1,1'-(9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(1,1-diphenylphosphine) → 6-chloro-2-methyl-4-(5-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-2-ylamino)pyridazin-3(2H)-one

Participants

Reaction Conditions

Reaction Steps

A solution of 5-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-2-amine (55.7 mg, 0.37 mmol), 4-bromo-6-chloro-2-methylpyridazin-3(2H)-one (81.8 mg, 0.37 mmol) cesium carbonate (417 mg, 1.28 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (31.8 mg, 0.05 mmol) in dioxane (6 ml) was flushed with argon before tris(dibenzylideneacetone)dipalladium(0) (25.1 mg, 0.03 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 residue was purified by flash chromatography (silica gel, 24 g, 2% to 7% methanol in dichloromethane) to give 6-chloro-2-methyl-4-(5-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-2-ylamino)pyridazin-3(2H)-one (61 mg, 57%) as a light yellow solid.

Provenance & Evidence