HETEROCYCLIC Β-AMINO ACIDS AS MOLECULAR TOOLS FOR PEPTIDOMIMETIC SYNTHESIS AND ORGANOCATALYSIS

β-Amino acid( AAs) are analogues of α-AAs with a difference: an additional carbon atom between the carboxylic and amine groups. β-AAs are commonly considered not natural amino acids, although there are some examples of this class in nature as secondary metabolites or as components of complex natural products. Being not natural AAs, when they are inserted in a peptide structure they can confer major proteolytic stability to the system compered to natural AAs. In fact, human peptidases do not recognize beta-amino acids and are not able to hydrolyze peptide bond. Moreover β-peptides and α/β hybrid peptides can induce a predictable and well-defined secondary structure, such as helices, strands and loops that may be residue-controlled and biologically active. During the PhD activity the synthesis of non-natural cyclic β-amino acids has been performed. Each of these has been used for different applications as described below: - Synthesis of non-natural 3-Arylmorpholino-β-amino Acid as a PPII Helix Inducer - Synthesis of electrospun fibers using model peptide containing morpholino-β-amino acid scaffolds - Synthesis of nucleobase morpholino β amino acids from ribonucleosides as molecular chimeras for the preparation of photoluminescent materials - Synthesis of non-natural amino acids with Morpholine core as organocatalysts for enantioselective Aldol-condensation reactions - Synthesis of non-natural amino acid with isoxazoline core as β-turn inducer for the preparation of peptidomimetics - Photochemistry cyclization peptide. This part of my thesis was performed during my visiting period at University of Manchester (UK) in Leonori Group.