Hydrochloric Acid → HCID 57525469, compound

Participants

Reaction Steps

5-Fluoro-4-methyl-2-{5-methyl-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridin-4-yl}-1H-benzoimidazole. To a solution of LDA (2.0 M in THF, 18.2 mL, 36.4 mmol, 2.2 equiv) at −78° C. in a oven dried 100 mL round bottom flask was added a solution of 5-bromo-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridine (5.40 g, 16.6 mmol, 1.0 equiv) in THF (20 mL) dropwise. The solution was stirred at −78° C. for 45 min, and then DMF (6.05 mL, 82.8 mmol, 5.0 equiv) was added dropwise. The solution was quenched with satd. aq. NaHCO3 (25 mL) and extracted with chloroform (3×50 mL). The combined extracts were washed with brine and concentrated. The crude residue was diluted with ethanol (5 mL) and treated with sodium bisulfite (2.1 g). The precipitate that formed was collected by vacuum filtration and washed with diethyl ether. The solid was diluted with chloroform (50 mL) and washed with satd. aq. NaHCO3 (50 mL). The organic layer was dried (Na2SO4), filtered and concentrated to afford 5-bromo-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridine-4-carbaldehyde as a mixture with several other unidentified products. A solution of this crude mixture in methanol (15 mL) was treated with conc. H2SO4 (1 mL) and the resulting solution was stirred for 14 h. The mixture was diluted with satd. aq. NaHCO3 (25 mL) and extracted with chloroform (3×25 mL). The combined extracts were concentrated to provide 5-bromo-4-dimethoxymethyl-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridine. A −78° C. solution of the pyridine (2.0 g, 5.0 mmol, 1.0 equiv) in THF (50 mL) was treated with n-butyllithium (2.5 M in hexanes, 2.2 mL, 5.5 mmol, 1.1 equiv). The solution was stirred for 30 min, and then methyl iodide (0.312 g, 5.0 mmol, 1.0 equiv) was added. After 30 min, the reaction was quenched with satd. aq. NaHCO3 (10 mL) and extracted with chloroform (3×25 mL). The combined extracts were dried (Na2SO4), filtered, and concentrated to afford 4-dimethoxymethyl-5-methyl-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridine as a crude mixture. A solution of 4-dimethoxymethyl-5-methyl-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridine (0.64 mg) in THF (100 mL) was treated with 1.0 M HCl (20 mL) and the mixture was stirred for 4 h. The mixture was diluted with satd. aq. NaHCO3 and extracted with chloroform (3×100 mL). The combined extracts were dried (Na2SO4), filtered, and concentrated to provide 5-methyl-2-[4-(1-methyl-piperidin-4-yl)-butoxy]-pyridine-4-carbaldehyde. A portion of this aldehyde (110 mg), 4-fluoro-3-methyl-benzene-1,2-diamine (60 mg), and Na2S2O5 (100 mg) were stirred in DMF (2 mL) at 90° C. for 36 h. The reaction mixture was concentrated and purified by reverse phase HPLC to provide the title compound. MS (electrospray): mass calculated for C24H31FN4O, 410.25; m/z found, 411.5 [M+H]+. 1H NMR (400 MHz, CD3OD): 8.17 (s, 1H), 7.54-7.43 (m, 1H), 7.19-7.05 (m, 2H), 4.34 (t, J=6.4 Hz, 2H), 3.53-3.43 (m, 2H), 3.04-2.89 (m, 2H), 2.84 (s, 3H), 2.53 (s, 3H), 2.43 (s, 3H), 2.06-1.95 (m, 2H), 1.85-1.76 (m, 2H), 1.64-1.29 (m, 7H).

Provenance & Evidence