Synthesis Of Acetophenonyl ?-C-glycoside Derivatives And Their Applications As Fluorescence Probes

C-Glycosides are being used as building blocks for the synthesis of a variety of biologically important natural products and drugs.The interest in C-glycosides lies on the stability of the C-glycosidic linkage,which is resistant to both enzymatic and chemical hydrolysis.Here,we focused on using the C-glycoside ketones as reagents by one step Knoevenagel condensation reactions between monosaccharides and 1,3-diketones based on the previous work,and done some research in C-glycoside methodology,derivatives synthesis and applications in fluorescent recognition.1.Studies of the reactivity of diols in 4,6-O-benzylidene-1-deoxy-1-(2-oxo-2-phenylethyl)-?-D-glucopyranose.The substrate 4,6-O-benzylidene-1-deoxy-1-(2-oxo-2-phenylethyl)-?-D-glucopyranose was synthesized over two steps from D-glucose in the total yield of 62%.The selectivity was systematically studied by two aspects:the choice of electrophilic reagents and reaction conditions.Results indicated that strong electron-withdrawing and large space steric hindrance of esterification reagents tended to form 3-substituted ester,and large space steric hindrance of sulfonation reagents tended to obtain 2-substituted derivatives.2.Synthesis of oximes,oxime-ethers and phenylhydrazones of acetophenonyl?-C-glycosides.We have described a convenient and effective strategy that allowed acetophenonyl ?-C-glycosides to convert to oximes,oxime-ethers and phenylhydrazones using 2,3,4,6-0-acetyl-1-deoxy-1-(2-oxo-2-phenylethyl)-?-D-glucopyranose as model.The method is mild enough for a wide range of carbohydrates.As a result,15 novel C-glycosidic schiff bases were synthesized which had the potential applications for the synthesis of important bioactive molecules,their structures were confirmed by NMR and HRMS analysis.3.Knoevenagel condensation between C-glycoside and active methylene compounds.We have studied the Knoevenagel condensation between newly synthesized 2-C-(2,3,4,6-tetra-O-acetyl-?-D-glucopyranose)-4-formyl-methylbenzene and five active methylene compounds.In the reactions,five unusual fused heterocyclic compounds as promising reactive compounds were synthesized in medium to excellent yield(76-92%).4.The synthesis and spectral properities of chemsensor based on C-glycoside and rhodamine B or fluorescein.Two novel and easily available fluorecence probes based on rhodamine B and ?-C-glycoside were designed and synthesized.The properties of the probes were manifested by UV absorption and fluorecence spectrum to recognize the cations in aqueous solution.Sensor 5.6 showed excellent selectivity for Hg2+ over other metal ions and led to a distinct fluorescence enhancement.The changes of color were obvious under visible and UV light,which could be used for naked-eye detection during the sensing process.Common interferent ions did not show any interference with the Hgg-determination.In addition,another novel probe based on fluorescein and ?-C-glycoside was synthesized.A preliminary study on its spectral characteristic was performed,the effect of pH values and contentration on its spectral characteristic were evaluated.The product had potential application prospect as fluorescent probe in bio-medical field.5.Novel fluorescent probe based on ?-C-glycoside for quantification of bovine serum albumin.Two novel C-glycoside-coumarin fluorescent dyes are reported staring from D-glucose catalyzed by acis or base and subsequent aldol reaction.The fluorescence emission is red-shifted and quenched with the increase in polarity of solvents.Such solvent effect was explained structurely.Dates showed large stokes shifts and lowest fluorescence quantum yields in PBS buffer solutions.Compared to C-pyranyl probe,C-furyl probe was more sensitive towards BSA.Good linear relationship between the fluorescence intensity of C-furyl probe and BSA concentration was found in the range of 0-2.0 mg/mL demonstrating the potential of C-furyl probe for quantitative measurement of BSA.The effect of pH on the the system has been investigated and indicated that the system was pH independent in a wide pH range(pH = 2-9).The probe showed a good selectivity for BSA over other ions and amino acids,which was suggested as high selective and sensitive fluorescent reagents for quantification of BSA in biological science.