title: A synthetic strategy for the preparation of cyclic peptide mimetics based on SET-promoted photocyclization processes.
abstract: A novel method for the synthesis of cyclic peptide analogues has been developed. The general approach relies on the use of SET-promoted photocyclization reactions of peptides that contain N-terminal phthalimides as light absorbing electron acceptor moieties and C-terminal alpha-amidosilane or alpha-amidocarboxylate centers. Prototypical substrates are prepared by coupling preformed peptides with the acid chloride of N-phthalimidoglycine. Irradiation of these substrates results in the generation of cyclic peptide analogues in modest to good yields. The chemical efficiencies of these processes are not significantly affected by (1) the lengths of the peptide chains separating the phthalimide and alpha-amidosilane or alpha-amidocarboxylate centers and (2) the nature of the penultimate cation radical alpha-heterolytic fragmentation process (i.e., desilylation vs decarboxylation). An evaluation of the effects of N-alkyl substitution on the amide residues in the peptide chain showed that N-alkyl substitution does not have a major impact on the efficiencies of the photocyclization reactions but that it profoundly increases the stability of the cyclic peptide.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Pusan National University, Pusan 609-735, Korea.
authors.forename: Ung Chan
authors.initials: UC
authors.lastname: Yoon
authors.forename: Ying Xue
authors.initials: YX
authors.lastname: Jin
authors.forename: Sun Wha
authors.initials: SW
authors.lastname: Oh
authors.forename: Chan Hyo
authors.initials: CH
authors.lastname: Park
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Park
authors.forename: Charles F
authors.initials: CF
authors.lastname: Campana
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Cai
authors.forename: Eileen N
authors.initials: EN
authors.lastname: Duesler
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Mariano
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D010777:Photochemistry; D010797:Phthalimides / Q000138:chemical synthesis / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D010456:Peptides, Cyclic; D010797:Phthalimides