New cyclic depsipeptide antibiotics, clavariopsins A and B, produced by an aquatic hyphomycetes, Clavariopsis aquatica: 2. Structure analysis

Abstract

The structures of new cyclic decadepsipeptides, clavariopsins A and B, were determined to be cyclo[-(R)-2-hydroxyisovaleryl-L-pipecolyl-L-MeVal- L-Val-L-MeAsp-L-Melle-L-Melle-Gly-L-MeVal-L-Tyr(OMe)-] and cyclo[-(R)-2- hydroxyisovaleryl-L-pipecoly-L-Val-L-Val-L-MeAsp-L-Melle-L-Melle-Gly-L- MeVal-L-Tyr(OMe)-], respectively, by spectroscopic analyses, especially using 2D NMR techniques. The absolute stereochemistry was elucidated by the advanced Marfey's method and chiral HPLC analysis.