Cesium carbonate → 5-Bromo-3-(imidazo[1,2-a]pyridin-7-ylamino)-1-methylpyrazin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

A 100-mL round-bottomed flask equipped with a reflux condenser was charged with imidazo[1,2-a]pyridin-7-amine (665 mg, 5.0 mmol), Cs2CO3 (3.26 g, 10 mmol), 3,5-dibromo-1-methylpyrazin-2(1H)-one (1.86 g, 7.0 mmol), Xantphos (289 mg, 0.50 mmol), Pd2(dba)3 (458 mg, 0.50 mmol), and 1,4-dioxane (30 mL). After bubbling nitrogen through the mixture for 30 minutes, it was heated at 100° C. under nitrogen atmosphere for 16 h. Analysis of the reaction mixture by LCMS showed little starting material remained. The reaction mixture was cooled to room temperature and filtered. The filtrate was diluted with dichloromethane (60 mL) and water (50 mL). The aqueous layer was separated and extracted with dichloromethane (3×20 mL). The combined organic layers was dried over Na2SO4, filtered, and concentrated under reduced pressure. The dark residue was purified by silica-gel column chromatography eluting with dichloromethane/methanol (60/1 to 30/1) to afford 185a (700 mg, 44%) as a light yellow solid. MS-ESI: [M+H]+ 320

Provenance & Evidence