Reaction Steps
3-(1-Methyl-1,2,3,6-tetrahydro-pyridin-4-yl)-propan-1-ol. To a solution of 4-(3-hydroxy-propyl)-1-methyl-pyridinium iodide (28 g, 100.4 mmol, 1.0 equiv) in ethanol (200 mL) at 0° C. was added sodium borohydride (5.7 g, 151 mmol, 1.5 equiv). The reaction mixture, which was allowed to warm to rt, was stirred for 30 min and then poured into water. The aqueous solution was extracted with ethyl acetate and the extract was dried (Na2SO4), filtered, and concentrated to afford 15.2 g (97%) of the title compound. 1H NMR (400 MHz, CD3OD): 5.46-5.41 (m, 1H), 3.56 (t, J=6.6 Hz, 2H), 2.98-2.91 (m, 2H), 2.60 (t, J=5.9 Hz, 2H), 2.35 (s, 3H), 2.21-2.14 (m, 2H), 2.12-2.04 (m, 2H), 1.71-1.62 (m, 2H). B. 2-Methyl-4-[3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4-yl)-propoxy]-benzaldehyde. To a solution of 3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4-yl)-propan-1-ol (2.24 g, 14.5 mmol, 1.0 equiv) and pyridine (1.64 mL, 20.2 mmol, 1.4 equiv) in dichloromethane (50 mL) at 0° C. was added p-toluenesulfonyl chloride (3.85 g, 20.2 mmol, 1.4 equiv). The reaction mixture, which was allowed to warm to rt, was stirred for 12 h and then poured into water. The aqueous mixture was extracted with dichloromethane and the extract was dried (Na2SO4), filtered, and concentrated. The residue was subjected to column chromatography on silica gel (10% methanol in dichloromethane) and the resulting oil was added to a mixture of 4-hydroxy-2-methyl-benzaldehyde (639 mg, 4.69 mmol) and K2CO3 (1.62 g, 11.7 mmol) in DMF and warmed to 100° C. After stirring for 16 h, the mixture was allowed to cool to rt and filtered through a pad of diatomaceous earth. The diatomaceous earth was rinsed with ethyl acetate, and the filtrate was concentrated. The residue was purified by Method 2 to afford 356 mg (9%) of the title compound. 1H NMR (400 MHz, CD3OD): 10.1 (s, 1H), 7.78 (d, J=8.6 Hz, 1H), 6.92 (dd, J=8.6, 2.4 Hz, 1H), 6.84 (d, J=2.1 Hz, 1H), 5.49-5.43 (m, 1H), 4.09 (t, J=6.3 Hz, 2H), 2.97-2.91 (m, 2H), 2.65-2.57 (m, 5H), 2.35 (s, 3H), 2.25-2.16 (m, 4H), 1.99-1.88 (m, 2H). C. 6-Chloro-4-methyl-2-{2-methyl-4-[3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4-yl)-propoxy]-phenyl}-1H-benzoimidazole. This compound was prepared by the method described in General Procedure 3 using 2-methyl-4-[3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4-yl)-propoxy]-benzaldehyde (50 mg, 0.18 mmol, 1.0 equiv), 5-chloro-3-methyl-benzene-1,2-diamine (29 mg, 0.18 mmol, 1.0 equiv), and Na2S2O5 (45.2 mg, 0.24 mmol, 1.3 equiv). Purification by Method 2 afforded 15.7 mg (21%) of the title compound. MS (electrospray): mass calculated for C24H28ClN3O, 409.19; m/z found, 410.4 [M+H]+. 1H NMR (400 MHz, CD3OD): 7.53 (d, J=8.5 Hz, 1H), 7.41 (br s, 1H), 7.08-7.04 (m, 1H), 6.93 (d, J=2.3 Hz, 1H), 6.89 (dd, J=8.5, 2.5 Hz, 1H), 5.49-5.44 (m, 1H), 4.04 (t, J=6.3 Hz, 2H), 2.96-2.91 (m, 2H), 2.64-2.56 (m, 5H), 2.49 (s, 3H), 2.35 (s, 3H), 2.28-2.16 (m, 4H), 1.96-1.88 (m, 2H).
