34280-35-8Relevant academic research and scientific papers
Generation of acyloxyl spin adducts from N-tert-butyl-a-phenylnitrone (PBN) and 4,5-dihydro-5,5-dimethylpyrrole 1-oxide (DMPO) via nonconventional mechanisms
Eberson, Lennart,Persson, Ola
, p. 1689 - 1696 (2007/10/03)
The reaction between N-tert-butyl-α-phenylnitrone (PBN) and carboxylic acids has been studied Two mechanisms are discernible: the generation of PBN+ by oxidation of PBN with a photochemically produced excited state [from either 2,4,6-tris(4-methoxyphenyl)pyrylium ion 2+ or tetrachlorobenzoquinone 4], followed by reaction with RCOOH, or the addition of RCOOH to PBN to give a hydroxylamine derivative, followed by thermal oxidation by a weak oxidant. The latter sequence is the Forrester-Hepburn mechanism. In this mechanism, neither 2+ nor 4 is effective as an oxidant, whereas bromine could be used. Thus only oxidants with redox potentials ≥ 0.1 (SCE) are reactive enough to oxidize the intermediate hydroxylamine. This behaviour is in agreement with the redox reactivity of hydroxylamines. For the cylic nitrone, 4,5-dihydro-5,5-dimethylpyrrole 1-oxide (DMPO), acyloxyl spin adducts have been prepared by the photochemical route. The reaction between dibenzoyl peroxide and PBN to give PhCOO-PBN is not cataysed by added PhCOOH. It could be shown that the rate of formation of PhCOO-PBN is compatible with the rate of thermal decomposition of dibenzoyl peroxide. Thus dibenzoyl peroxide does not support the Forrester-Hepburn mechanism, in agreement with its redox potential of ca. -0.2 V.
Mass spectrometry and electron paramagnetic resonance study of free radicals spontaneously formed in nitrone-peracid reactions
Sang, Hong,Janzen, Edward G.,Lewis, Brian H.
, p. 2358 - 2363 (2007/10/03)
Reactions of spin traps (C-phenyl N-tert-butyl nitrone (PBN) and 5,5-dimethyl-2-phenyl-1-pyrroline N-oxide (2-Ph-DMPO)) with peracids have been investigated by both mass spectrometry (MS) and electron paramagnetic resonance (EPR). The peracids m-chloroperbenzoic acid, perbenzoic acid, and perpropionic acid, which can be considered models of biological peracids produced during lipid peroxidation, were found to react with spin traps to spontaneously produce significant amount of aminoxyl radicals. The radical products, as well as the nonradical products were detected and their structures identified by EPR and/or MS. Mechanisms for the formation of these products are proposed.
