Nakadomarin A, a Novel Hexacyclic Manzamine-Related Alkaloid from <i>Amphimedon</i> Sponge

Abstract

A novel manzamine-related alkaloid consisting of unprecedented 8/5/5/5/15/6 ring system, nakadomarin A (1), has been isolated from an Okinawan marine sponge Amphimedon sp., and the unique structure containing a furan ring was elucidated on the basis of the spectroscopic data. The relative stereochemistry was deduced from the NOE data and proton couplings, and a plausible biogenetic path of 1 through ircinal A was proposed.