Synthesis And Secondary Structure Analysis Of Several β-peptides

β-Peptides are made from theβ-amino acid,a new kind of amino acids by adding aα-methylene group intoα-amino acids.Research showed thatβ-peptides present many biological activities which have not found inα-peptides.Moreover,β-peptides could form stable secondary structure,such asα-helix,β-sheet and turns,in certain solvents.These discoveries have brought a broad interest in the research community towardβ-peptides.In this thesis,fiveβ-hexapetides with special side chains were synthesized by liquid-phase peptide synthesis technique.The starting Boc protectedβ-amino acids were prepared via Arndt-Eistert Reaction.Allβ-amino acids andβ-peptides designed were aimed to investigate the side chains' influences on the stability of theβ-peptides' secondary structure.Circular dichroism(CD) results confirmed that theseβ-peptides adopt certain degree of secondary structure in methanol.In addition,an investigation on the coordination properties of oneβ-hexapeptide with thienyl side chains was conducted.Results on this reaearch are summarized as following:1.Six Boc protectedβ-amino acids(Boc-β-Xaa-OH) were synthesized,and were confirmed by ¹H NMR and ¹³C NMR.One of them was first reported.2.Fiveβ-hexapetides have been prepared and characterized by ¹H NMR and low resolution mass spectrometry.The purities of theseβ-peptides were confirmed by RP-HPLC.3.CD results revealed that all the fiveβ-hexapeptides present certain degree of secondary structure in methanol.