An unusual 1(10 -> 19)abeo steroid from a jellyfish-derived fungus

Abstract A structurally unique C 25 steroid (phomarol) was isolated from a cultured fungus ( Phoma sp.) derived from the giant jellyfish Nemopilema nomurai . Its planar structure and relative configuration were established by analyzing 1D and 2D NMR data, and its absolute configuration was determined using the modified Mosher’s method and ECD calculation. Phomarol is unique with a 7-membered carbocyclic A ring [1(10 → 19) abeo ], an aromatic B ring, and a side chain cyclized to form a fused pentacyclic skeleton.