ACD/Labs Blog

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.

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.

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.

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).

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.

H. Zhang et al observed interesting signals from very minor constituents from F. virosa in their MS analysis. A further fractionation of the fractions returned two extra new alkaloids, one of which, Flueggether A(molecular formula C₂₅H₃₀N₂O₅), is the first example of Securinega alkaloid oligomers which features an ether bond linkage.

The authors reported the production and structure characterization of the novel sesterterpene Astellifadiene. Analysis of the 1H-1H COSY, HMBC, and NOESY correlations established the planar structure as an unprecedented 6-8-6-5-membered tetracyclic ring system. The use of NMR analyses combined with the crystalline sponge method facilitated the unambiguous determination of the Astellifadiene structure (molecular formula C₂₅H₄₀).

Ni et al investigated Cephalotaxus mannii Hook f. which led to the isolation of three new diterpenoids, namely, mannolides A−C, and two new Cephalotaxus troponoids. We used the example of Mannolide A (molecular formula C₂₀H₂₄O₅) to challenge our ACD/Structure Elucidator Suite software.

From investigating the constituents of Sarcandra glabra, P. Wang et al isolated a pair of structurally-related terpene lactones, sarglaperoxides A and B. The original experimental data related to Sarglaperoxide A (molecular formula C₂₃H₂₈O₅) were used to challenge ACD/Structure Elucidator Suite and determine if the software could reliably elucidate this novel structure.