A mixture of (5-(9H-carbazol-9-yl)pyridin-3-yl)boronic acid (2C) (0.90 g, 3.1 mmol), 2-(5-bromopyridin-3-yl)-1-phenyl-1H-benzo[d]imidazole (1F) (0.856 g, 3.1 mmol), Pd(PPh3)4 (0.18 g, 0.155 mmol) and potassium carbonate (1.07 g, 7.8 mmol) in dioxane/water (20 mL/5 mL) was degassed and heated at about 90° C. overnight under argon atmosphere. The whole was poured into ethyl acetate (100 mL), then washed with brine (50 mL). The organic phase was collected and dried over Na2SO4, absorbed on silica gel, then purified by flash column (dichloromethane/methanol 40:1) to give a light yellow solid (0.78 g), which was purified again by flash column (silica gel, dichloromethane/methanol 50:1) followed by recrystallization in dichloromethane/methanol to give HTH-2, a light yellow solid (0.60 g, 38% yield).
