Alkylamines radical-cations

Das S, von Sonntag C (1986) Oxidation of trimethylamine by OH radicals in aqueous solution, as studied by pulse radiolysis, ESR and product analysis. The reactions of the alkylamine radical cation, the aminoalkyl radical and the protonated aminoalkyl radical. Z Naturforsch 41b 505-513 Dixon WT, Norman ROC, Buley AL (1964) Electron spin resonance studies of oxidation. Part II. Aliphatic acids and substituted acids. J Chem Soc 3625-3634 Draper HH, Squires EJ, Mahmoodi H, Wu J, Agarwal S, Hadley M (1993) A comparative evaluation of thiobarbituric acid methods for the determination of malondialdehyde in biological materials. Free Rad Biol Med 15 353-363... 

Janovsky, I. Knolle, W. Naumov, S. Williams, F. EPR Studies of Amine Radical Cations, Part 1 Thermal and Photoinduced Rearrangements of n-Alkylamine Radical Cations to their Distonic Forms in Low-Temperature Freon Matrices. Chem. Eur. J., 2004, 10, 5524-5534. 

Nuclear and side chain substitution in aromatics or substitution of a -hydrogen in alkylamines is — in most cases — best rationalized by postulating radical cations as intermediates. For anodic nuclear substitution of aromatics, especially for acyloxylation, cyanation or bromination a ECnECb3 -mechanism is assumed 37,4 9,50,226,227). jc-oxidation of the aromatic to the radical cation 28, which reacts with a nucleophile Nu, e.g., acetate, cyanide, alkoxide, followed by a second electron transfer and deprotonation (Eq. (98) ) ... 

Carbon-oxygen bond heterolysis is responsible for the observed photolyses of 9-aryl-9-xanthenols ° and llH-benzo[b]fluoren-11-ol. - - Evidence for the formation of the 9-fluorenol radical cation as well as the 9-fluorenyl cation has been obtained from a laser flash photolysis study of 9-fluorenol. 1, l-Di-2-thienylethanol undergoes light-induced dehydration to give i,i-di-2-thienylethylene.Single electron transfer pathways, however, are implicated in the ring cleavage reactions of a,j8-epoxy ketones in the presence of allyltributyltin - or alkylamines. 

There have been several papers dealing with the oxidation reactions of nitrogen and sulfur-based compounds. Hindered amines, such as substituted 2,2,6,6-tetramethylpiperidines, are easily oxidized by electron-transfer reactions to the corresponding cation, by the sulfate radical anion, and by sensitized electron transfer to carbonyl triplets. Radicals derived from tertiary piperidines were observed directly by optical spectroscopy and deprotonated to a-alkylamine radicals. The amine radical cation derived from secondary piperidines deprotonated to give aminyl radicals. In the presence of oxygen, both classes were oxidized to give nitroxyl radicals, but by different proposed mechanisms. Both oxidation and fragmentation pathways have been observed in the photochemical reaction of alkyl phenyl sulfides with tetranitromethane. The oxidation of various A-(arylthio)-4-substituted-2,6-diarylanilines (18) with PbOa yielded, in most cases, persistent radicals that could... 

Reaction of primary and secondary alkylamines with cation radicals has received limited attention. Sioda (23) reported that when DPA reacted with ammonia and some primary alkylamines DPA was formed in half the amount of the DPA " used that is, as if reaction had occurred according to eq. 6. However, the substitution product, if formed, was not sought. The only complete reactions we are aware of are our own with organosulfur cation radicals (7 y 24-26). These react with primary amines to give ] -alkylsulfilimine salts (eq. 14). Reaction with dialkylamines... 

Alkylamines undergo a characteristic a cleavage in the mass spectrometer, similar to the cleavage observed for alcohols (Section 17.11). A C—C bond nearest the nitrogen atom is broken, yielding an alkyl radical and a resonance-stabilized nitrogen-con tai nine cation. 

A potential problem when discussing the pA" of alkylamine cation-radicals is that the deprotonation can occur on both the nitrogen and a carbon, for example,... 

Classical SDAs such as alkylamines or alkylammonium cations, which were mentioned in the second part of this article, do not possess special properties which would make them of interest for the construction of materials. Aromatic molecules, in contrast, can be equipped with many different properties. For example, they can act as chromophores, may possess large hyperpolarizabilities (for NLO applications such as SHG, cf the pNA molecule) or stabilize special electronic structures like radicals. However, aromatic molecules are notoriously poor SDAs. One of the few exceptions is pyridine. The hydrothermal treatment of a pyridine - HF - H2O silica solution at 190°C, for instance, results in the formation of large crystals of dodecasil 3C, a clathrasil with small cages. These crystals, which can grow to millimeter size, are acentric at room temperature and exhibit SHG, although the effect is only weak [37]. 

Little is to be found in the literature on the reaction of cation radicals with alkylamines. Shang and Blount (1974) found that DPA + reacts with triethylamine in an ECE sequence to give the... 

Simple alkylamines react with heterocyclic sulfur-containing cation radicals to form sulfilimines [38] in reaction (144). Until... 

A side reaction that occurs between primary alkylamines and the organosulfur cation radicals is the formation of 12 (particularly 12a, c, d). We do not yet know how this occurs. 

Reaction of the organosulfur cation radicals gives ring-pyridinated products, not -pyridinated (e.g., 16 not 17). We supplied an explanation for this and its difference from the ammonia and alkylamine reactions [and the water reaction (6)]. It is that at some stage of product formation a dication intermediate is required (18). In order for the intermediate to lead to a... 

With ammoifia and primary alkylamines having functional groups such as hydroxy, vinyl, ester, cyano, and acetal groups, photoamination occurred without other side reactions, since the amino group has the stronger nucleophilicity and photoaminadon can be performed under mild conditions. However, the secondary amines whose oxidation potentials are relatively low could not be used because of the occurrence of the electron exchange of the cation radicals of the substrates with the amines. 

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