4-Fluorobenzonitrile → (-)-4-{2-[2-(4-Chloro-phenyl)-5,6-difluoro-benzoimidazol-1-yl]-2-cyclohexyl-1,1-dimethyl-ethoxy}-benzonitrile

Participants

Reaction Steps

A solution of 1.0 g (2.39 mmol) (−)-1-[2-(4-chloro-phenyl)-5,6-difluoro-benzoimidazol-1-yl]-1-cyclohexyl-2-methyl-propan-2-ol and 0.289 g (2.39 mmol) 4-fluorobenzonitrile (commercially available) in 10 ml anhydrous tetrahydrofuran was cooled down to 0° C. Then, 4.77 ml (2.39 mmol) potassium bis(trimethylsilyl)amide (0.5 M solution in toluene) were added dropwise to the reaction mixture. The cooling bath was removed and the reaction stirred at room temperature for 5 days. The yellow suspension was poured onto 10% aqueous ammonium chloride solution and the phases were separated. The aqueous layer was extracted three times with ethyl acetate, the combined organic layers were washed with brine, dried over magnesium sulfate, filtered and evaporated. The compound was purified twice by silica gel chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting first with n-heptane for 5 min, then with a gradient of dichloromethane:ethyl acetate (100:0 to 90:10). Colorless foam (40%). MS (Turbo Spray): m/z=520.2 [M+H].

Provenance & Evidence