Malonofungin: an antifungal aminomalonic acid from Phaeoramularia fusimaculans

In screening for antifungal metabolites, a novel compound, malonofungin, exhibiting growth inhibitory activity against Botrytis cinerea (grey mould), has been isolated from fermentations of Phaeoramularia fusimaculans CBS 616.87. Its structure is established as (E)-(3R,4S,5S)-5-acetoxy-2-amino-2-carboxy-3,4-dihydroxy-14-oxoicos++ +-6-enoic acid, representing an addition to the rare class of naturally occurring aminomalonic acids. 1H NMR data and extensive use of CD spectroscopy have been utilized to establish the absolute stereochemistry of malonofungin. The structural and biological relationship of malonofungin to previously reported fungal metabolites is discussed.