Structures of Agelasines, Diterpenes Having a 9-Methyladeninium Chromophore Isolated from the Okinawan Marine Sponge Agelas nakamurai Hoshino

Abstract
Novel diterpenes, agelasine-A, -B, -C, -D, -E, and -F were isolated from the Okinawan marine sponge Agelas nakamurai Hoshino and their structures were established to be monocyclic and bicyclic diterpenes having a 9-methyladeninium unit by spectral analyses and chemical transformations.