N-[(1S,2R)-2-Hydroxy-1-(hydroxymethyl)propyl]-5-(3-[(1S)-2-methoxy-1-methylethoxy]-5-{[6-(methylsulfonyl)pyridin-3-yl]oxy}phenyl)-1H-pyrrole-2-carboxamide (1.42 g, 2.66 mmol) synthesized in Example (95a) was dissolved in tetrahydrofuran (25 mL), and anhydrous methanesulfonic acid (0.72 g, 3.99 mmol) and triethylamine (1.11 mL, 7.98 mmol) were added at 0° C., followed by stirring for 1 hour under nitrogen atmosphere. The temperature was raised naturally, and stirring was carried out at room temperature for 1 hour, followed by stirring at 50° C. for 2 hours. A saturated aqueous sodium hydrogencarbonate solution (30 mL) was added, and the solution was separated with ethyl acetate (50 mL). The organic layer was washed with saturated brine, and subsequently dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified using silica gel column chromatography (elution solvent: ethyl acetate/hexane=50%-100%) to afford the desired compound (758 mg, yield 55%) as a white solid.
