Design,synthesis And Application Of The Coumarin-based Fluorescent Probes

Bioactive small molecules,such as HSO₃^-/SO₃^2-,Cl O^-,etc.are closely related to the process of cell development and metabolism,and play a very important role in physiological function and pathological process.However,traditional detection methods(eg.chromatography,chemical titration,electrochemical detection),are difficult to achieve the real-time monitoring of the bioactive small molecules in cells.In comparison,fluorescence probes are a kind of non-invasive detection technology with the advantages of simple operation,high sensitivity,good selectivity,high spatial and temporal resolution,and small interference to living cells or tissue background.Combined with biological imaging technology,fluorescence probes can also realize the visualization detection of the specific enzymes and small bio-molecules in cells,and also have more extensive application in the fields of environment,food and biomedicine.In this thesis,two kinds of coumarin-based fluorescent probes were designed and synthesized for the determination of SO2 derivatives and hypochlorite(Cl O^-).The main research contents of this thesis are as follows:(1)A fluorescence-enhanced probe CISD for the detection of SO2 derivatives was synthesized by 3-acetylcoumarin and 2-methylindole-3-formaldehyde under the catalysis of alkali through the aldol reaction.The probe has high selectivity,low detection limit(262 nm),fast response(<10 s)and stable in the physiological p H.A good linear relationship was obtained with the concentrations of HSO3^-ranging from0 to 80?m.In the case of the probe CISD,HSO₃^-/SO₃^2-can cause a color change and fluorescence enhancement.In addition,the probe has low cytotoxicity,has been successfully applied for imaging exogenous HSO3^-in living cells.(2)Two new ratio fluorescent probes PDC and POC were synthesized by4-(diethylamino)-salicylaldehyde and ethyl 3-oxobutanoate by Knoevenagel condensation followed by Vilsmeier-Haack reaction.Both of them have good water-solubility and show color and fluorescence changes to Cl O^-with fast response(<6 s),good selectivity,and low detection limit.The probes were also employed to image Cl O^-in living cells with low cytotoxicity.Furthermore,the probe PDC has been successfully used to determine the level of Cl O^-in water samples.