Synthesis And Characterization Of Cyclic Peptides

Peptide compounds have been widely used in chemical,biological and medical fields,especially the potential of peptide compounds in the interaction of protein and protein.In recent years,the pharmaceutical industry has attracted wide attention.As bioactive molecules,linear peptides often have low stability of protease,poor cell permeability and so on.In order to overcome the related limitations of linear peptides,cyclic peptide molecules,constructed by cyclization,often have improved bioactivity and drug properties.This paper focuses on the development of peptide cyclization and the application of related bioactive peptides:In the first part,we successfully developed the method of palladium catalyzed C(SP3)-H functionalization to realize ?C arylated modification of the polypeptide N-terminal,and construct a cyclic peptide with ?C-Trp crosslinking structure,and realizing the synthesis of Stephanotic Acid Methyl Ester of the natural product of the cyclic pentapeptideStephanotic Acid Methyl Ester has a specific leucine carbon and C-C bond of tryptophan indole six position carbon.We use palladium catalyzed C(SP3)-H functionalization to achieve a one-step loop of polypeptides that do not introduce foreign guide groups.The core skeleton of the target molecules is obtained succinctly and efficiently,and then the natural products of the target are obtained by simple deprotation and amide condensation derivatizationIn the second part,we designed and synthesized bioactive cyclic peptide compounds containing diaryl tetrazoleskeleton.In previous studies,the fluorescence labeling of polypeptide compounds was usually choosed on the side chains or C-/N-terminal of amino acids.This strategy is simple and does not affect the skeleton structure of polypeptide compounds.However,the biological activity of polypeptide compounds is often closely related to its spatial conformation.If it can regulate the spatial conformation of polypeptide compounds through light signal,it is expected to realize the bioactivity of polypeptide and control the spatial and temporal resolution.In order to explore this possibility,we choose diaryl tetrazoles which can react with olefin as a cytoskeleton structure unit under mild ultraviolet light.A series of cyclic peptide compounds with photofluorescence properties were synthesized,and the conformation and biological activity of cyclic peptide molecules before and after light click reaction were preliminarily explored.