PHOMALONE, AN ANTIFUNGAL METABOLITE OF PHOMA-ETHERIDGEI

The metabolites produced by liquid cultures of Phoma etheridgei, a new fungus isolated from black galls of aspen, have been examined. This f ungus is antagonistic to the aspen decay fungus Phellinus tremulae. Th e compound responsible for this antagonism has been isolated and its s tructure elucidated. Phomalone (1) is a previously undescribed natural product that possesses the same carbon skeleton as the Phoma pigmenti vora metabolite LL-D253 alpha The structure was determined by physical methods, mainly H-1 and C-13 NMR. INAPT experiments played an importa nt role. Some chemical transformations of phomalone (1) are described and it is shown by C-13 labelling experiments to be derived from six a cetate units. Phomalone is active against Phellinus tremulae. Compound s 4, 6, 7, and 8 are also new natural products produced by P. etheridg ei.