A CIDNP study of the decomposition of aryldiazenes

Evanochko, William T.; Shevlin, Philip B.

doi:10.1021/ja00488a027

Cited by 10 publications

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“…To circumvent these problems, using HPLC and GCMS with authentic standards, we investigated the reaction of two related compounds, 2-ethyll-methoxy-2-phenyldiazenium tetrafluoroborate (3) and 3-phenyl-l,2,3-oxadiazolinium triflate (lb),2 with ben-1Conditions: la, 1 mmol, in 4 mL of CH3CN added to PhSH, 1.4 mmol, in 7 mL of sodium phosphate buffer at pH 7.4 (0.05 M); 25 °C; 4 h; mixture extracted into CH2CI2 which was washed with Na2C03 solution prior to GCMS and HPLC analysis. zenethiol under similar conditions.3 Both of these compounds readily oxidize benzenethiol to diphenyl disulfide, and each reaction produces significant yields of benzene along with minor amounts of azobenzene, biphenyl, and diphenyl sulfide, all of which give significant clues to the reaction course (Scheme 3).4 Benzene, azobenzene, and biphenyl are all decomposition products of phenyldiazene (PhN=NH) (14,15), and their presence in our reaction mixture strongly suggests a possible role for an intermediate diazene.…”

Section: Resultsmentioning

confidence: 80%

Thiol Oxidation by 1,2,3-Oxadiazolinium Ions, Presumed Carcinogens

Loeppky

Srinivasan²

1995

Chem. Res. Toxicol.

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3-Alkyl-1,2,3-oxadiazolinium ions 1 have been proposed as reactive intermediates in the activation of (2-hydroxyethyl)nitrosamines. The reaction of 3-methyl-1,2,3-oxadiazolinium tosylate (1a), 2-ethyl-1-methoxy-2-phenyldiazenium tetrafluoroborate (3), and 3-phenyl-1,2,3-oxadiazolinium triflate (1b) with thiols was investigated to determine the behavior of these compounds toward typical "cellular nucleophiles". Each of these substances oxidizes benzenethiol to diphenyl disulfide. The reaction in aqueous buffer at pH 7.4 is rapid. Reaction of 1b with benzenethiol gives, in addition to the disulfide, benzene, biphenyl, azobenzene, diphenyl sulfide, aniline, and glycolaldehyde. Similar products are obtained from 3. Phenyldiazene is postulated as an intermediate in this process, and its generation from phenyldiazoformate in the presence of benzenethiol gives similar products. Diazenes are presumed to arise by proton abstraction from the CH adjacent to N. The kinetics of reaction of 1a with N-acetylcysteine to give the corresponding disulfide show first order dependence on each reactant and base catalysis. The data from these model chemical experiments suggest that 1,2,3-oxadiazolinium ions could react with abundant thiols in cells to lead to either their detoxification or radical processes emanating from diazenes. The occurrence of thiol-oxadiazolinium ion redox transformations could modulate the alkylation chemistry of these substances as well.

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Section: Resultsmentioning

confidence: 80%

Thiol Oxidation by 1,2,3-Oxadiazolinium Ions, Presumed Carcinogens

Loeppky

Srinivasan²

1995

Chem. Res. Toxicol.

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“…36 Aryldiazenes have been generated in situ by the spontaneous hydrolysis and decarboxylation of aryldiazene carboxylate esters 37 and by the reduction of aryldiazonium tetrauoroborates by hydride donors, 26 but their instability has limited diazene characterization to UV-Vis spectroscopy and NMR of disproportionation products. 26,38 Mixed ACN-aqueous solvents allow previously unavailable access to p-NBD and p-CBD diazenes ). 40 The diazonium derivatives were further recrystallized by dissolving a sample (0.5-1.0 g) in a minimum volume of dry acetone and adding a large volume of hexane for crystallization.…”

Section: Resultsmentioning

confidence: 99%

Two-electron redox chemistry ofp-nitro- andp-cyanobenzene diazohydroxides

McEvoy

Pham

et al. 2018

RSC Adv.

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“…1) resulted in slow formation of unpolarized benzene. Slow reactions of diazonium ions do not lead to CIDNP effects (26). This may be attributed to the resulting slow formation of radicals (phenyl) which then react comparatively quickly so that they reside in the solvent cage for shorter periods than required for polarization (27,28).…”

Section: Electron Spin Resonancementioning

confidence: 99%

Sterically hindered aromatic compounds. XI. Spectral and product studies of the decomposition of N-nitrosoacetanilides

Barclay¹,

Dust²

1982

Can. J. Chem.

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DUST. Can. J. Chem. 60,607 (1982). Decomposition of N-nitroso-2,4,6-tri-?err-butylacetanilide (1) in benzene forms products 2,4,6-tri-rert-butylphenyl acetate ( 3 , 3-(3,5-di-tert-butyIphenyl)-2-acetoxy-2-methypropane (4), and hydrocarbons 3-(3,s-di-terr-butylpheny1)-and I-(3,5-di-terr-butylphenyl)-2-methylpropene (5 and 6) explained by a reactive aryl cation (21, the rearranged products (4, 5, 6) originating from a 1,5-hydride shift from an ortho tert-butyl group in 2. In contrast, decomposition of 1 in triethylamine forms products 1,3,5-tri-rerr-butylbenzene (lo), 2,4,6-tri-tert-butylacetanilide (151, and 2-(3,5-di-terr-butylpheny1)-2-methylpropan oxime (13), expected of a free radical pathway. Electron spin resonance evidence is given for intermediates formed by rearrangement of the 2,4,6-tri-tert-butylphenyl radical and spin trapped by the nitroso group of 1. CIDNP and esr studies on the dediazoniation of N-nitrosoacetanilide and aniline in the presence of tertiary amines support the proposed electron transfer mechanism. The results are briefly discussed in terms of the role of steric effects and electron transfer in the dediazoniation of nitrosoacetanilides and diazonium salts.L. Ross C. BARCLAY et JULIAN M. DUST. Can. J. Chem. 60,607 (1982). La decomposition du N-nitroso tri-tert-butyl-2,4,6 acetanilide (1) dans le benzene conduit a la formation de I'acttate de tri-rert-butyl-2,4,6 phenyle (3), de (di-tert-butyl-3,5 phenyl)-3 acetoxy-2 methyl-2 propane (4) et des (di-terr-butyl-3,5 phCny1)-3 et (di-tert-butyl-3,5 ph6nyl)-1 methyl-2 propenes (5 et 6) dont on explique la formation a I'aide d'un cation aryle reactif (2), les produits de transposition ( 4 , s et 6) proviennent d'un deplacement-1,5 d'un hydmre provenant d'un groupement tert-butyle ortho dans 2. Par opposition, la decomposition de 1 dans la triethylamine conduit a la formation de tri-tert-butyl-1,3,5 benzene (lo), de tri-terr-butyl-2,4,6 acetanilide (15) et de l'oxime du (di-tert-butyl-3,5 phenyl)-2 methyl-2 propanal (13) dont la formation est prevue pour un processus radicalaire. Les donnees de la rpe suggerent la presence d'intermediaires formes par une transposition du radical tri-tert-butyl-2,4,6 phenyle qui est piege par le nitroso de 1. Des etudes de CIDNP et rpe sur la dediazotation du N-nitrosoacetanilide et de I'aniline en presence d'amines tertiaires est en accord avec le mecanisme de transfert d'electron propose. On discute brievement des resultats obtenus en termes du r81e des effets steriques et des transferts d'electrons lors de la dediazotation des nitrosoacetanilides et des sels de diazonium.[Traduit par le journal]

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A CIDNP study of the decomposition of aryldiazenes

Cited by 10 publications

References 1 publication

Thiol Oxidation by 1,2,3-Oxadiazolinium Ions, Presumed Carcinogens

Thiol Oxidation by 1,2,3-Oxadiazolinium Ions, Presumed Carcinogens

Two-electron redox chemistry ofp-nitro- andp-cyanobenzene diazohydroxides

Sterically hindered aromatic compounds. XI. Spectral and product studies of the decomposition of N-nitrosoacetanilides

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