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

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-Try(OMe)-] and cyclo[-(R)-2-hydroxyisovaleryl-L-pipecolyl-L-MeIle-L-MeIle-Gly-L-MeVal-L-Tyr(OME)-], respectively, by spectroscopic analysis, especially using 2D NMR techniques. The absolute stereochemistry was elucidated by the advanced MARFEY'S method and chiral HPLC analysis.