Dimeric Octaketide Spiroketals from the Jellyfish-Derived Fungus Paecilomyces variotii J08NF‑1
Haibo Wang, Jongki Hong, Jun Yin, Hyung Ryong Moon, Yonghong Liu, Xiaoyi Wei, Dong-Chan Oh, Jee H. Jung
Journal of Natural Products
Paeciloketals (1–3), new benzannulated spiroketal derivatives, were isolated from the marine fungus Paecilomyces variotii derived from the giant jellyfish Nemopilema nomurai. Compound 1was present as a racemate and was resolved into enantiopure 1a and 1b by chiral-phase separation on a cellulose column. Compounds 2 and 3, possessing a novel benzannulated spiroketal skeleton, were rapidly interconvertible and yielded an equilibrium mixture on standing at room temperature. The relative and absolute configurations of compounds 2 and 3 were determined by NOESY analysis and ECD calculations. Compound 1 showed modest antibacterial activity against the marine pathogen Vibrio ichthyoenteri.
Circular dichroism, Absolute configuration, Pharmaceutical