Cesium carbonate → 5-Bromo-3-(5-(2-methoxyethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-2-ylamino)-1,6-dimethylpyridin-2(1H)-one

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Reaction Steps

A 100-mL round-bottomed flask equipped with a reflux condenser was charged with 327b (392 mg, 2.0 mmol), 327d (562 mg, 2.0 mmol), cesium carbonate (1.30 g, 4.0 mmol), and 1,4-dioxane (20 mL). After bubbling nitrogen through the suspension for 10 minutes, xantphos (115 mg, 0.20 mmol) and tris(dibenzylideneacetone)dipalladium(0) (92 mg, 0.10 mmol) were added. The system was subjected to three cycles of vacuum/nitrogen flush and heated at reflux for 5 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (2×15 mL). The combined filtrate was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with dichloromethane/methanol (80:1 to 30:1) to afford 327e (490 mg, 62%) as a yellow solid. MS-ESI: [M+H]+ 396.2

Provenance & Evidence