To a N2-purged flask was added ′5-[1-[4-(2,4-bis-trifluoromethyl-benzyloxy)-3-methoxy-phenyl]-methylidene]-2-thioxo-thiazolidin-4-one (42 mg, 85 μmol) and DME (4 mL). To the solution was added NaBH3CN (20 mg, 255 μmol) followed by acetic acid (2 mL). The reaction was stirred at rt for 2 h. The reaction solution was then diluted with EtOAc (100 mL), neutralized by successive washings of sat NaHCO3 (100 mL×3), washed with sat. NaCl (100 mL), dried over Na2SO4, filtered and concentrated under reduced pressure. The crude material was chromatographed (SiO2, DCM/MeOH 100:0 to 98:2) to provide intermediate compound (155 mg, 50% yield). 1H NMR (CDCl3) δ 9.29 (1H, br s), 7.99 (1H, d, J=8.1 Hz), 7.94 (1H, s), 7.83 (1H, d, J=8.1 Hz), 6.72-6.81 (3H, m), 5.38 (2H, s), 4.60 (1H, dd, J1=3.9 Hz, J2=9.8 Hz), 3.92 (3H, s), 3.48 (1H, dd, J=3.9 Hz, J2=14.2 Hz), 3.14 (1H, m); MS (ESI) 496 (MH+).
