To a solution of methyl 3-{[(2,4-dichloro-6-methylphenyl)carbamothioyl]amino}-2-[(2-hydroxyethyl)amino]benzoate (300 mg, 0.70 mmol) in tetrahydrofuran (7.0 mL) was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (148 mg, 0.77 mmol) and triethylamine (0.108 mL, 0.77 mmol) at room temperature. The mixture was stirred at 50° C. for 14 hr. Water was added to the reaction mixture at room temperature and the mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, dried over anhydrous magnesium sulfate and concentrated in vacuo to give methyl 2-[(2,4-dichloro-6-methylphenyl)amino]-1-(2-hydroxyethyl)-1H-benzimidazole-7-carboxylate (210 mg, 0.53 mmol, 76%) as a pale yellow solid. To a solution of methyl 2-[(2,4-dichloro-6-methylphenyl)amino]-1-(2-hydroxyethyl)-1H-benzimidazole-7-carboxylate (200 mg, 0.507 mmol) and triethylamine (0.28 mL, 3.8 mmol) was added methanesulfonyl chloride (0.079 mL, 1.02 mmol) at 0° C. The reaction mixture was stirred at 0° C. for 0.5 hr and at room temperature for 14 hr. Then the mixture was warmed to 45° C. and stirred at 45° C. for 8 hr. Water was added to the mixture and the mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The residue was purified by flash chromatography on silica gel eluting with a 25-70% ethyl acetate/n-hexane gradient mixture to give the title compound (170 mg, 0.45 mmol, 89%) as colorless crystals.
