To a solution of 4,5-bis-(4-chloro-phenyl)-2-(2-ethoxy-pyridin-3-yl)-4,5-dihydro-1H-imidazole (475 mg, 1.152 mmol) and triethylamine (321 uL, 2.304 mmol) in methylene chloride (6 mL) cooled to 0° C. was added phosgene (895 uL, 1.728 mmol, 20% solution in toluene, Fluka). The reaction mixture was stirred at 0° C. for 30 min then concentrated to dryness. The residue was taken in ethyl acetate, and the solids were filtered off. The filtrate was concentrated to give crude 4,5-bis-(4-chloro-phenyl)-2-(2-ethoxy-pyridin-3-yl)-4,5-dihydro-imidazole-1-carbonyl chloride as yellow solids (450 mg).
