2-Fluoroethyl 4-methylbenzenesulfonate (1.00 g) was added to a suspension of ethyl 5-(4-fluorophenyl)-4-oxo-1,4-dihydropyridine-3-carboxylate (1.00 g) and cesium carbonate (2.49 g) in DMF (9 ml) at room temperature. The reaction mixture was stirred at 80° C. for two hours. The reaction mixture was returned to room temperature and diluted by adding ethyl acetate. The organic layer was washed with water and brine and dried over sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure, the residue was purified by silica gel column chromatography [ethyl acetate:hexane:methanol=1:1:0->7:3:0->1:0:0->19:0:1 (v/v)] to give 0.35 g of the title compound as an oily substance.
