Synthesis And Application Of Phthalimide Dyes And New Thiol Fluorescent Probes

Cysteine,homocysteine,and glutathione,as biological thiols in living systems,are widely distributed in various organs of the body,playing a vital role in the process of oxidative stress,regulate multiple physiological and pathological processes.Therefore,the assessment of the levels of thiols in biological system is helpful for the early diagnosis of diseases.In recent years,fluorescent probes have been widely used due to their advantages of rapid detection and easy operation.Fluorescent dyes are fluorophores used for fluorescent probes,which dominate the fluorescence band,Stokes shift,and molecular solubility.The fluorophore with a smaller molecular skeleton has better solubility and higher cell permeability,making it more conducive to in vivo and in vitro experiments.This thesis focuses on the derivation of phthaloyl fluorophores and the development of biothiol probes,including:1.A novel phthalimide-based fluorescent probe,Cys518,was designed and synthesized for the detection of cysteine.Starting from 3,4,5,6-tetrafluorophthalic acid,the probe was obtained by a two-step reaction of condensation and substitution.The experimental results show that Cys518 could specifically detect Cys in the presence of other amino acids,and the spectral characterization of product analogs confirm the detection mechanism of Cys518.Besides,the probe Cys518 can realize fluorescent imaging of intracellular cysteine.2.A rhodamine-based fluorescent probe,GSH580,has been designed and synthesized for the specific detection of glutathione(GSH).The probe was obtained by using rhodamine B as the starting material through a two-step reaction.As maleimide works as the GSH recognition site,the probe shows excellent sensitivity for the detection of GSH within 10 minutes.3.A series of multi-band fluorescent dyes based on phthalimide have been designed and synthesized.Using Cys518 as the starting material,11 phthalimide derivatives,PF1-PF11,were synthesized through a one-step reaction.The spectral properties of those compounds in dichloromethane,acetonitrile,ethanol,and PBS were studied.And corresponding theoretical calculations were also carried out.Experimental results show that the new phthalimide-based fluorescent dyes have the advantages of simple synthesis and adjustable fluorescence emission wavelength,indicating these dyes have potential application value.