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

Participants

Reaction Conditions

Reaction Steps

A sealed tube was equipped with a magnetic stirrer and charged with 285b (1.1 g, 6.4 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one 5 (1.7 g, 6.4 mmol) and cesium carbonate (4.6 g, 14 mmol) in 1,4-dioxane (64 mL). After bubbling nitrogen through the solution for 30 min, Xantphos (440 mg, 0.8 mmol) and tris(dibenzylideneacetone) dipalladium(0) (400 mg, 0.5 mmol) were added, and the reaction mixture was heated to 100° C. for 16 h. After this time, water (50 mL) and ethyl acetate (50 mL) were added. The aqueous layer was separated and extracted with ethyl acetate (2×50 mL). The combined organic extracts were washed with brine (100 mL) and dried over sodium sulfate. The resulting residue was purified by column chromatography eluting with a gradient of methylene chloride-60:35:5 methylene chloride:diethyl ether:methanol to afford a 28% yield (620 mg) of 285c.

Provenance & Evidence