Synthesis And Properties Of Novel Rhodamine-based Fluorescent Probe And Labeling For Bioactive Molecules With Rhodamine

In recent years,many fluorescent probes with high sensitivity and selectivity have been developed.Based on various recognition mechanisms,in-situ detection of metal ions,small molecules or large molecules in living organisms can be achieved.They are widely used in biological,Medicine,environment and other fields.Rhodamine dyes are widely used in the field of fluorescent probes because of their good photophysical properties,unique structure,high extinction coefficient and quantum yield,strong light stability,and long fluorescence emission wavelength.This thesis carried out two parts of work based on rhodamine compounds:In the first part,the asymmetric rhodamine 110/B intermediate was first synthesized.A new fluorescent probe T was designed and synthesized through Mannich reaction in which the the asymmetric rhodamine 110/B worked as amine component,hydroquinone worked as the active hydrogen component and formaldehyde（FA）worked as the aldehyde component.The recognition performance of the probe to FA and hydrazine hydrate（N₂H₄·H₂O）was studied by means of ultraviolet and fluorescence spectroscopy.Experimental studies showed that the probe T responded selectively to FA and（N₂H₄·H₂O）based on the mechanism of inhibition of TICT and“on-off”of Rhodamine.The second part,using Rhodamine B as the fluorophore to fluorescently label the Cyclo（L-Trp-L-Ser）short peptide,using Rhodamine B as the fluorophore to design the N-acyl homoserine lactone（AHLs）signal Molecular fluorescent markers and preliminary studies on their synthesis.The specific research content of this article is summarized as follows:1.Rhodamine 110/B is first prepared by reacting phthalic anhydride,m-aminophenol and m-diethylaminophenol under specific conditions.Then,a novel fluorescent probe T was designed and synthesized by a Mannich reaction with asymmetric rhodamine 110/B precursor as amine component,hydroquinone as active hydrogen component,and formaldehyde as aldehyde component.The structure of this probe T was characterized by proton spectroscopy and mass spectrometry.Under the conditions of DMSO:PBS=1:10（v:v）,pH=7.4,the response of probe T to FA and N₂H₄·H₂O was investigated by ultraviolet and fluorescence spectra.The final study showed that the probe T has good solubility,faster response time and wide p H stable region.Based on the inhibition of the TICT mechanism and the rhodamine on-off mechanism,respectively,it has a good selective recognition of FA and N₂H₄·H₂O and has a certain anti-interference ability.2.According to the basic principle of fluorescent molecular markers,in order to analyze the action mechanism of Cyclo（L-Trp-L-Ser）short peptide by in-situ detection after fluorescent labeling,rhodamine Cyclo（L-Trp-L-Ser）was successfully synthesized.The structure was confirmed by ¹HNMR,¹³CNMR and MS.3.Utilizing the specific structure of AHLs signal molecule imide,it is planned to use this label to have the characteristic of fluorescence response in the presence of Fe³⁺to designed a Rhodamine B based AHLs marker.The AHLs marker can be used for the mechanism study of AHLs action and find new a method for improving antibacterial drugs was designed.The synthesis of two AHLs rhodamine fluorescent markers were preliminary explored.