Cesium carbonate → 5-Bromo-3-(2,3-dimethyl-2H-pyrazolo[3,4-c]pyridin-5-ylamino)-1-methylpyridin-2(1H)-one

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Reaction Steps

A 100-mL round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 5-bromo-2,3-dimethyl-2H-pyrazolo[3,4-c]pyridine 326a from Example 325 (452 mg, 2.0 mmol), 3-amino-5-bromo-1-methylpyridin-2(1H)-one 325a (400 mg, 2.0 mmol), cesium carbonate (1.3 g, 4.0 mmol), and 1,4-dioxane (10 mL). After bubbling nitrogen through the suspension for 5 minutes, BINAP (124 mg, 0.2 mmol) and tris(dibenzylideneacetone)dipalladium(0) (140 mg, 0.2 mmol) were added. The system was subjected to three cycles of vacuum/nitrogen flush and heated at reflux for 2.5 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (3×10 mL). The combined filtrate was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with petroleum ether/ethyl acetate (2/1 to 100% ethyl acetate) to afford 326b (160 mg, 23%) as a yellow solid. MS-ESI: [M+H]+ 348.3

Provenance & Evidence