Ciliatonoid A Structure Elucidation

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).

Fei and co-workers4 isolated Euphorikanin A (molecular formula C₂₀H₂₆O₃), a structurally novel diterpenoid lactone with an unprecedented carbon skeleton featuring a unique tetradecahydrobenzo[cd]-cyclopropa[f ]azulene. Its structure was determined by spectroscopic methods and confirmed by single crystal X-ray analysis.

Monoterpene Indole Alkaloids (MIAs) are found in Alstonia scholaris R. Br. (Apocynaceae) which originates in South Asia. People in the area have been using the bark and leaves as traditional medicines. Zhu and co-workers successfully isolated a new MIA, Alistonitrine A (molecular formula C₂₁H₂₅N₃O₃), which possesses an unprecedented caged monoterpene indole skeleton.

4-Bromobenzoic-biscognienyne A (molecular formula C₂₃H₂₅O₄Br) is relatively simple but its elucidation was chosen as a demonstrated approach, using ACD/Structure Elucidator, in situations where several equiprobable user assumptions ("axioms") should be checked to determine the right structure.

Y.-B. Zhang and co-workers reported four novel matrine-based alkaloids, sophalines A-D. Their structures were elucidated using spectroscopic methods and single-crystal X-ray diffraction. We used the Spectroscopic data for Sophaline C (molecular formula C₂₁H₂₆N₂O₂) to challenge Structure Elucidator.

The fungus Phomopsis sp. TJ507A was recently analyzed by Hu and co-workers. Two functionalized ergostane-type steroids, phomopsterones A and B were isolated. Phomopsterone A (molecular formula C₂₉H₄₂O₆) was chosen for challenging Structure Elucidator.

Using the traditional method of structure elucidation based on analysis of HSQC, HMBC and COSY data, the authors deduced a large part of the molecular structure, but the lack of carbons bearing hydrogen atoms prevented them to assemble the full structure. To alleviate this problem, ACD/Structure Elucidator was utilized in Trichopsistide A, molecular formula C₂₃H₂₉NO₅.

Song et al investigated the chemical constituents of the fruit of S. incarnata. They isolated five novel spirocyclic compounds, spiroschincarins A−E, featuring a unique 1-oxaspiro[6.6]tridecane moiety. Their structures, with absolute configurations, were determined by extensive spectroscopic studies. The structure elucidation of spiroschincarin A (molecular formula C₃₁H₃₈O₁₁) from NMR data was used for challenging ACD/Structure Elucidator.

Chen et al have been looking for novel secondary metabolites from Trichoderma gamsii, a plant endophytic fungus. As a result of this a new polyketide trichoderpyrone (molecular formula C₁₅H₁₇NO₅), containing a unique cyclopentenone−pyrone hybrid skeleton was isolated and its structure was determined by detailed analysis of NMR data.

Wang et al. reported the discovery of 12 new analogs of abyssomicin as metabolites of the Streptomyces species. Amongst them Abyssomicin W (molecular formula C₂₀H₂₆O₈) has an 8/6/6/6 tetracyclic core. Spectroscopic data of this compound were used to challenge ACD/Structure Elucidator Suite.