A mixture of 6-bromo-2-methyl-1-[(4-methylphenyl)sulfonyl]-4-[(phenylmethyl)oxy]-1H-benzimidazole (53.0 g, 112 mmol, STEP 2) and tetrakis(triphenylphosphine)palladium(0) (25.9 g, 22.4 mmol) in 2M dimethylamine tetrahydrofuran solution (580 mL) was stirred at 65° C. under carbon mono-oxide gas (1 atmosphere) for 32 hours. The mixture was cooled to room temperature, and diluted with ethyl acetate (600 mL). The organic mixture was washed with saturated ammonium chloride aqueous solution (800 mL) and brine (500 mL), dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate gradient elution from 1:2 to 1:3) to afford the title compound as a white solid (21.8 g, 42%).
