Hydrochloric Acid → 4-(3-Phenylquinoxalin-2-yl)phenylboronic acid

Participants

Reaction Conditions

Reaction Steps

In a 300-mL three-neck flask was placed 5.0 g (13 mmol) of 2-(4-bromophenyl)-3-phenylquinoxaline, and the atmosphere in the flask was replaced with nitrogen. There was added 40 mL of tetrahydrofuran, and the mixture was cooled to −78° C. under a nitrogen stream. After the cooling, 10 mL (16 mmol) of 1.6 M n-butyllithium was dripped thereinto, and the mixture was stirred at the same temperature for 1 hour. After a predetermined time, 3.1 mL (27 mmol) of trimethyl borate was added thereto, and the temperature of the reaction solution was raised to room temperature, and then, the solution was stirred for 10 hours. After a predetermined time, the reaction solution was cooled to 0° C., to which 100 mL of 0.1 M hydrochloric acid was added, and the solution was stirred for 1 hour. After a predetermined time, an organic substance was extracted with ethyl acetate from the aqueous phase. The extracted solution combined with the organic phase was washed with brine, and then dried with magnesium sulfate. The mixture was subjected to suction filtration through Celite (produced by Wako Pure Chemical Industries, Ltd., Catalog No. 531-16855). The obtained filtrate was concentrated to give a solid. The solid was recrystallized with ethyl acetate/hexane; thus, 3.0 g of a pale-yellow powder which was a product was obtained in a yield of 66%.

Provenance & Evidence