Coscinoderines A–J: Trisubstituted Pyridinium-Containing Norterpenoids Isolated from Coscinoderma bakusi, a Tropical Marine Sponge

Ten new norterpene alkaloids, coscinoderines A–J ( 1 – 10 ), were isolated from the marine sponge Coscinoderma bakusi . Each coscinoderine contains a 1,2,5-trisubstituted pyridinium moiety bearing a terpene unit at the C-2 position. Their structures were elucidated by analysis of NMR and HRMS data, and the absolute stereochemistry of 4 with a 2-methylbutyl group attached to the nitrogen was determined from a comparison of the calculated and measured ECD spectra. The isolation of coscinoderines expands the repertoire of pyridinium alkaloids isolated from marine sponges.