Metabolites of the higher fungi. Part 21. 3-Methyl-3,4-dihydroisocoumarins and related compounds from the ascomycete family xylariaceae

Abstract

Culture solutions of members of the ascomycete family Xylariaceae produce a series of 5-substituted 8-hydroxy-3-methyl-3,4-dihydroisocoumarins as major metabolites. Ramulosin, iso-ochracein, and mellein are produced by three Hypoxylon species and 4-hydroxy iso-ochracein by one species. The antibiotic pyrenophorin is produced by Nummularia broomeiana. The synthesis of 7-formylmellein from mellein is described and the products from the alkaline rearrangement of 5-formylmellein are studied spectroscopically.