5-{3-[4-(Azetidin-1-ylcarbonyl)-2-fluorophenoxy]-5-[(1S)-2-methoxy-1-methylethoxy]phenyl}-N-[(2R)-2-hydroxypropyl]-1H-pyrrole-2-carboxamide (464 mg, 0.883 mmol) synthesized in Example (69a) was dissolved in tetrahydrofuran (17 mL), and anhydrous methanesulfonic acid (558 mg, 3.20 mmol) and triethylamine (860 μL, 6.20 mmol) were added, followed by stirring at room temperature for 3 days under nitrogen atmosphere. To the reaction solution, saturated aqueous sodium hydrogencarbonate solution was added, and extraction was carried out with ethyl acetate. The organic layer was washed with saturated brine, and subsequently dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified using silica gel column chromatography (elution solvent: methanol/dichloromethane=3%-9%) to afford the desired compound (228 mg, yield 51%) as a white solid.
