Failure to detect hydroxyl radical (.OH)-derived spin adducts of 5,5-dimethyl-1-pyrroline N-oxide in electron spin resonance (ESR) spin trapping experiments has been offered as evidence for the lack of the endogenous capacity of stimulated human phagocytes (neutrophils, monocytes, and monocyte-derived macrophages (MDM] to generate .OH. Recent reports that 5,5-dimethyl-1-pyrroline N-oxide spin a...

J. Phys. Or NMR spin trapping techniques for the detection and, at times, absolute quantification of many oxygenand carbon-centered free radical species. These methods are based on the ability of the nitrone phosphorus compound, 5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO), to react with free radical species and form stable radical adducts, which are suitably detected and ac...

We have proposed, using styrene as a model, a new mechanism for the formation of glutathione conjugates that is independent of epoxide formation but dependent on the oxidation of glutathione to a thiyl radical by peroxidases such as prostaglandin H synthase or horseradish peroxidase. The thiyl radical reacts with styrene to yield a carbon-centered radical which subsequently reacts with molecula...

The radical species underlying the activity of the bioreductive anticancer prodrug, SN30000, have been identified by electron paramagnetic resonance and pulse radiolysis techniques. Spin-trapping experiments indicate both an aryl-type radical and an oxidising radical, trapped as a carbon-centred radical, are formed from the protonated radical anion of SN30000. The carbon-centred radical, produc...

EPR spectroscopy and spin-trapping experiments showed that polymer-encapsulated Au nanoparticles promote aldehyde oxidation via a radical pathway by initiating formation of acyl radicals.

The SET-induced biaryl cross-coupling reaction is established as the first example of a Grignard S(RN)1 reaction. The reaction is examined within the mechanistic framework of dissociative electron transfer in the presence of a Lewis acid. DFT calculations show that the reaction proceeds through a radical intermediate in the form of an Mg ion-radical cage, which eludes detection in trapping expe...

We found, unexpectedly, that the radical form of the carbon-centered quinone ketoxy radical adduct with a recently developed spin-trapping agent BMPO can not only be directly detected and identified using HPLC/high resolution MS, but can also be isolated and purified using semi-preparative HPLC, enabling direct observation of its clean 6-line ESR signal.

Reaction of various alkenes with commercially available N-fluorobenzenesulfonimide (NFSI) and TEMPONa provides the corresponding aminooxygenation products in moderate to good yields. Single electron transfer from readily generated TEMPONa to NFSI allows for clean generation of the corresponding bissulfonylamidyl radical along with TEMPO. N-radical addition to an alkene and subsequent TEMPO trap...

An efficient approach for achieving radical cyclizations by using hydroxamate ester as a coordination tether with Lewis acid was studied. The chiral Lewis acid-mediated cascade radical addition-cyclization-trapping reaction proceeded smoothly with good enantio- and diastereoselectivities, providing various chiral γ-lactams.

It has been suggested that ultraviolet light induces free radical formation in skin, leading to photoaging and cancer. We have demonstrated by electron paramagnetic resonance that the ascorbate free radical is naturally present in unexposed skin at a very low steady state level. When a section of SKH-1 hairless mouse skin in an EPR cavity is exposed to UV light (4,500 J m-2.s-1, Xe lamp, 305 nm...