A solution of 302 mg (1.00 mmol) 2-(5-chloro-2-fluoro-phenyl)-[1,8]naphthyridine-4-boronic acid, 194 mg (1.30 mmol) 2,6-dichloropyrazine and 101 mg (1.2 mmol) sodium bicarbonate in 4 ml DMF and 1 ml water was heated to 80° C. under nitrogen. Then 14.0 mg (0.02 mmol) bis-(triphenylphosphine)-palladium(II)-chloride were added and the reaction mixture was stirred for 16 hours at 80° C. Water was added to the reaction mixture and the resulting precipitate was filtered off. The residue was chromatographed on a silica gel column with dichloromethane/methanol as eluent yielding 2-(5-chloro-2-fluoro-phenyl)-4-(6-chloro-pyrazin-2-yl)-[1,8]naphthyridine as colourless crystals; HPLC-MS: 2.35 min, [M+H] 371.
