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α‐Phenyl‐ N ‐ tert ‐butylnitrone‐Type Derivatives Bound to β‐Cyclodextrins: Syntheses, Thermokinetics of Self‐Inclusion and Application to Superoxide Spin‐Trapping
Author(s) -
Bardelang David,
Charles Laurence,
Finet JeanPierre,
Jicsinszky Laszlo,
Karoui Hakim,
Marque Sylvain R. A.,
Monnier Valérie,
Rockenbauer Antal,
Rosas Roseline,
Tordo Paul
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700369
Subject(s) - nitrone , chemistry , spin trapping , moiety , radical , electron paramagnetic resonance , cyclodextrin , covalent bond , adduct , photochemistry , superoxide , stereochemistry , organic chemistry , nuclear magnetic resonance , physics , cycloaddition , catalysis , enzyme
α‐Phenyl‐ N ‐ tert ‐butylnitrone (PBN) derivatives bound to β‐cyclodextrin derivatives have been synthesized. Inclusion of the PBN group into the β‐cyclodextrin moiety is host‐ and temperature‐dependent. In the case of the nitrone linked to permethylated cyclodextrin (Me3CD‐PBN), the thermokinetic parameters are in favour of a slow chemical exchange between a tight and a loose complex. In contrast, 2,6‐di‐ O ‐Me‐β‐cyclodextrin‐grafted PBN (Me2CD‐PBN) exists either in a fast exchange or as a strongly self‐associated complex. The covalent cyclodextrin–PBN compounds have been used to trap carbon and oxygen‐centred free radicals. The self‐associated forms of the β‐CD‐spin‐traps are compatible with effective spin‐trapping, affording spin‐adducts with enhanced EPR signal intensities relative to noncovalent CD–nitrone systems or the nitrone alone. This kind of cyclodextrin‐bound nitrone is the first type of covalent supramolecular spin‐trap and should open new possibilities for the study of biological free radicals in vivo.