Sesquiterpenoids are a class of compounds known to have complex structures, and due to the wide variability of these compounds, it is often challenging to determine the exact structure. Here we discuss the incorrect determination of the structure of Nordine, and later correction; as well as the elucidation of the correct structure using CASE.
The structure of aspochalasin H1 (molecular formula C24H35NO5) was elucidated using 1D and 2D NMR, high-resolution electrospray ionization mass spectroscopy, and comparisons with the reported literature. The CASE-based structure elucidation was carried out by Structure Elucidator Suite in half a minute.
Many corrections of erroneous structures published in the literature have been made with the help of Structure Elucidator Suite. In this example, we were interested to know what the result of using Structure Elucidator for the revision of the plebeianiol A structure would be if the NMR data presented in the work of Liang and collaborators were used.
Analysis of the chemical components of the marine bacterium Saccharomonospora sp. CNQ-490 carried out by Fenical and coworkers yielded three novel compounds, including saccharobisindole (molecular formula C26H28N2O3). Its chemical structure was elucidated by the interpretation of 1D, 2D NMR (HSQC, HMBC and COSY), and high-resolution mass spectrometry (HR-MS) data.
Sung et al. isolated two new caryophyllene-type sesquiterpenoids, rumphellol A and B, from the Rumphella antipathies gorgorian coral. These compounds contain a 9-membered ring fused with a cyclobutane ring, which is rarely observed in natural products. We used ACD/Structure Elucidator to confirm the structure of rumphellol A (molecular formula C15H24O2).
Using the traditional method of structure elucidation based on analysis of HSQC, HMBC and COSY data, the authors deduced a large part of the molecular structure, but the lack of carbons bearing hydrogen atoms prevented them to assemble the full structure. To alleviate this problem, ACD/Structure Elucidator was utilized in Trichopsistide A, molecular formula C23H29NO5.