title: Solid-phase synthesis and configurational reassigment of callipeltin E. Implications for the structures of callipeltins A and B.
abstract: Two possible isomers of the natural product callipeltin E (1, 5) were synthesized by using an Fmoc-based solid-phase strategy in 7 steps, in 20% and 26% overall yields, respectively. The (1)H NMR spectrum of synthetic 5 correlated closely with that of the natural product, whereas that of 1 did not, providing confirmation of the configurational reassignment of the N-terminal residue of callipeltin E as D-allothreonine. This result strongly implies that the corresponding residue in the closely related cyclic depsipeptides callipeltins A and B should also be considered a D-allothreonine residue.
authors.affiliation: Department of Chemistry and Cancer Center, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, USA.
authors.forename: Selçuk
authors.initials: S
authors.lastname: Calimsiz
authors.forename: Angel I
authors.initials: AI
authors.lastname: Morales Ramos
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lipton
mesh_terms: D047630:Depsipeptides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry*
chemical_list: D047630:Depsipeptides; D009842:Oligopeptides; D010456:Peptides, Cyclic; C418139:callipeltin A; C516600:callipeltin B; C520377:callipeltin E