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

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Reaction Steps

A 100-mL round-bottomed flask equipped with a reflux condenser was charged with 134b (300 mg, 1.36 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one (364 mg, 1.36 mmol), cesium carbonate (887 mg, 2.7 mmol), and 1,4-dioxane (20 mL). After bubbling nitrogen through the suspension for 10 minutes, xantphos (78 mg, 0.136 mmol) and Pd2(dba)3 (62 mg, 0.068 mmol) were added. The system was subjected to three cycles of vacuum/argon flush and heated at reflux for 5 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (30 mL). The combined filtrate was concentrated under reduced pressure. The solid residue was purified by silica-gel column chromatography eluting with dichloromethane/methanol (80/1 to 30/1) to afford 134c (420 mg, 76%) as a yellow solid. MS-ESI: [M+H]+ 406.0

Provenance & Evidence