To a solution of 1-[9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl](cyclopropyl)methanol (180 mg, 0.426 mmol), methoxyacetic acid (0.049 mL, 0.639 mmol), triethylamine (0.118 mL, 0.852 mmol) and 4-dimethylaminopyridine (78 mg, 0.639 mmol) in tetrahydrofuran (8.0 mL) was added 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (163 mg, 0.852 mmol) at room temperature. The mixture was stirred at room temperature for 24 hr. Saturated aqueous ammonium chloride was added to the reaction mixture and the mixture was extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The residue was purified by flash chromatography on silica gel eluting with a 20-70% ethyl acetate/n-hexane gradient mixture and recrystallization from ethanol to give the title compound (31 mg, 0.0627 mmol, 15%) as colorless crystals.
