4-Bromo-3-dimethylaminomethyl-phenol. 2-Bromo-5-hydroxy-benzaldehyde (5.0 g, 24.9 mmol, 1.0 equiv) and 2.0 M dimethylamine in THF (31 mL, 62 mmol, 2.5 equiv) were stirred in dichloroethane (50 mL) at rt for 1.0 h. Sodium triacetoxyborohydride (15.8 g, 75 mmol, 3.0 equiv) was added, and the mixture was stirred for 3.0 h then poured into satd. aq. NaHCO3. The aqueous mixture was extracted three times with chloroform and the combined extracts were dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified by Method 2 to afford 2.12 g (38%) of the title compound. 1H NMR (400 MHz, CD3OD): 7.36 (dd, J=8.6, 1.8 Hz, 1H), 6.91-6.90 (m, 1H), 6.67-6.62 (m, 1H), 3.53 (d, J=1.3 Hz, 1H), 2.30 (m, 6H). B. {2-Bromo-5-[3-(1-methyl-piperidin-4-yl)-propoxy]-benzyl}-dimethyl-amine. To a solution of 3-(1-methyl-piperidin-4-yl)-propan-1-ol (989 mg, 6.3 mmol, 1.0 equiv) and methanesulfonyl chloride (683 μL, 8.8 mmol, 1.4 equiv) in dichloromethane (12 mL) at 0° C. was added triethylamine (1.57 mL, 11.3 mmol, 1.8 equiv). The reaction mixture, which was allowed to warm to rt, was stirred for 12 h and then poured into satd. aq. NaHCO3. The aqueous mixture was extracted three times with 10% 2-propanol in chloroform and the extract was dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was dissolved in acetonitrile (21 mL) and 4-bromo-3-dimethylaminomethyl-phenol (1.44 g, 6.3 mmol, 1.0 equiv) and cesium carbonate (4.1 g, 12.6 mmol, 2.0 equiv) were added. The mixture was stirred at rt for 12 h, then warmed to 40° C. for 2.0 h, then 50° C. for 1.0 h, and finally 65° C. for 1.5 h. The mixture was poured into satd. aq. NaHCO3 and extracted two times with ethyl acetate and one time with chloroform. The combined extracts were dried (Na2SO4), filtered, and concentrated under reduced pressure. Purification by Method 2 afforded 814 mg (40%) of the title compound. 1H NMR (400 MHz, CD3OD): 7.45 (d, J=8.8 Hz, 1H), 7.05 (d, J=3.1 Hz, 1H), 6.78 (dd, J=8.8, 3.1 Hz, 1H), 3.98 (t, J=6.4 Hz, 2H), 3.58 (s, 2H), 2.93-2.86 (m, 2H), 2.31 (s, 6H), 2.29 (s, 3H), 2.10-1.98 (m, 2H), 1.86-1.73 (m, 4H), 1.49-1.22 (m, 5H). C. {2-(6-Chloro-4-methyl-1H-benzoimidazol-2-yl)-5-[3-(1-methyl-piperidin-4-yl)-propoxy]-benzyl}-dimethyl-amine. To a solution of {2-bromo-5-[3-(1-methyl-piperidin-4-yl)-propoxy]-benzyl}-dimethyl-amine (801 mg, 2.2 mmol, 1.0 equiv) in THF (10 mL) at −78° C., 1.7 M tert-butyllithium in pentane (3.83 mL, 6.5 mmol, 3.0 equiv) was added and the solution was stirred for 15 min. The solution was then warmed to 0° C., stirred for 5 min, and then re-cooled to −78° C. DMF (1.68 mL, 21.7 mmol, 10.0 equiv) was added and the mixture was stirred for 30 min. Water (1.0 mL) was added and the mixture was poured into satd. aq. NaHCO3. The aqueous mixture was extracted three times with ethyl acetate and the combined extracts were dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was partially purified by Method 2 to afford 221 mg of a mixture of 2-dimethylaminomethyl-4-[3-(1-methyl-piperidin-4-yl)-propoxy]-benzaldehyde and several other unidentified products. The crude dimethylaminomethyl-4-[3-(1-methyl-piperidin-4-yl)-propoxy]-benzaldehyde (110 mg) was dissolved in DMF and 5-chloro-3-methyl-benzene-1,2-diamine (54 mg, 0.34 mmol) and Na2S2O5 (85 mg, 0.45 mmol) were added. The mixture was warmed to 90° C. and stirred for 3 h. The reaction mixture was purified by Method 2 to afford 15.2 mg of the title compound. MS (electrospray): mass calculated for C26H35ClN4O, 454.25; m/z found, 455.5 [M+H]+. 1H NMR (400 MHz, CD3OD): 8.07 (d, J=8.6 Hz, 1H), 7.47-7.42 (m, 1H), 7.07-6.97 (m, 3H), 4.04 (t, J=6.4 Hz, 2H), 3.58 (s, 2H), 2.93-2.82 (m, 2H), 2.56 (s, 3H), 2.43 (s, 6H), 2.27 (s, 3H), 2.06-1.93 (m, 2H), 1.87-1.70 (m, 4H), 1.49-1.40 (m, 2H), 1.36-1.21 (m, 3H).
