3-Alkylpyridinium (original) (raw)

3-Alkylpyridinium (3-AP) compounds are natural chemical compounds that are found in marine sponges belonging to the order Haplosclerida. Some polymers derived from 3-APs are anticholinesterase agents and show hemolytic and cytotoxic activities. More than 70 structurally different 3-APs have been isolated from marine sponges. However, not all such sponges contain 3-AP compounds. Variation in content of 3-APs has been detected even within a single sponge species collected from different geographical area. Although 3-APs look structurally quite simple, the structure elucidation by NMR spectroscopy is complicated by the fact that most of the methylene groups in the alkyl chains show the same chemical shift. Therefore, the 3-APs are an ideal test case for a combined approach of NMR spectroscopy