A solution of 5-(azetidin-1-ylmethyl)-1-methyl-1H-pyrazol-3-amine (292 mg, 1.76 mmol), 4-bromo-6-chloro-2-methylpyridazin-3(2H)-one (393 mg, 1.76 mmol) cesium carbonate (2.00 g, 6.15 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethlxanthene (152 mg, 0.26 mmol) in dioxane (10 ml) was flushed with argon before tris(dibenzylideneacetone)dipalladium(0) (121 mg, 0.13 mmol) was added and the resulting solution was heated at 90° C. for 18 h. The mixture was cooled to room temperature and diluted with dichloromethane (50 mL) and water. The layers were separated and the aqueous layer was extracted with dichloromethane (2×25 mL).The organic layers were combined, dried over magnesium sulfate. The resulting mixture was filtered and concentrated in vacuo. The precipitate formed was isolated by filtration, washed with ether and dried under vacuum to give 4-(5-(azetidin-1-ylmethyl)-1-methyl-1H-pyrazol-3-ylamino)-6-chloro-2-methylpyridazin-3(2H)-one (272 mg, 50%) as a light yellow solid. (M+H)+=309 m/e.
