title: Attempts toward the synthesis of the peptaibol antiamoebin by using the 'azirine/oxazolone method'.
abstract: The two segments, 1-9 and 10-16, of the peptaibol antibiotic antiamoebin I, i.e., the nonapeptide Ac-Phe-Aib-Aib-Aib-D,L-Iva-Gly-Leu-Aib-Aib-OH (15) and the heptapeptide Z-Hyp-Gln-D,L-Iva-Hyp-Aib-Pro-Pheol (34), have been prepared as mixtures of the epimers containing D,L-Iva. All α,α-disubstituted α-amino acids were introduced by the 'azirine/oxazolone method', in which amino or peptide acids are coupled with the corresponding 2H-azirin-3-amines, followed by selective hydrolysis of the terminal amide bond. The amino acids Hyp and Gln were introduced as Z-protected(4) ) (2S,4R)-4-(tert-butoxy)proline (19) and methyl N-[bis(4-methoxyphenyl)methyl]glutamine (26). Coupling of peptide segments was achieved via the 'mixed anhydride' method, the DCC/HOBt or TBTU/HOBt strategy. The crystal structure of the segment 6-9 was determined by X-ray crystallography and displayed the presence of a β-turn conformation.
authors.affiliation: Organisch-chemisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich.
authors.forename: Pia
authors.initials: P
authors.lastname: Blaser
authors.forename: Werner
authors.initials: W
authors.lastname: Altherr
authors.forename: Anthony
authors.initials: A
authors.lastname: Linden
authors.forename: Heinz
authors.initials: H
authors.lastname: Heimgartner
mesh_terms: D000595:Amino Acid Sequence; D001389:Azirines / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D010081:Oxazolone / Q000737:chemistry*; D054848:Peptaibols; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000235:genetics
chemical_list: D001389:Azirines; D054848:Peptaibols; D010455:Peptides; C006596:antiamoebin; D010081:Oxazolone