NEW METABOLITES WITH NEMATOCIDAL AND ANTIMICROBIAL ACTIVITIES FROM THE ASCOMYCETE LACHNUM-PAPYRACEUM (KARST) KARST .6. STRUCTURE DETERMINATION OF NONHALOGENATED METABOLITES STRUCTURALLY RELATED TO MYCORRHIZIN-A

The structure determination of four new biologically active non-haloge nated metabolites isolated from submerged cultures of the ascomycete L achnum papyraceum is described. The compounds are structurally related to the antibiotic mycorrhizin A: (1'Z)-Dechloromycorrhizin A (12), a stereoisomer of dechloromycorrhizin A (5) previously isolated from the same fungus, as well as papyracon A (13), papyracon B (14) and papyra con C (15) containing an exocyclic double bond. The amounts of the lat ter three increased significantly when CaBr2 was added to the culture medium. The structures were determined by spectroscopic methods.