To a solution of cis-4,5-bis-(4-chloro-phenyl)-2-(2-isopropoxy-4-methoxy-phenyl)-4,5-dihydro-imidazole (5 g, 10.98 mmol, example 2) in methylene chloride (50 mL) cooled to 0° C. were added triethylamine (3 mL, 21.96 mL) and phosgene (8.7 mL, 16.47 mmol, ˜20% solution in toluene), respectively. The reaction mixture was stirred at 0° C. for 30 min then the excess reagents and solvent were removed under reduced pressure. The residue was taken in methylene chloride (˜100 mL) and the solution was filtered through a plug of silica gel (˜50 g). The silica gel was washed with 20% ethyl acetate in hexanes. The filtrate was concentrated in vacuo and the residue was purified by flash chromatography (Biotage system, KP-Sil™ 32-63 μm, 60 Å silica gel, eluting with 5%, 10%, 20% ethyl acetate in hexanes) to give rac-4,5-bis-(4-chloro-phenyl)-2-(2-isopropoxy-4-methoxy-phenyl)-4,5-dihydro-imidazole-1-carbonyl chloride as white solids (4.31 g, 76%).
