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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Kinghorn, A. Douglas
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Publications (3/3 displayed)
- 2023The Cytotoxic Cardiac Glycoside (-)-Cryptanoside A from the Stems of <i>Cryptolepis dubia</i> and Its Molecular Targets.citations
- 2019α-Pyrone and Sterol Constituents of <i>Penicillium aurantiacobrunneum</i>, a Fungal Associate of the Lichen <i>Niebla homalea</i>.citations
- 2017An Intramolecular CAr-H•••O=C Hydrogen Bond and the Configuration of Rotenoids.citations
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article
An Intramolecular CAr-H•••O=C Hydrogen Bond and the Configuration of Rotenoids.
Abstract
Over the past half a century, the structure and configuration of the rotenoids, a group of natural products showing multiple promising bioactivities, have been established by interpretation of their NMR and electronic circular dichroism spectra and confirmed by analysis of single-crystal X-ray diffraction data. The chemical shift of the H-6' <sup>1</sup>H NMR resonance has been found to be an indicator of either a <i>cis</i> or <i>trans</i> C/D ring system. In the present study, four structures representing the central rings of a <i>cis</i>-, a <i>trans</i>-, a dehydro-, and an oxadehydro-rotenoid have been plotted using the <i>Mercury</i> program based on X-ray crystal structures reported previously, with the conformations of the C/D ring system, the local bond lengths or interatomic distances, hydrogen bond angles, and the H-6' chemical shift of these compounds presented. It is shown for the first time that a <i>trans</i>-fused C/D ring system of rotenoids is preferred for the formation of a potential intramolecular C<sub>6'</sub>-H<sub>6'</sub>•••O=C<sub>4</sub> H-bond, and that such H-bonding results in the <sup>1</sup>H NMR resonance for H-6' being shifted downfield.