washed with brine, dried over Na2SO4 and evaporated to dryness to give the title compound (469 mg, 100%). 1H NMR (500 MHz, CDCl3): δ 9.82 (m, 1H), 8.43 (s, 1H), 7.95 (d, J=8 Hz, 1H), 7.07 (d, J=9 Hz, 1H), 6.83 (q, J=13.5 Hz, 2H), 6.43 (s, 1H), 3.29 (s, 1H), 3.17 (s, 1H), 2.85 (m, 1H), 2.72 (s, 1H).
