A new depsidone from the neotricone-rich chemotype of the lichenised fungus Usnea fulvoreagens .

Individuals of Usnea fulvoreagens (Parmeliaceae, lichenised Ascomycota), a shrubby corticolous species that is widespread in Europe, East Asia and North America, produce medullary lichen acids in several distinct chemotypic patterns. One such chemotype reportedly contains an unidentified substance as the major secondary metabolite. We isolated this compound from Californian specimens of U. fulvoreagens and identified it as the rare depsidone neotricone. A co-occurring compound, conneotricone, was identified as 4,10-dihydroxy-5-(hydroxymethyl)-8-methyl-3,7-dioxo-1,3-dihydro-7 H -isobenzofuro[4,5- b ][1,4]benzodioxepine-11-carboxylic acid by NMR and HPLC-UV-MS n comparison with the material synthesised from salazinic acid.