“…The solvent was evaporated under reduced pressure, and the resulting residue was subjected to flash chromatography (98:2 v/v CHCl3/MeOH) to give the bis-imine target molecule 4b as a pale orange glass which was repeatedly evaporated in vacuo with CHCl3 to provide the imine form. Yield ) 85 mg (75%); [R] D 20 ) +734°(c ) 0.05, CHCl3); 1 H NMR (400 MHz, CDCl3) δ 7.68 (d, 2H, J ) 4.4 Hz), 7.49 (s, 2H), 6.80 (s, 2H), 5.19 (br s, 2H), 5.16 (br s, 2H), 4.28 (br s, 4H), 4.15-4.00 (m, 4H), 3.92 (s, 6H), 3.90-3.80 (m, 2H), 3.12 (dd, 2H, J ) 9.0, 15.9 Hz), 2.95 (d, 2H, J ) 15.9 Hz), 2.00-1.85 (m, 4H), 1.72-1.67 (m, 2H); 13 Determination of In Vitro Cytotoxicity. K562 human chronic myeloid leukemia cells were maintained in RPM1 1640 medium supplemented with 10% fetal calf serum and 2 mM glutamine at 37 °C in a humidified atmosphere containing 5% CO 2 and were incubated with a specified dose of drug for 1 h at 37 °C in the dark.…”