Biologically Active Metabolites from Fungi, 4. Palmarumycins CP₁–CP₄ from Coniothyrium palmarum: Isolation, Structure Elucidation, and Biological Activity

Four new penta‐ and hexacyclic antifungal and antibacterial metabolites, the palmarumycins CP 1 –CP 4 ( 1–4 ), were isolated from Coniothyrium palmarum . In these structurally unique antibiotics, a 1,8‐dihydroxynaphthalene unit is connected by a spiroacetal to another partially reduced naphthalene unit. The structure of the pentacyclic palmarumycin CP 3 ( 3 ) was confirmed by X‐ray structure analysis.