CHEMICAL-REACTIVITY OF THE TOXIN OOSPONOL FROM GLOEOPHYLLUM-ABIETINUMWITH NUCLEOPHILIC AGENTS

It is shown that contrary to most isocoumarins the antibiotic compound oosponol from the fungus Gloeophyllum abietinum reacts instantaneousl y with nucleophilic agents like thiol compounds. The reason for this h igh reactivity is due to the vinylogous acid anhydride character of th e compound which is produced by a single oxidation step of the non tox ic biological precursor oospoglycol. One must assume that reactions of oosponol with HS - groups of polypeptides form the basis for its toxi city. The ring-opening reactions were studied in detail with the synth etic analogue 4-acetyl-isocoumarin. The structures of some reaction pr oducts have been analysed mainly with H-1 and C-13 NMR spectroscopy.