Ethanol → 6,7-Dichloro-2,3-dimethoxy-5-(4-pyridyl)quinoxaline

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A mixture of 6,7-dichloro-2,3-dimethoxyquinoxaline-5-boronic acid (0.27 g, 0.89 mmol), 4-bromopyridine (0.14 g, 0.89 mmol) and tetrakis(triphenylphosphine)palladium(O) (0.031 g, 0.026 mmol) in a mixture of 2M aqueous sodium carbonate solution (1 mL), ethanol (0.5 mL) and toluene (10 mL) was heated under nitrogen under reflux for 24 hours. After being cooled the mixture was partitioned between water (20 mL) and dichloromethane (20 mL). The phases were separated and the aqueous phase was extracted with dichloromethane (3×50 mL). The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure to give a brown solid which was purified by flash chromatography on silica gel, eluting with hexane:ethyl acetate (3:1, by volume) to afford the title compound (0.113 g, 38%) as a beige solid.

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