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ACD/Labs Blog

Mikhail Elyashberg
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.

Mikhail Elyashberg
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.

Sherry Myles
Structure elucidation of complex natural products and new organic compounds remains a challenging problem. To support this endeavor, CASE (computer-assisted structure elucidation) expert systems were developed. These systems are capable of generating a set of all possible structures consistent with an ensemble of 2D NMR data followed by selection of the most probable structure on...

Mikhail Elyashberg
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.

Mikhail Elyashberg
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).

Mikhail Elyashberg
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.

Arvin Moser
Structure Elucidator Tutorial Freeware: a free software package at the undergraduate and graduate levels This manuscript covers various exercises of using a free CASE (computer-assisted structure elucidation) software application “Structure Elucidator”. The purpose of these exercises is to use elucidation software to quickly explore potential candidates given a set of NMR data and a molecular...

Mikhail Elyashberg
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.

Mikhail Elyashberg
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).

ACDLabs
The successful elucidation of an unknown compound’s molecular structure often requires an analyst with profound knowledge and experience of advanced spectroscopic techniques, such as Nuclear Magnetic Resonance (NMR) spectroscopy and mass spec-trometry. The implementation of Computer-Assisted Structure Elucidation (CASE) software in solving for unknown structures, such as isolated natural products and/or reaction impurities, can serve...