To a solution of 2-{[1-(cyclopropylmethyl)-2-(2,2-dimethylpropyl)-1H-benzimidazol-5-yl]sulfonyl}-2-methylpropanoic acid (Example 1, Step H, 180 mg, 0.46 mmol), morpholine (Wako Pure Chemical Industries, Ltd., 48 mg, 0.55 mmol), N,N′-diisopropylethylamine (71 mg, 0.55 mmol) in N,N′-dimethylformamide (3 mL) was added diethyl cyanophosphonate (Aldrich, 90 mg, 0.55 mmol) at room temperature. The mixture was stirred at room temperature for 20 h and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:4 as eluent) to afford the title compound (102 mg, 48%) as a white solid.
