Download PDF
Synlett 1999; 1999(S1): 893-896
DOI: 10.1055/s-1999-3103
letter
© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Site-Selective Epimerization of a Fungal Cyclodepsipeptide via a 5-Aminooxazole Intermediate

Berndt Oberhauser* , Karl Baumann, Brigitte Grohmann, Hildegard Sperner
  • *Novartis Forschungsinstitut GmbH, Brunner Str. 59, A-1235 Wien, Austria; Fax +43(1)86 63 43 54; E-mail: berndt.oberhauser@pharma.novartis.com
Further Information

Publication History

Publication Date:
31 December 1999 (online)

  PDF Download  Permissions and Reprints All articles of this category

The epimerization of the cyclic depsiheptapeptide 1 at a single amino acid (Leu) was achieved in four steps. After regio-selective thionation of 1 at one of its six amide-bonds, subsequent S-benzylation of the thioamide 2 led to the thioimidate 3, which was converted to the peptide-bridged 5-aminooxazole 5 by an unusual mercury promoted intramolecular cyclization. Re-opening of the oxazole ring by acid hydrolysis regenerated the parent cyclopeptolide framework 6, but preferentially with inverted configuration at leucine.

natural products - cyclodepsipeptide - epimerization - 5-aminooxazole

      >