pubmed-article:16441085 | pubmed:abstractText | A mixture of cyclohaliclonamines A-E (1-5), novel dimeric, trimeric, tetrameric, pentameric, and hexameric 3-alkylpyridinium alkaloids, was obtained from an Okinawan sponge Haliclona sp. Cyclohaliclonamines C-E are the first tetrameric, pentameric, and hexameric 3-alkylpyridinium alkaloids from natural sources. The structure determination of cyclohaliclonamines is discussed in detail. | lld:pubmed |