A mixture of 7-bromo-2-(1-methyl-1H-pyrazol-4-yl)quinoxaline (5.98 mmol), N-[5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-pyridinyl]benzenesulfonamide (6.78 mmol), and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (1:1) (0.18 mmol) in 2M aqueous sodium carbonate (15 mL) and 1,4-dioxane (40 mL) was heated at 100° C. for 22 h. Additional N-[5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-pyridinyl]benzenesulfonamide (0.83 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex (1:1) (0.09 mmol), and 2M aqueous potassium carbonate (3 mL) were added and the reaction mixture was heated at 100° C. for 22 h for complete consumption of starting material. The reaction mixture was cooled, diluted with diethyl ether (30 mL), and filtered through a pad of Celite while rinsing with (2×30 mL) diethyl ether. The organic layer was poured into a separatory funnel containing water (100 mL) and the layers were separated. The aqueous layer was acidified with 6N aqueous HCl until the pH was approximately 7 and then further extracted with (3×200 mL) ethyl acetate. The combined organic layers were dried over sodium sulfate with decolorizing activated carbon, filtered through a pad of Celite while rinsing with (2×100 mL) ethyl acetate, and concentrated in vacuo. The filtrate was separated and the organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo. Recrystallization of the residue from hot ethyl acetate afforded the title product as an ivory solid (804 mg, 30%). Additional product was obtained from the concentrated mother liquors after purification by silica gel chromatography (70-100% ethyl acetate/hexanes) followed by precipitation from cold ethyl acetate (534 mg, 20%). MS(ES)+ m/e 443 [M+H]+.
