Palladium(II) acetate (20 mg) was added to a solution of 5-bromo-3-tert-butoxycarbonylaminothiophene-2-carboxylic acid methyl ester (300 mg), 2-bromo-5-fluoropyridine (235.5 mg), bis(pinacolato)diboron (462.2 mg), tri-t-butylphosphonium tetrafluoroborate (77.64 mg) and cesium carbonate (871.9 mg) in dioxane/water (6 mL/1.5 mL). The solution was heated at 90° C. for 3 h. The reaction solution was then mixed with ethyl acetate and water. The aqueous phase was extracted several times with ethyl acetate. The combined organic phases were dried over sodium sulfate and concentrated. The crude product was purified by preparative HPLC. The product with the molecular weight of 352.39 (C16H17FN2O4S) was obtained in this way; MS (ESI): 353 (M+H+).
