Amaurones A-K: Polyketides from the Fish Gut-Derived Fungus sp. CMB-F713.

Using a molecular networking guided strategy, chemical analysis of the Australian mullet fish gastrointestinal tract-derived fungus sp. CMB-F713 yielded a family of polyketide pyrones, amaurones A-I (-), featuring an unprecedented carbon skeleton. Structures were assigned to - by detailed spectroscopic analysis (including X-ray analysis of ), biosynthetic considerations, and chemical interconversions. For example, the orthoacetate was unstable when stored dry at room temperature, transforming to the monoacetates and , while mild heating (40 °C) prompted quantitative conversion of to , via an intramolecular -acetylation. Likewise, during handling, the monoacetate was prone to intramolecular -acetylation, leading to an equilibrium mixture with the isomeric monoacetate amaurone J (), confirmed when partial hydrolysis of the diacetate yielded the monoacetates and and the triol amaurone K ().