Дибензофурана-4-бороновой кислоты

off-white to beige powder

Dibenzofuran-4-boronic acid is a water-soluble boronic acid, and the boronic acid molecule is a very useful functional group for the preparation of glycosensors. Water-soluble boronic acids that change their fluorescence properties upon binding to sugars are particularly useful as reporter units for carbohydrate fluorescence sensors. Dibenzofuran-4-boronic acid displays distinctive fluorescence changes at three wavelengths when bound to sugars under near-physiological conditions^[1].

In a 300 ml three-necked flask, 7.2 g of 4-bromodibenzofuran was dissolved in -78° C. anhydrous tetrahydrofuran (THF) under an argon atmosphere. Then, 20 ml of an n-butyl lithium-n-hexane solution (1.6 M, 1.1 eq) was added and stirred for 1 hour. 4.23 ml (1.3 eq) of trimethoxyborane (B(OMe)3) was added and stirred for 2 hours, and the temperature of the reaction system was increased to room temperature. 200 ml of 1 N hydrochloric acid was added into the reactant and stirred for 3 hours. An organic layer was separated, and solvents were distilled off. In the crude product thus obtained, hexane was added. Precipitated product was filtered to obtain 4.94 g of dibenzofuran-4-boronic acid as a white solid (yield 80%).