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

Participants

Reaction Conditions

Reaction Steps

In a 300 mL three-necked 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 stream of nitrogen. After 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, there was added 3.1 mL (27 mmol) of trimethyl borate, and the temperature of the solution was raised to room temperature, and then, the solution was stirred for 10 hours. After a predetermined time, the 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 layer. The extract was washed with a saturated aqueous sodium chloride solution together with the organic layer and then dried over 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 condensed to obtain a solid. The solid was recrystallized with ethyl acetate/hexane; thus, 3.0 g of target pale-yellow powder was obtained with a yield of 66%.

Provenance & Evidence