2-[4-(2-Phenyl-[1,3]dioxolan-2-yl)-phenyl]-1H-benzoimidazole-5-carboxylic acid amide. To a solution of 2-{4-[2-(4-chloro-phenyl)-[1,3]dioxolan-2-yl]-phenyl}-1H-benzoimidazole-5-carboxylic acid (135 mg, 0.32 mmol) in anhydrous DMF was added carbonyldiimidazole (118 mg, 0.73 mmol). The reaction mixture was stirred under N2 for 30 min and then cooled to 0° C., and ammonium bicarbonate (140 mg, 1.4 mmol) was added. The resulting mixture was allowed to warm to RT and was stirred for 16 h. The mixture was added dropwise to saturated aqueous NH4Cl. The resulting precipitate was collected by filtration and washed with H2O (100 mL) then hexanes (100 mL). The product was dried under vacuum overnight to give the title compound (1.02 mg, 76%). TLC (silica, 1% methanol saturated with ammonia/9% methanol/CH2Cl2): Rf=0.33. HPLC (Method A): Rt=7.42. MS (ESI+): mass calculated for C23H18ClN3O3, 419.1; m/z found, 420.1 [M+H]+. 1H NMR (400 MHz, CD3OD): δ 8.09 (s, 1H), 8.00 (d, J=8.4 Hz, 2H), 7.75-7.72 (dd, J=8.5, 1.5 Hz, 1H), 7.59 (d, J=8.4 Hz, 2H), 7.56 (br d, J=8.7 Hz, 1H), 7.43 (d, J=8.5 Hz, 2H), 7.27 (d, J=8.6 Hz, 2H), 3.99 (s, 4H).
