Synthesis And Properties Of Thieno[3,2-g]indole Derivatives

Fluorescence imaging technology has become one of the most powerful tools for realtime monitoring of targets and biological processes in the natural environment due to its high sensitivity,strong specificity,simple operation,multiple detections at the same time,and strong spatiotemporal sampling capabilities.Therefore,fluorescence imaging technology is widely used in various research fields of modern biomedicine and materials,such as clinical diagnosis,drug delivery discovery,and analyte fluorescent probe response.Because the fluorescence in the long-wavelength spectral region(650-900 nm)has the least phototoxicity to biological components,deep penetration to tissues and minimal autofluorescence to biomolecules,far-infrared and near-infrared fluorescent dyes used in fluorescent probes and biological imaging marking field has obvious advantages.Among them,BODIPY dyes,with excellent photophysical properties,have attracted much attention because of their potential application in fluorescence sensing and biological imaging aera.Therefore,BODIPY dyes that absorb and emit in the long-wavelength spectral region have been extensively studied.For BODIPY dyes,the fusion of aromatic ring strategy can not only enrich the delocalization,but also increase the rigidity of the molecular structure.Therefore,a series of symmetrical and asymmetrical BODIPY fluorescent dyes are designed in order to obtain ideal BODIPY fluorescent dyes with an absorption range in the near-infrared region and with a high fluorescence quantum yield.In the first part,we introduced the progress of BODIPY dyes.In the second part,the synthesis and reaction properties of this new thieno[3,2-g]indole heterocyclic system were studied.The successful formylation of ethyl 6-isopropyl-7-formylthieno[3,2-g]indole-2-carboxylate,resulting in an important precursor 2-8 for the synthesis of asymmetric BODIPY dyes.In addition,the synthesis of ethyl 6-isopropylthieno[3,2-g]indole-2-carboxylate was improved,and a series of thieno[3,2-g]indole derivatives with different substituents at the 6-position were synthesized.In the third part,the 7-position unsubstituted thieno[3,2-g]indole derivatives were used to synthesize a series of symmetrical BODIPY fluorescent dyes,which Photophysical properties were also detected.In the fourth part,a series of asymmetric BODIPY fluorescent dyes with novel structures were synthesized using ethyl 6-isopropyl-7-formyl thieno[3,2-g]indole-2-carboxylate as the precursor.And the photophysical properties of these dyes are also discussed.In the fifth part,aiming at the many shortcomings of the currently reported carbazole-1-carbaldehyde or 1,8-dicarbaldehyde synthesis methods,we successfully completed a new method ich is suitable for large-scale preparation of 3,6-dialkylcarbazole-1-formaldehyde or 1,8-diformaldehyde,laying the foundation for the synthesis and application of its subsequent derivatives.