Toluene → 2-[6-(Dibenzothiophen-4-yl)dibenzothiophen-4-yl]dibenzo[f,h]quinoxaline

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Reaction Steps

Into a 200-mL three-neck flask were put 1.6 g (6.1 mmol) of 2-chlorodibenzo[f,h]quinoxaline, 2.5 g (6.1 mmol) of 4,4′-bidibenzothiophene-6-boronic acid, and 0.19 g (0.62 mmol) of tris(2-methylphosphine)phosphine, and the air in the flask was replaced with nitrogen. To this mixture were added 20 mL of toluene, 10 mL of ethanol, and 6.0 mL of an aqueous solution of potassium carbonate (2.0 mol/L). This mixture was degassed by being stirred while the pressure was reduced. To this mixture, 70 mg (0.31 mmol) of palladium(II) acetate was added. This mixture was stirred at 80° C. under a nitrogen stream for 6 hours to precipitate a solid. The precipitated solid was collected by suction filtration. The collected solid was dissolved in approximately 6.0 L of hot toluene, and this solution was suction-filtered through Celite, alumina, and Florisil. The resulting filtrate was concentrated to give a solid. The solid was recrystallized by HPLC to give a white solid. The obtained solid was washed with hot toluene to give 1.5 g of white powder, which was an objective substance, in 41% yield. Synthesis Scheme (b-3) of Step 3 is shown below.

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