title: A convenient synthesis of difficult medium-sized cyclic peptides by Staudinger mediated ring-closure.
abstract: Novel, efficient and mild preparation of 7- and 8-membered cyclic di- and 10-membered cyclic tripeptides containing α-, β- or γ-amino acid residues is effected by a Staudinger-mediated ring closure. Medium-sized cyclic di- and tripeptides--recognized as difficult targets--were obtained in moderate to good yields according to a straightforward sequence. Empirical force-field calculations were undertaken to determine their conformational behaviors and showed high levels of similarity with X-ray results. A computational study at the B3LYP/6-31+G** level of theory afforded information regarding the impact of the sequence, ring-size and substitution on the activation barriers for the cyclization of azido peptide thioesters.
authors.affiliation: Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA.
authors.forename: Khanh
authors.initials: K
authors.lastname: Ha
authors.forename: Jean-Christophe M
authors.initials: JC
authors.lastname: Monbaliu
authors.forename: Byron C
authors.initials: BC
authors.lastname: Williams
authors.forename: Girinath G
authors.initials: GG
authors.lastname: Pillai
authors.forename: Charles E
authors.initials: CE
authors.lastname: Ocampo
authors.forename: Matthias
authors.initials: M
authors.lastname: Zeller
authors.forename: Christian V
authors.initials: CV
authors.lastname: Stevens
authors.forename: Alan R
authors.initials: AR
authors.lastname: Katritzky
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory
chemical_list: D000596:Amino Acids; D010456:Peptides, Cyclic