Cesium carbonate → (R)-tert-Butyl 4-(6-(5-Bromo-1-methyl-2-oxo-1,2-dihydropyridin-3-ylamino) pyridine-3-yl)-2-methylpiperazine-1-carboxylate

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Reaction Steps

A 50-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 1,4-dioxane (15 mL), 108b (800 mg, 2.7 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one (720 mg, 2.7 mmol), and cesium carbonate (1.76 g, 5.4 mmol). After bubbling nitrogen through the suspension for 3 minutes, Xantphos (78 mg, 0.14 mmol) and tris(dibenzylideneacetone)dipalladium(0) (128 mg, 0.14 mmol) were added. The system was subject to three cycles of vacuum/argon flash and heated at reflux for 3 h. It was then cooled to room temperature and filtered. The filtrate was partitioned between ethyl acetate (30 mL) and water (30 mL). The aqueous layer was separated and extracted with ethyl acetate (50 mL×2). The combined organic layer was washed with brine (50 mL) and dried over anhydrous sodium sulfate. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure. The residue was purified on flash column chromatography eluting with 10:1 dichloromethane/methanol to afford 108c as a yellow solid (624 mg, 47%). LCMS: [M+H]+ 480

Provenance & Evidence