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Theoretical NMR correlations based Structure Discussion
The constitutional assignment of natural products by NMR spectroscopy is usually based on 2D NMR experiments like COSY, HSQC, and HMBC. The actual difficulty of the structure elucidation problem depends more on the type of the investigated molecule than on its size. The moment HMBC data is involved...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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BioMed Central
2011
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3162559/ https://www.ncbi.nlm.nih.gov/pubmed/21797997 http://dx.doi.org/10.1186/1758-2946-3-27 |
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author | Junker, Jochen |
author_facet | Junker, Jochen |
author_sort | Junker, Jochen |
collection | PubMed |
description | The constitutional assignment of natural products by NMR spectroscopy is usually based on 2D NMR experiments like COSY, HSQC, and HMBC. The actual difficulty of the structure elucidation problem depends more on the type of the investigated molecule than on its size. The moment HMBC data is involved in the process or a large number of heteroatoms is present, a possibility of multiple solutions fitting the same data set exists. A structure elucidation software can be used to find such alternative constitutional assignments and help in the discussion in order to find the correct solution. But this is rarely done. This article describes the use of theoretical NMR correlation data in the structure elucidation process with WEBCOCON, not for the initial constitutional assignments, but to define how well a suggested molecule could have been described by NMR correlation data. The results of this analysis can be used to decide on further steps needed to assure the correctness of the structural assignment. As first step the analysis of the deviation of carbon chemical shifts is performed, comparing chemical shifts predicted for each possible solution with the experimental data. The application of this technique to three well known compounds is shown. Using NMR correlation data alone for the description of the constitutions is not always enough, even when including (13)C chemical shift prediction. |
format | Online Article Text |
id | pubmed-3162559 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-31625592011-08-27 Theoretical NMR correlations based Structure Discussion Junker, Jochen J Cheminform Preliminary Communication The constitutional assignment of natural products by NMR spectroscopy is usually based on 2D NMR experiments like COSY, HSQC, and HMBC. The actual difficulty of the structure elucidation problem depends more on the type of the investigated molecule than on its size. The moment HMBC data is involved in the process or a large number of heteroatoms is present, a possibility of multiple solutions fitting the same data set exists. A structure elucidation software can be used to find such alternative constitutional assignments and help in the discussion in order to find the correct solution. But this is rarely done. This article describes the use of theoretical NMR correlation data in the structure elucidation process with WEBCOCON, not for the initial constitutional assignments, but to define how well a suggested molecule could have been described by NMR correlation data. The results of this analysis can be used to decide on further steps needed to assure the correctness of the structural assignment. As first step the analysis of the deviation of carbon chemical shifts is performed, comparing chemical shifts predicted for each possible solution with the experimental data. The application of this technique to three well known compounds is shown. Using NMR correlation data alone for the description of the constitutions is not always enough, even when including (13)C chemical shift prediction. BioMed Central 2011-07-28 /pmc/articles/PMC3162559/ /pubmed/21797997 http://dx.doi.org/10.1186/1758-2946-3-27 Text en Copyright ©2011 Junker; licensee Chemistry Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Preliminary Communication Junker, Jochen Theoretical NMR correlations based Structure Discussion |
title | Theoretical NMR correlations based Structure Discussion |
title_full | Theoretical NMR correlations based Structure Discussion |
title_fullStr | Theoretical NMR correlations based Structure Discussion |
title_full_unstemmed | Theoretical NMR correlations based Structure Discussion |
title_short | Theoretical NMR correlations based Structure Discussion |
title_sort | theoretical nmr correlations based structure discussion |
topic | Preliminary Communication |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3162559/ https://www.ncbi.nlm.nih.gov/pubmed/21797997 http://dx.doi.org/10.1186/1758-2946-3-27 |
work_keys_str_mv | AT junkerjochen theoreticalnmrcorrelationsbasedstructurediscussion |