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

Participants

Reaction Conditions

Reaction Steps

Into a 500 mL three-neck flask was put 10 g (31 mmol) of 3-bromo-9-phenyl-9H-carbazole. The atmosphere in the flask was replaced with nitrogen. To the flask was added 150 mL of tetrahydrofuran (THF), and 3-bromo-9-phenyl-9H-carbazole was dissolved therein. This solution was cooled to −80° C. Into this solution was dripped 20 mL (32 mmol) of n-butyllithium (a 1.58 mol/L hexane solution) with the use of a syringe. After the dripping was completed, this solution was stirred at the same temperature for 1 hour. After the stirring, 3.8 mL (34 mmol) of trimethyl borate was added to this solution, and the solution was stirred for approximately 15 hours while the temperature of the solution was being brought back to a room temperature. After the stirring, approximately 150 mL (1.0 mol/L) of dilute hydrochloric acid was added to this solution, and then the solution was stirred for 1 hour. After the stirring, an aqueous layer of this mixture was extracted with ethyl acetate. The extract was combined with an organic layer and then washed with a saturated sodium hydrogen carbonate solution. The organic layer was dried with magnesium sulfate. After the drying, this mixture was subjected to gravity filtration. The obtained filtrate was condensed to give an oily light brown substance. This obtained oily substance was dried under reduced pressure to give 7.5 g of a light brown solid, which was the object of the synthesis, in a yield of 86%.

Provenance & Evidence