ACD/Labs Blog

Marine mollusks of the genus Siphonaria, commonly known as false limpets, are shelled, air-breathing herbivores that are believed to have a marine ancestry. When disturbed, siphonariid limpets secrete a sticky white mucus rich in polypropionate secondary metabolites. Specimens were steeped in acetone, and the acetone extract was subjected to extensive chromatography to afford three new polypropionate metabolites. Spectroscopic data of Polypropionate 1 (molecular formula C₂₀H₃₂O₃) are used here to describe the structure elucidation of this compound using CASE techniques.

Le Goff et al reported the structural characterization of two novel alkylhydrazides produced by the bacterial strain Streptomyces sp. LMA-545. The structures were elucidated using 1D and 2D 1H and 13C NMR spectroscopic analysis and high-resolution mass spectrometry. 1H–15N NMR experiments were required for full structural elucidation. Here we investigate the structure elucidation of Geralcin A ( molecular formula C₁₅H₂₄N₂O₅), one of the three isolated novel compounds.

Lee et al have investigated the chemical constituents of the extracts obtained from cultures of the marine-derived fungus Aspergillus sp. SF-5044. This study led to the isolation of new natural products, particularly, an oxepin-containing diketopiperazine-type metabolite named Protuboxepins A (molecular formula C₂₂H₂₃N₃O₃).

Previously Wang et al reported three trace Lycopodium alkaloids, lycojaponicumins A and B with a 5/5/5/5/6 pentacyclic ring system and lycojaponicumin C with a 6/5/5/6 tetracyclic ring system. The same group later described the discovery of structurally unique alkaloid, Lycojaponicumin D (molecular formula was established to be C₁₆H₂₃NO₃), with an unprecedented 5/7/6/6 tetracyclic skeleton formed by an unusual C3-C13 linkage.

An aqueous extract of the roots of I. indigotica has been investigated by Chen and co-workers. In this work, the authors isolated and structurally characterized an indole alkaloid containing unusual dihydrothiopyran and 1,2,4-thiadiazole rings (molecular formula C₁₈H₁₇N₃O₂S₂).

Liao et al isolated and elucidated the structure of a new natural product named as Asperjinone (molecular formula C₂₂H₂₀O₆). Our analysis using ACD/Structure Elucidator resulted in the revision of the structure. The story of the structure revision is described in the Journal of Natural Products.

Ohlendorf and co-workers describe isolation and structure elucidation of Geranylphenazinediol (molecular formula C₂₂H₂₄N₂O₂), a phenazinediol substituted with an isoprenoid side chain. We used ACD/Structure Elucidator to elucidate structure of this new natural product using only its NMR spectroscopic data.

Plaza et al [1] isolated two new unusual depsipeptides, aetheramides A and B. Here we will discuss the computer-assisted structure elucidation (CASE) of aetheramide B (molecular formula C₄₁H₅₄N₂O₉) using ACD/Structure Elucidator.

El Aouad at al isolated a new naphthopyrone (structure 1) named Lasionectrin (molecular formula C₁₉H₂₀O₆) with antiplasmodial properties from fermentation broths of a Lasionectria species. The article constitutes the first account on the isolation of a natural product from fungi of this genus.

M. Cao and co-workers described the isolation and structure elucidation of 10 new alkaloids belonging to the Daphniphyllum alkaloids family. The spectral data presented for one of the compounds, Daphmacromine A (molecular formula C₂₅H₃₇NO₅), were used to challenge ACD/Structure Elucidator.