Toluene → 2,2'-[2,2'-Bipyridine-5,6-diylbis(biphenyl-4,4'-diyl)]bisbenzoxazole

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Reaction Steps

Into a 100 mL three-neck flask were put 1.4 g (3.0 mmol) of 5,6-bis(4-bromophenyl)-2,2′-bipyridine, 1.3 g (12 mmol) of sodium carbonate, 1.6 g (6.6 mmol) of 4-(benzoxazol-2-yl)phenylboronic acid, 25 ml of toluene, 6 ml of ethanol, 6 ml of water. The mixture was degassed by being stirred under reduced pressure, and the atmosphere in the flask was substituted by nitrogen. 0.14 g (0.12 mmol) of tetrakis(triphenylphosphine)palladium(0) was added, and the mixture was stirred at 80 C.° for 11 hours under a nitrogen stream. After a certain time, the mixture was cooled to room temperature, and the precipitated solid was recovered by suction filtration. The obtained solid was dissolved in chloroform, and washed with water and saturated saline, then the organic layer was dried over magnesium sulfate. The obtained mixture was subjected to gravity filtration, and the obtained filtrate was concentrated to give a solid. A toluene solution of the obtained solid was subjected to suction filtration through Celite (produced by Wako Pure Chemical Industries, Ltd., Catalog No. 531-16855). The filtrate was condensed to give a solid. A suspension in which methanol was added to this solid was irradiated with ultrasonic waves, and subjected to suction filtration to recover the solid. Then, the solid was recrystallized with toluene, so that 1.1 g of a target substance, white powder was recovered in a yield of 54%.

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