Hydrochloric Acid → 9-Phenyl-9H-carbazole-3-boronic acid

Participants

Reaction Conditions

Reaction Steps

10 g (31 mmol) of 3-bromo-9-phenyl-9H-carbazole was put into a 500 mL three-neck flask. The atmosphere in the flask was substituted with nitrogen. 150 mL of tetrahydrofuran (THF) was added to the three-neck flask and 3-bromo-9-phenyl-9H-carbazole was dissolved. The solution was cooled to −80° C. Into this solution, 20 mL (32 mmol) of n-butyllithium (1.58 mol/L hexane solution) was dropped with a syringe. After the dropping, the solution was stirred at the same temperature for one hour. After the stir, 3.8 mL (34 mmol) of trimethyl borate was added into the solution, and while the temperature of the solution was being increased to room temperature, the solution was stirred for about 15 hours. After the stir, about 150 mL of dilute hydrochloric acid (1.0 mol/L) was added to the solution and stirred for one hour. After the stir, an aqueous layer of the mixture was extracted with ethyl acetate and the extracted solution and an organic layer were washed together with a saturated sodium hydrogen carbonate aqueous solution. The organic layer was dried with magnesium sulfate, and then the mixture was naturally filtrated. The obtained filtrate was concentrated, so that a light-brown oily substance was obtained. The oily substance was dried with pressure reduced, so that 7.5 g of a light-brown solid substance, which was an object, was obtained in a yield of 86%. The synthesis scheme of Step 1 is shown in the following (C-1).

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