Structure Elucidation of Submilligram Quantities of Natural Products - Application to Haliclamines G and H from the Arctic Marine Sponge Haliclona viscosa

Two new haliclamines were identified directly from the crude extract of the Arctic sponge Haliclona viscosa using improved chromatographic conditions and a detailed knowledge about the fragmentation pattern of haliclamines. These are haliclamine G (1) with two alkyl chains of equal length (10 methylene groups) and haliclamine H (2) with alkyl chains of 10 and 12 methylene groups. Due to the limited amount of sponge material available, the haliclamines were not isolated, and the structure elucidation relied on the chromatographic and mass spectrometric comparison with synthetic compounds.