A mixture of 6-chloropyridazine-3-carboxylic acid (2-cyclopropylethyl)amide (0.500 g, 2.22 mmol), (4-fluorophenyl)piperidin-4-ylmethanone (0.620 g, 2.55 mmol) and triethylamine (0.7 mL, 5 mmol) in acetonitrile (20 mL) was heated to reflux overnight. The solvent was removed in vacuo. The residue was diluted with water, then extracted with ethyl acetate. The residue obtained upon the evaporation of solvent was purified by column chromatography. The title compound was obtained as a white solid in 85% yield (0.270 g). 1H NMR (300 MHz, CDCl3) δ 8.26 (d, J=9.0 Hz, 1H), 8.02-7.93 (m, 2H), 7.65 (d, J=9.0 Hz, 1H), 7.2-7.11 (m, 2H), 6.98 (d, J=9.0 Hz, 1H), 4.55-4.44 (m, 2H), 3.63-3.49 (m, 3H), 3.32-3.19 (m, 2H), 2.5-1.8 (m, 2H), 1.7-1.44 (m, 4H), 0.8-0.67 (m, 1H), 0.52-0.41 (m, 2H), 0.15-0.07 (m, 2H). 13C NMR (75 MHz, CDCl3) δ 200.1, 167.5, 164.1, 163.2, 161.4, 159.9, 158.9, 151.8, 144.6, 132.0, 131.0, 130.9, 129.4, 128.0, 126.9, 116.1, 115.8, 112.2, 44.5, 43.1, 40.0, 39.6, 34.5, 34.3, 27.9, 8.64, 8.6, 4.2. MS (ES+) m/z 397 (M+1).
