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Preparation of a ε-caprolactonic diterpenoid derivate by unexpected oxidative cleavage/lactonization of 2-oxoaustroeupatol |
| Pablo A. Chacón-Morales1, Juan M. Amaro-Luis1, Luis Beltrán Rojas Fermín2, Rémi Jacquet3, Denis Deffieux3, Laurent Pouységu3, Stéphane Quideau3 |
1 Natural Products Laboratory, Department of Chemistry, Faculty of Science, University of Los Andes, Mérida, 5101, Venezuela;
2 Research Institute, Faculty of Pharmacy and Bioanalysis, University of Los Andes, Mérida, 5101, Venezuela;
3 ISM (CNRS-UMR 5255), Univ. Bordeaux, 351 cours de la Libération, 33405, Talence Cedex, France |
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Abstract From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1. The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites of the substrate yielding the 2-oxoaustroeupatol (2) and 2,19-dioxoaustroeupatol (3). The treatment of 2 with sodium periodate yields a heterocyclic derivative (ε-caprolactone derivate 4) formed by oxidative cleavage and unexpected intramolecular attack of the hydroxymethylene (C-19) oxygen to the ketonic carbon (C-2). A plausible mechanistic pathway for the obtention of compound 4 is proposed.
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| Keywords
Oxidative cleavage
Austroeupatol
NaIO4
IBX
Lactonization
NMR
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| Fund:This work was financially supported by the National Fund of Science, Technology and Innovation (FONACIT) (Grant N° 201300288) within the framework of the project PCP France-Venezuela and by the CDCHTA-ULA (Grant N° C-1935-15-08-ED). Thank are due to Eng. Juan Carmona Arzola, Department of Pharmacognosy and Organic Medicaments, Faculty of Pharmacy and Bioanalysis, University of Los Andes (ULA) for identification of plant material. |
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Corresponding Authors:
Pablo A. Chacón-Morales,E-mail:pablochacon1@gmail.com
E-mail: pablochacon1@gmail.com
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Issue Date: 24 June 2022
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