13C-NMR study of the ruthenium(II)-catalyzed degradation of labeled G-factor endoperoxides: proposal of a likely biogenetic pathway and evidence for CO2 release.
G-factor endoperoxides are natural products acting as phytohormones and contribute to root inhibition and frost resistance in Eucalyptus grandis and other Myrtaceae. Several (Z)- and (E)-configured cyclopentane-1,3-dione metabolites of G-factors have been found in some Eucalyptus extracts. Interestingly, these probable metabolites are identical to the products obtained by Ru(II)-catalyzed reduction of G-factors. In the present work, we, thus, studied the mechanism involved in the formation of these compounds by means of in-depth NMR distribution analysis of two differently 13C-labeled G3-factors. The observed CO2 release is underlined, and a comparison with the corresponding Fe(II)-induced degradation of G-factor endoperoxides is made. Also, the type of electron transfer proposed in the two processes is discussed and, tentatively, connected to the role of endoperoxides in plants.
André-Barrès
Christiane
C
Laboratoire de Synthèse et de Physicochimie de Molécules d'Intérêt Biologique UMR CNRS 5068, Université Paul-Sabatier, 118 route de Narbonne, F-31062 Toulouse Cedex 04. candre@chimie.ups-tlse.fr
Baltas
Michel
M
Massou
Stéphane
S
D002245:Carbon Dioxide / Q000032:analysis* / Q000493:pharmacokinetics; D002247:Carbon Isotopes; D002384:Catalysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010545:Peroxides / Q000032:analysis* / Q000493:pharmacokinetics; D010937:Plant Growth Regulators / Q000032:analysis* / Q000493:pharmacokinetics; D012428:Ruthenium / Q000032:analysis* / Q000493:pharmacokinetics
D002247:Carbon Isotopes; D010545:Peroxides; D010937:Plant Growth Regulators; D002245:Carbon Dioxide; D012428:Ruthenium