To a solution of 4-{4-chloro-7-(1-ethylpropyl)-2-[(1,3,5-trimethyl-1H-pyrazol-4-yl)amino]-1H-benzimidazol-1-yl}butan-1-ol (Reference Example 38; 10 mg, 0.024 mmol) in pyridine (0.5 mL) was added a solution of methanesulfonyl chloride in tetrahydrofuran (1.0 M, 0.029 mL, 0.029 mmol) at 0° C. The mixture was warmed to room temperature and stirred for 24 hr. Aqueous sodium bicarbonate was added and the mixture was extracted with ethyl acetate. Organic layer was washed with brine, dried over sodium sulfate and concentrated in vacuo. The resulting crude mesylate was dissolved in N,N-dimethylformamide (1 mL) and potassium carbonate (17 mg, 0.12 mmol) was added. The mixture was stirred at 80° C. for 60 hr. The mixture was diluted with ethyl acetate, washed with water and brine, dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by flash chromatography on silica gel eluting with a 50-100% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give the title compound (4.0 mg, 0.010 mmol, 42%) as a colorless amorphous.
