To a solution of 4-chloro-5-iodobenzene-1,2-diamine (100 mg, 0.37 mmol) in dioxane (15 ml) and water (5 ml) was added (2,3-dichlorophenyl)boronic acid (141.3 mg, 0.74 mmol), sodium carbonate (118.2 mg, 1.10 mmol) and Pd(PPh3)4 (42.9 mg, 0.04 mmol). The resulting solution was stirred overnight at 100° C. within an inert atmosphere of nitrogen. The resulting solution was concentrated under vacuum and dissolved in water (100 ml) and extracted with ethyl acetate (4×30 ml). The combined organic layers were dried over anhydrous sodium sulfate and concentrated under vacuum to give a residue, which was purified by a silica gel column with between 5% to 25% ethyl acetate in petroleum ether to afford 4-chloro-5-(2,3-dichlorophenyl)benzene-1,2-diamine as a brown solid (92 mg, crude). Finally, the solution of 4-chloro-5-(2,3-dichlorophenyl)benzene-1,2-diamine (100 mg, 0.35 mmol) in pentafluoropropionic acid (35 ml) and hydrochloric acid (conc, 7 ml) was stirred overnight at 100° C. and then concentrated under vacuum. The residue was dissolved in water (100 ml) and extracted with ethyl acetate (4×30 ml), dried over anhydrous sodium sulfate and concentrated. The crude product (500 mg) was purified by Prep-HPLC to afford 5-chloro-6-(2,3-dichlorophenyl)-2-(pentafluoroethyl)-1H-1,3-benzodiazole. TFA salt as a white solid (42 mg).
