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ACD/Labs Blog

As a part of an ongoing research for SNTs from Schisandra micrantha, a minor SNT featuring a complex tetracyclo[5.4.0.02,4.03,7]undecane-bridged system, termed lancolide E, was isolated by Shi et al, molecular formula C29H32O10.

5α-cyprinol sulfate was isolated from a methanolic extract of fish bile (Cyprinus carpio) after separation by preparative LC. The molecular mass and the presence of a sulfate group were revealed by ESI–MS/MS in the negative mode, and the molecular formula of the compound was determined as C27H48O8S.

At ACD/Labs, we are celebrating the 20th birthday of ACD/Structure Elucidator, our most powerful computer assisted structure elucidation (CASE) product. Much like a calculator, CASE is a tool for speeding up spectral analysis and verifying the results of de-Novo Structure Elucidation. CASE has made an amazing impact on our ability to elucidate compounds quickly and accurately by NMR, and has helped spectroscopists solve some of the most challenging elucidations. To better understand how CASE will influence research and development in the coming years, let’s look back on how it has evolved these past 20 years with respect to advancements in modern technology.

Investigation of Cystodytes resulted in the isolation of five pyridoacridines, including shermilamines D and E. The structure of another compound, cycloshermilamine D, also isolated from the same tunicate in minute amounts (0.4% of the crude extract) was determined by Koren-Goldshlager et al, molecular formula C21H16N4OS.

Oroidin (C11H10Br2N4O) is a highly proton-deficient bromopyrrole isolated from the sponge Agelas oroides. A CASE solution to this problem was chosen for testing the capability of DFT based NMR chemical shift prediction to distinguish the correct structure when empirical prediction methods fail to suggest the structure reliably.

As part of an ongoing search for new bioactive natural products from the genus Pentas, Abdissa et al isolated three new naphthalenes  from the roots of P. bussei including 2,2′-binaphthralenyl-1,1′-dione, molecular formula C32H28O6.

Honmura and co-workers isolated epoxyroussoenone and used calculated 13C and 1H chemical shifts, NOE data and ECD spectra analysis to define the most probable geometrical and stereoisomer, molecular formula C15H14O7.

Coniothyrione is a natural product with a molecular formula of C14H9ClO6. The ratio of the number of heavy atoms to hydrogen is 2.3 indicating an especially challenging structure elucidation.