To a suspension of lithium aluminum hydride (46 mg, 1.22 mmol) in tetrahydrofuran (5 mL) was added a solution of methyl 2-{[1-(cyclopropylmethyl)-2-(2,2-dimethylpropyl)-1H-benzimidazol-5-yl]sulfonyl}-2-methylpropanoate (Step G, 452 mg, 1.11 mmol) in tetrahydrofuran (5 mL) at 0° C. After stirring for 3 h at 0° C., the mixture was quenched with potassium fluoride (210 mg, 3.66 mmol) and sodium sulfate decahydrate (1.57 g, 4.88 mmol) at 0° C. The resulting mixture was filtered through a pad of celite and the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:1 as eluent) to afford the title compound (388 mg, 92%) as a white amorphous.
