N-tert-butylmethanimine N-oxide is an efficient spin-trapping probe for EPR analysis of glutathione thiyl radical

Abstract

The electron spin resonance (EPR) spin-trapping technique allows detection of radical species with nanosecond half-lives. This technique is based on the high rates of addition of radicals to nitrones or nitroso compounds (spin traps; STs). The paramagnetic nitroxides (spin-adducts) formed as a result of reactions between STs and radical species are relatively stable compounds whose EPR spectra represent “structural fingerprints” of the parent radical species. Herein we report a novel protocol for the synthesis of N-tert-butylmethanimine N-oxide (EBN), which is the simplest nitrone containing an α-H and a tertiary α′-C atom. We present EPR spin-trapping proof that: (i) EBN is an efficient probe for the analysis of glutathione thiyl radical (GS•); (ii) β-cyclodextrins increase the kinetic stability of the spin-adduct EBN/•SG; and (iii) in aqueous solutions, EBN does not react with superoxide anion radical (O2−•) to form EBN/•OOH to any significant extent. The data presented complement previous studies within the context of synthetic accessibility to EBN and efficient spin-trapping analysis of GS•.

Hydroxylamine‐Derived Reagent as a Dual Oxidant and Amino Group Donor for the Iron‐Catalyzed Preparation of Unprotected Sulfinamides from Thiols

“…(See SI for details). X‐Band EPR measurements at 100 K of a freeze‐quenched reaction mixture containing N tert Butyl‐α‐phenyl nitrone as a radical spin trap shows an EPR signal at g =2.006, typical of a radical feature (See SI for details) [95, 96] . Combined with the observation that disulfides can be employed as starting materials instead of thiols (see SI), and the requirement for >2 equiv of the hydroxylamine reagent (See SI), we suggest that the first step in our reaction is rapid formation of the disulfide through oxidation with the hydroxylamine‐derived reagent (Scheme 6).…”

Characterization of a non‐thermally operated electrosurgical argon plasma source by electron spin resonance spectroscopy

“…In general, the DMPO oxygen‐centered radical adducts DMPO‐OH, DMPO‐OOH, and DMPO‐H as well as a DMPO carbon‐centered radical adduct DMPO‐R could be identified and discriminated by their hyperfine structure and Landé‐factor after 20 s of MABS treatment of a 0.1 M degassed DPBS‐DMPO solution (Figure ). The detectable DMPO radical adducts and their intermediates principally occur either from reaction of DMPO with (e.g., from plasma gas phase) or • OOH due to accumulation of H 2 O 2 (H 2 O 2 + • OH → • OOH + H 2 O) . Moreover, naturally generated and H 2 O 2 play an important role as intracellular pro‐ and anti‐apoptotic messengers and effectors .…”

Post-synthetic modification of aluminum trimesate and copper trimesate with TiO2 nanoparticles for photocatalytic applications

“…The absence of spin adducts associated with the capture of · O 2 − radicals is probably due to their short half-life of a few seconds and their lower concentration. The DMPO/ · OH spin adduct may be due to a direct formation process involving hydroxyl radicals or a secondary formation process involving superoxide radicals [ 88 ]. This may be another reason for the composites to degrade more MB than IBP and DIC; · OH radicals are the main species derived from the degradation of MB, whereas in · O 2 − radicals play a key role an important role in the degradation of NSAIDs [ 34 , 89 ].…”