New Cyclic Depsipeptide Antibiotics, Clavariopsins A and B, Produced by an Aquatic Hyphomycetes, Clavariopsis aquatica

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-Mene-L-Melle-Gly-L-MeVal-L-Tyr(OMe)-] and cyclo[-(R)-2-hydroxyisovaleryl-L-pipecolyl-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.