Lycojaponicumin D Structure Elucidation

Previously Wang et al reported three trace Lycopodium alkaloids, lycojaponicumins A and B with a 5/5/5/5/6 pentacyclic ring system and lycojaponicumin C with a 6/5/5/6 tetracyclic ring system. The same group later described the discovery of structurally unique alkaloid, Lycojaponicumin D (molecular formula was established to be C₁₆H₂₃NO₃), with an unprecedented 5/7/6/6 tetracyclic skeleton formed by an unusual C3-C13 linkage.

To understand the molecular mechanism underlying the genus-specificity of sperm chemotaxis of ascidians (a type of marine invertebrate filter feeders), Matsumori et al have investigated the structure of a novel compound Ascidia-SAAF 2 (molecular formula C₂₇H₄₄O₁₀S₂Na₂) isolated from the eggs of the ascidian Ascidia sydneiensis.

To understand the molecular mechanism underlying the genus-specificity of ascidians' sperm chemotaxis, Matsumori et al investigated the structure of a novel compound Ascidia-SAAF 2 (molecular formula C₂₇H₄₄O₁₀S₂Na₂), which was isolated from the eggs of the ascidian Ascidia sydneiensis. Utilizing Structure Elucidator Suite allowed the correct structure of unknown, and its configuration upon a double bond to be determined.

Lorente and co-workers isolated two known compounds, pretomaymycin and oxotomaymycin, plus the previously unknown compound barmumycin from the culture broth of the marine actinomycete Streptomyces sp. BOSC-022A. Barmumycin (molecular formula C₁₅H₁₉NO₄)and its diacetate show antitumor activity at micromolar concentrations.

Meng et al. investigated potentially biologically active substances from the chemical constituents of the stems of S. glaucescens. As a result, a novel triterpenoid possessing an unusual 6/7/9-fused tricyclic ring system was obtained, which was designated as Schiglautone A (molecular formula C₃₀H₄₆O₆).

Fan et al isolated two PPAPs, Garcimulins A and B, including a pair of enantiomers [(+)-Garcimulin A and (-)-Garcimulin A)] with the unique caged tetracyclo[5.4.1.11,5.09,13]tridecane skeleton from the leaves and twigs of G. multiflora. The spectroscopic 1D and 2D NMR data used by the authors for structure elucidation of Garcimulin A (molecular formula C₃₈H₅₀O₆) were input into ACD/Structure Elucidator Suite.

Callyspongiolide Macrolides have been reported from various marine macroorganisms, but are especially prominent for marine sponges. Many macrolides display potent anti-proliferative properties against cancer cells, making them promising leads for the development of new chemo-therapeutic agents. Due to their unusual structures and pronounced bioactivity, these compounds continue to be exciting targets for realizing a total...

Bautista et al reinvestigated the chemical composition of S. amarissima. As a result, Teotihuacanin (molecular formula C₂₀H₂₀O₆), an unusual rearranged clerodane diterpene with a new carbon skeleton containing a spiro-10/6 bicyclic system, was isolated from the leaves and flowers of Salvia amarissima.

Wan et al isolated and identified three highly modified and biogenetically related diterpenoids including Pepluacetal (molecular formula C₂₂H₃₂O₄), which has a novel unprecedented fused-ring skeleton containing cyclopentane and cyclobutane rings which rarely occur in natural compounds.

Structures of ciliatonoids A-C, complete with absolute stereochemistry, were characterized by spectroscopic data, X-ray crystallography, and electronic circular dichroism (ECD) analysis. To challenge ACD/Structure Elucidator Suite, Ciliatonoid A (molecular formula C₂₆H₃₂O₅) was used. It featured an unprecedented limonoid architecture by way of a very unique cis-fused central motif (in red).