The first cyclic monomeric 3-alkylpyridinium alkaloid from natural sources: identification, synthesis, and biological activity.

3-Alkylpyridine alkaloids are very common secondary metabolites from marine sponges of the order Haplosclerida. Here, we report on the identification and synthesis of the first cyclic monomeric 3-alkylpyridinium alkaloid from natural sources. Due to the lack of a pure sample of the new compound, structure elucidation had to rely on HPLC and MS(n).