55482-05-8

Upstream product

• 3376-24-7 N-tert-butyl-α-phenylnitrone 
• 3376-24-7 (Z)-N-benzylidene-2-methylpropan-2-amine oxide 

Downstream Products

• 22665-15-2 tert-butylhydroaminoxyl 
• 100-52-7 benzaldehyde 

Relevant academic research and scientific papers

Using cyclodextrins to encapsulate oxygen-centered and carbon-centered radical adducts: The case of DMPO, PBN, and MNP spin traps

We present electron spin resonance (ESR) experiments that describe the interaction of β-cyclodextrin (β-CD) with spin adducts of three spin traps: 5,5-dimethyl-1-pyrroline N-oxide (DMPO), N-tert-butyl-α- phenylnitrone (PBN), and 2-methyl-2-nitrosopropane

Substituent effect on the rate of the hydroxyl and phenyl radical spin trapping with nitrones

Hydroxyl and phenyl radical spin trapping rates by α-phenyl-N-t-butylnitrone (PBN, N-benzylidene-t-butylamine N-oxide) and its analogs were determined using a competitive trapping method. Hydroxyl radical was generated from hydrogen peroxide in water usin

Oxidations by the reagent "O2-H2O2-vanadium derivative-pyrazine-2-carboxylic acid". Part 12. Main features, kinetics and mechanism of alkane hydroperoxidation

Various combinations of vanadium derivatives (n-Bu4NVO3 is the best catalyst) with pyrazine-2-carboxylic acid (PCA) catalyse the oxidation of saturated hydrocarbons, RH, with hydrogen peroxide and air in acetonitrile solution to produce, at temperatures V(PCA)(H2O2) → VIV(PCA) + HOO. + H+. The VIV species thus formed reacts further with a second H2O2 molecule to generate the hydroxyl radical according to the equation VIV(PCA) + H2O2 → VV(PCA) + HO. + HO-. The concentration of the active species in the course of the catalytic process has been estimated to be as low as [V(PCA)H2O2] ≈ 3.3 × 10-6 mol dm-3. The effective rate constant for the cyclohexane oxidation (d[ROOH]/dt = keff[H2O2]0[V]0) is keff = 0.44 dm3 mol-1 s-1 at 40 °C, the effective activation energy is 17 ± 2 kcal mol-1. It is assumed that the accelerating role of PCA is due to its facilitating the proton transfer between the oxo and hydroxy ligands of the vanadium complex on the one hand and molecules of hydrogen peroxide and water on the other hand. For example: (pca)(O=)V ... H2O2 → (pca)(HO-)V-OOH. Such a "robot's arm mechanism" has analogies in enzyme catalysis.

Direct Detection of the Cation Radical of the Spin Trap α-Phenyl-N-tert-butylnitrone

The radical cation PBN 2 of the spin trap α-phenyl-N-tert-butylnitrone (PBN, 1) was observed directly max(H2O)/nm 410 3 mol-1 cm-1 (5+/-1)*103>> and characterised by pulse radiolysis and laser flash photolysis absorption measurements in solvents of different polarity (water, CH3CN, BuCl) as well as by low-temperature EPR.It was generated by direct two-photon ionisation of PBN, by electron-transfer from PBN to solvent cation radicals or to photoexcited triplet chloranil, and by reaction of PBN with the oxidising anion radical SO4.The γ-irradiation of PBN in alkyl halide glasses at 77 K yielded green-coloured samples containing the stabilised radical cation PBN, whose EPR spectrum indicates the presence of aminoxyl-type radicals.PBN cation radical reacts with a variety of nuclophiles to yield the corresponding stable aminoxyl radicals.Based on spectroscopic, kinetic and chemical evidence it is concluded that PBN cation radical is an aminoxyl substituted phenylcarbenium ion.

Mechanistic Studies by Electron Paramagnetic Resonance Spectroscopy on the Formation of 2-(N-Chloroimino)-5,5-dimethylpyrrolidine-1-oxyl Radical from 5,5-Dimethyl-1-pyrroline 1-Oxide and Hypochlorite-Treated Ammonia

Mixtures of ammonium ion (NH4(1+)) or ammonia (NH3), hypochlorous acid (HOCl), and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) gave the radical 2-(N-chloroimino)-5,5-dimethylpyrrolidine-1-oxyl (1).The first step in the formation of 1 was the reaction of HOCl and NH4(1+) to provide ammonia chloramines: monochloramine (NH2Cl), dichloramine (NHCl2), and trichloramine (NCl3).Chloramine composition and the formation of 1 were dependent on pH, the ratio of NH4(1+) to HOCl, and, at acidic pH, on the concentration of chloride in the medium.Conditions were chosen to isolate the individual chloramines in solution for further study.NCl3 and DMPO gave 1; however, NHCl2 and NH2Cl required additional oxidants such as HOCl or PbO2 to produce 1.Studies with 15N-labeled chloramines confirmed that NHCl2 and NH2Cl reacted with DMPO to form N-chloro intermediates that yielded 1 upon subsequent oxidation.Light had no effect on the formation of 1, and UV irradiation did not enhance the EPR signal intensity but caused rapid decay, indicating that radical intermediates of ammonia chloramines were not involved.The mechanism of formation of 1 appeared to involve temporary attachment of chloramine Cl to the nitroxide oxygen of DMPO which activated its β-carbon for nucleophilic addition of the chloramine N.Subsequent N-chlorination and/or dehydrochlorination, depending on the reactive chloramine, would then provide 1.However, nucleophilic addition of H2O to the activated β-carbon of DMPO was competitive because 5,5-dimethyl-2-hydroxypyrrolidine-1-oxyl (DMPO-OH) or 5,5-dimethyl-2-pyrrolidone-1-oxyl (DMPOX) radicals were sometimes observed as minor products along with 1.Analogous chloroimine radicals were not obtained from the reaction of ammonia chloramines with 3,3,4,4-tetramethyl-1-pyrroline 1-oxide (M4PO) and N-tert-butyl-α-phenylnitrone (PBN), although their 2-oxo nitroxyl derivatives and hydroxyl adducts were formed as radical products suggesting that nucleophilic addition of H2O was dominant with these nitroxides.

Decay and fate of the hydroxyl radical adduct of α-Phenyl-n-tert-butylnitrone in aqueous media

The lifetime of α-(hydroxylbenzyl)-tert-butylaminoxyl, the hydroxyl radical adduct of α-phenyl-N-tert-butylnitrone (PBN) produced by spin trapping, is measured with an EPR spectrometer at various pH values in phosphate buffer. The decay of the EPR signal

An electron spin resonance spin trapping investigation of azide oxidation on TiO2 powder suspensions

The oxidation of azide has been studied on TiO2 powder suspensions in water, methanol, and mixtures of the two solvents.The esr spin trapping technique has been employed to provide evidence for the formation of azidyl radicals N.3.The results show that an aqueous alkaline medium is necessary to obtain a high production of N.3 radicals.A mechanism is proposed whereby the oxidation of N-3 is mainly due to reaction with OH. radicals which are in turn generated upon capture of holes by OH- groups adsorbed on TiO2.Azidyl anions adsorb weakly on TiO2 and do not displace adsorbed OH- from the surface.

Reactions of Ozonate and Superoxide Radical Anions

Potassium ozonate has been prepared by reaction of ozone with potassium superoxide dispersed in Freon-12.Orange solutions of potassium ozonate in benzene or toluene containing 18-crown-6 react with nitrone traps to give spin adducts mainly derived from the oxide radical anion, which is a decomposition product of the ozonate radical anion.With 2-methyl-2-nitrosopropane in toluene solution the ozonate gives five nitroxide radicals in whose formation the oxide radical anion is again implicated.With nitrosobenzene electron transfer occurs.Comparable reactions with superoxide are described.

Studies on the Hydroxylation of Phenylalanine by 6,7-Dimethyl-5,6,7,8-tetrahydropteridine

The hydroxylation of phenylalanine by 6,7-dimethyl-5,6,7,8-tetrahydropteridine (DMPH4) was investigated.When phenylalanine was treated with DMPH4 in citrate buffer (pH 6.0), p-tyrosine, m-tyrosine and o-tyrosine were identified as hydroxylated products.The hydroxylation was pH-dependent, and the maximum rate was found at around pH 6.Replacement of air with nitrogen gas and the addition of hydroxyl radical scavengers or catalase prevented the hydroxylation.In contrast, ferrous ions significantly accelerated the hydroxylation as compared with other transition metal ions.In an aqueous solution of DMPH4 under aerobic conditions, the electron spin resonance (ESR) spectra of the hydroxyl radical spin adducts with spin traps such as α-phenyl N-tert-butylnitrone (PBN) and α-4-pyridyl 1-oxide N-tert-butyl nitrone (4-POBN) were observed.The results indicate that the hydroxylating effect of DMPH4 is caused by hydroxyl radicals formed during the autooxidation of DMPH4.Keywords - hydroxylation; phenylalanine; p-tyrosine; m-tyrosine; o-tyrosine; 6,7-dimethyl-5,6,7,8-tetrahydropteridine; ESR; spin-trapping; hydroxyl radical