Reaction Steps
3-[3-(1-Methyl-piperidin-4-yloxy)-propoxy]-benzonitrile. To a mixture of 3-(1-methyl-piperidin-4-yloxy)-propan-1-ol (295 mg, 1.7 mmol, 1.0 equiv) and polymer-supported triphenylphosphine (1.14 g, 3.41 mmol, 2.0 equiv) in THF (40 mL) at 0° C. was added diisopropyl azodicarboxylate (0.67 mL, 3.41 mmol, 2.0 equiv) dropwise via syringe. After 6 h, the mixture was filtered through a glass frit and the filtrate was concentrated. The crude oil was purified by Method 2 to afford 187 mg (40%) of the title compound. MS (electrospray): mass calculated for C16H22N2O2, 274.17; m/z found, 275.4 [M+H]+. 1H NMR (400 MHz, CDCl3): 7.40-7.33 (m, 1H), 7.25-7.21 (m, 1H), 7.17-7.10 (m, 2H), 4.09 (t, J=6.2 Hz, 2H), 3.61 (t, J=6.2 Hz, 2H), 3.34-3.25 (m, 1H), 2.73-2.61 (m, 2H), 2.26 (s, 3H), 2.17-2.00 (m, 4H), 1.94-1.84 (m, 2H), 1.68-1.55 (m, 2H). B. 6-Fluoro-7-methyl-2-{3-[3-(1-methyl-piperidin-4-yloxy)-propoxy]-phenyl}-1H-benzoimidazole. To a stirred solution of 3-[3-(1-methyl-piperidin-4-yloxy)-propoxy]-benzonitrile (0187 g, 0.68 mmol, 1.0 equiv) in toluene (5.0 mL) at 0° C. was added 1.5 M diisobutylaluminum hydride in toluene (1.02 mL, 1.02 mmol, 1.5 equiv). After 3 h, methanol (9 mL) and 1 M H2SO4 (10 mL) were added. The mixture was stirred for 30 min, then 1.0 M NaOH (10 mL) was added, followed by satd. aq. sodium potassium tartrate (40 mL) and dichloromethane (100 mL). After stirring for 30 min, the mixture was extracted three times with chloroform (50 mL) and the combined extracts were washed with brine, dried (Na2SO4), filtered, and concentrated. The residue was partially purified by Method 2 to afford 106 mg of a mixture of 3-[3-(1-methyl-piperidin-4-yloxy)-propoxy]-benzaldehyde and several other unidentified products. A solution of the crude 3-[3-(1-methyl-piperidin-4-yloxy)-propoxy]-benzaldehyde (53 mg), 4-fluoro-3-methyl-benzene-1,2-diamine (27 mg), and Na2S2O5 in DMF was stirred at 90° C. for 18 h. The reaction mixture was loaded directly on silica gel and purified according to Method 2, which afforded 28.7 mg of the title compound. MS (electrospray): mass calculated for C23H28FN3O2, 397.22; m/z found, 398.4 [M+H]+. 1H NMR (400 MHz, CD3OD): 7.64-7.53 (m, 2H), 7.38-7.25 (m, 2H), 7.00-6.85 (m, 2H), 4.06 (t, J=6.1 Hz, 2H), 3.60-3.52 (m, 2H), 3.33-3.19 (br s, 1H), 2.58 (br s, 2H), 2.42 (s, 3H), 2.17-2.03 (m, 5H), 2.01-1.90 (m, 2H), 1.86-1.72 (m, 2H), 1.60-1.42 (m, 2H).
