title: Solid-phase synthesis of a cyclodepsipeptide: cotransin.
abstract: The first solid-phase synthesis of cotransin--a cyclic depsipeptide having high pharmacological potential--was achieved, by a proper choice of coupling reagents and use of either TBAF or DBU for Fmoc removal to suppress the otherwise dominating, sequence-derived diketopiperazine formation. Starting the assembly from C-terminal lactic acid allowed fast and epimerization-free cyclization in solution. Novel conditions for orthogonal use of the Fmoc/Bsmoc-protection system were discovered, and an unexpected nucleophilic behavior of DBU was observed.
authors.affiliation: Leibniz-Institute of Molecular Pharmacology (FMP), Robert-Rössle-Str.10, D-12135 Berlin, Germany. coin@fmp-berlin.de
authors.forename: Irene
authors.initials: I
authors.lastname: Coin
authors.forename: Monika
authors.initials: M
authors.lastname: Beerbaum
authors.forename: Peter
authors.initials: P
authors.lastname: Schmieder
authors.forename: Michael
authors.initials: M
authors.lastname: Bienert
authors.forename: Michael
authors.initials: M
authors.lastname: Beyermann
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D003500:Cyclization; D005449:Fluorenes / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry; D010456:Peptides, Cyclic / Q000138:chemical synthesis*; D011137:Polystyrenes / Q000737:chemistry
chemical_list: D000596:Amino Acids; D005449:Fluorenes; C016456:N(alpha)-fluorenylmethyloxycarbonylamino acids; D010456:Peptides, Cyclic; D011137:Polystyrenes; C502316:cotransin; D019344:Lactic Acid