Under an argon atmosphere, a suspension of 5-bromo-2-methyl-1-(phenylsulfonyl)-1H-pyrrole-3-carbaldehyde (497 mg), 3-pyridineboronic acid (376 mg), sodium carbonate (481 mg) and tetrakis(triphenylphosphine)palladium (89.2 mg) in 1,2-dimethoxyethane (12 mL) and water (6 mL) was stirred at 80° C. for 1 hr. The reaction mixture was cooled to room temperature, water was added, and the mixture was extracted with ethyl acetate. The extract was washed with saturated aqueous sodium hydrogencarbonate solution, water and saturated brine, dried over anhydrous sodium sulfate, filtrated, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane-ethyl acetate=1:4) to give the title compound as a white solid (yield 353 mg, 72%).
