Cesium carbonate → 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 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 1,4-dioxane (30 mL), 5-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-2-amine 128b (1.70 g, 11.2 mmol), 4-bromo-6-chloro-2-methylpyridazin-3(2H)-one (2.68 g, 12.0 mmol), and cesium carbonate (7.30 g, 22.4 mmol). After bubbling nitrogen through the suspension for 30 minutes, Xantphos (0.59 g, 1.02 mmol) and tris(dibenzylideneacetone)dipalladium(0) (467 mg, 0.51 mmol) were added. The system was subjected to three cycles of vacuum/argon flush and heated at 90° C. for 2 h. It was then cooled to room temperature and filtered. The filtrate was evaporated in vacuo. The residue was purified by silica-gel column chromatography eluting with 30:1 dichloromethane/methanol to afford 153a (1.9 g, 60%) as a brown solid. LCMS: [M+H]+ 295.1

Provenance & Evidence