ACD/Labs Blog

The spectroscopic data presented for the structure elucidation of Actinobenzoquinoline (molecular formula C₁₉H₁₈N₂O₄) were used to challenge ACD/Structure Elucidator.

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.

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.

A highly brominated compound, 2,3,5,7-tetrabromobenzofuro[3,2-b]pyrrole (molecular formula C₁₀H₃Br₄NO), was extracted from a marine Protobacterium, Pseudoalteromonas sp.

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.

Aquatolide is a humulane-derived sesquiterpenoid lactone isolated from Asteriscus aquaticus. The structure of aquatolide (molecular formula C₁₅H₁₈O₃) contained an extremely rare ladderane substructure.

In a search for novel anti-inflammatory bioactive drug leads from this plant, Su at al isolated from its roots a novel tetrahydrofuran lignan named zanthplanispine, molecular formula C₂₁H₂₂O₈.