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Synthèse de Nouvelles Nitrones du Type Pyrroline-N-Oxyde - Présentation orale

Abstract : In the field of the design of new free radical scavengers, especially for the ESR study of the role played by oxygen-centered species, such as superoxide and hydroxyl radical, involved in biological processes, the laboratory recently reported the synthesis of a new nitrone, the 2- diethoxyphosphoryl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (DEPMPO). This nitrone was shown to be more efficient than the widely used 2,2-dimethyl-3,4-dihydro-2H-pyrrole-1-oxide (DMPO) : the superoxide spin adduct DEPMPO-OOH has a significantly larger half-life than DMPO-OOH, it does not decompose spontaneously into DEPMPO-OH, and DEPMPO is less sensitive to nucleophilic addition of water than DMPO. Such a behavior is related to the introduction of a -P(O)(OEt)2 group in the 2-position of the ring. In the present work, we tried to investigate the electronic and steric effects of the phosphorus moiety. Then, we prepared 3 new nitrones, the 2-diethoxyphosphorylmethyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (ESP), the 2,2-bisdiethoxyphosphoryl-3,4-dihydro-2H-pyrrole-1-oxide (DPBO) and the 2- ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (EMPO). In ESP, the introduction of a methylene between the ring and the -P(O)(OEt)2 group leads to a decrease of the electrowithdrawing effect, and the behaviour of this nitrone toward the spin trapping of superoxide is more similar to that of DMPO. For DPBO, the second phosphorylated group does not seem to stabilize the DPBO-OOH adduct. In the case of EMPO, the -P(O)(OEt)2 - group is replaced by -CO 2 Et, which has a lower electrowithdrawing effect. The overall behavior of this nitrone is much closer to that of DEPMPO. The most important difference in the spin trap properties of all these nitrones is the persistance of their superoxide spin adduct. Other nitrones are currently investigated in the laboratory.
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https://tel.archives-ouvertes.fr/tel-00003872
Contributor : Gilles Olive <>
Submitted on : Thursday, March 4, 2004 - 7:13:41 PM
Last modification on : Wednesday, April 3, 2019 - 1:56:04 AM
Long-term archiving on: : Friday, April 2, 2010 - 7:13:22 PM

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  • is part of tel-00003786 - Présentation orale de la thèse ....

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Gilles Olive. Synthèse de Nouvelles Nitrones du Type Pyrroline-N-Oxyde - Présentation orale. Autre [q-bio.OT]. Université de droit, d'économie et des sciences - Aix-Marseille III, 1998. Français. ⟨tel-00003872⟩

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