Synthesis and Properties of Fluorescent Probe for Monosaccharides Based on Exocyclic Ring-Fused Boron Dipyrromethene Dye Substituted with Phenylboronic Ester

Abstract

2-Ethoxycarbonyl-3,4-tetramethylenepyrrole prepared from cyclohexene through an improved twostep procedure was treated with excess lithium aluminum hydride at high temperature to give 2-methyl-3,4-tetramethylenepyrrole. Further condensation with protected 4-formylphenylboronic acid in the presence of trifluoroacetic acid as catalyst,followed by oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone( DDQ) and treatment with triethylamine and boron trifluoride etherate, gives a novel exocyclic ring-fused borondipyrromethene( BDP) dye derivative substituted with phenylboronic ester subunit at the meso-position. The UV-Vis absorption titration and fluorescence titration measurements for BDP dye derivative were carried out to examine its responsibility to D-fructose,D-galactose,and D-glucose at specific p H. The influence of covalent interactions of BDP dye derivative with monosaccharides on its spectroscopic properties can be selectively recognized by both absorption and fluorescence spectra. By the nonlinear curve-fitting analysis of the fluorescence titration data,the association constants Ksof BDP derivative 1 with monosaccharide such as Dfructose,D-galactose,and D-glucose are 1045,445 and 130 L / mol,respectively. Thus BDP derivative 1 can be used as a sensitive and selective fluorescent probe for monosaccharides. Moreover,the sensing mechanism of the fluorescent probe was also preliminarily discussed.