Homolytic substitutions in indolinone nitroxide radicals—I

Berti, Corrado; Colonna, Martino; Greci, Lucedio; Marchetti, Léonardo

doi:10.1016/0040-4020(77)80464-x

Cited by 25 publications

(9 citation statements)

References 9 publications

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“…1 • was synthesized by Aurich et al in a photochemical way and showed a delocalization of the N−O spin density over the whole aromatic ring system, but was short-lived and could not be isolated. 2 • was synthesized by Greci et al via oxidation of 9,9-Diphenylacridane-10-oxyl, isolated and described as stable . We synthesized these two nitroxides again to study their stability and EPR properties in more detail.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Novel Aromatic Nitroxides as Potential DNA Intercalators. An EPR Spectroscopical and DFT Computational Study

et al. 2003

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The synthesis and electron paramagnetic resonance (EPR) spectroscopic properties of three novel aromatic nitroxides and potential DNA intercalators, the carbazole-based 3,6-dimethylcarbazole-9-oxyl, as well as the acridane-based 9-acridanylidenemalonitrile-10-oxyl and 9-ethylacridanylidenecyanoacetate-10-oxyl, are described. The two acridane-based nitroxides can be isolated and are stable in solution as well as in the solid state for several days. Continuous wave X-band EPR measurements and density functional theory (DFT) calculations demonstrated that the spin density is delocalized over the whole molecule in all three cases. Furthermore, the DFT calculations provided insight into the molecular and electronic structures of these nitroxides and yielded hyperfine coupling constants which are in very good agreement with the experimental data allowing therefore an unambiguous assignment of the hyperfine couplings.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Novel Aromatic Nitroxides as Potential DNA Intercalators. An EPR Spectroscopical and DFT Computational Study

et al. 2003

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“…Removal of the solvent in vacuo and semi-preparative TLC (cyclohexane/ethyl acetate, 8:2) resulted in partial recovery of the starting material (37 mg, 0.156 mmol) and isolation of the reaction products (individual yields are reported in Table 2). Compounds 8a [20] , 9 [21] , 10 [20] , and 11 [22] were identified by comparison of their spectral characteristics with those of authentic samples obtained independently and/or literature data. Very small amounts of the following labile intermediates (see Results and Discussion) could be detected and quickly isolated by TLC; the labile nature of radical intermediates 12a and 13a prevented their further purification by crystallization or by common chromatographic techniques: 1 N), a H-7 2.83 (1 H), a H-4,6 1.00 G (2 H) [31] .…”

Section: Methodsmentioning

confidence: 99%

“…a F ca. 3.9 (3 F) G] with EPR spectral data recorded for analogous 2,2-diphenylindolinone-1-oxyls in which a CF 3 substituent is attached at the aromatic nucleus [22] . Further work is in order to confirm this parallel.…”

Section: Reaction Of Mpio With Dimethyldioxirane and Methyl(trifluoromentioning

confidence: 99%

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On the Reaction of Aminoxyls with Dioxiranes

Dinoi

Curci²,

Carloni

et al. 1998

Eur. J. Org. Chem.

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In the reactions of dimethyldioxirane (1a) and methyl(trifluoromethyl)dioxirane (1b) with 2,2,6,6‐tetramethylpiperidinyl‐1‐oxyl (2) (TEMPO) in acetone, the corresponding methoxyamine 1‐methoxy‐2,2,6,6‐tetramethylpiperidine (5) is produced in ≥98% yield, both in air and under N2, and in the absence or presence of a hydrocarbon (adamantane). Kinetic experiments show that aminoxyl 2 triggers the radical decomposition of the dioxirane, in addition to scavenging methyl radicals derived therefrom. The reactions of an aminoxyl less prone to oxidation, namely 1,2‐dihydro‐2‐methyl‐2‐phenyl‐3H‐indol‐3‐one‐1‐oxyl (4), with dioxiranes 1a and 1b in acetone have also been studied. In these cases, not only is the corresponding methoxyamine 8a produced (yield 12−16%), but quinoneimine‐N‐oxides 10 (yield 12−21%) and 11 (yield 18−19%) are also formed. Furthermore, significant amounts (8−14%) of the amine 9 (the product of deoxygenation of 4) can be isolated. These observations provide useful information concerning the free‐radical mechanism that follows the initial attack by the aminoxyl at the dioxirane.

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“…9 Our research group has focused its attention on a different class of aminoxyls, namely the aromatic indolinonic and quinolinic aminoxyls. 10 Our interest in the antioxidant activity of indolinonic aminoxyls stems from the fact that these compounds were shown in chemical systems to scavenge effectively aroyloxyl, 11 phenoxyl, 12 alkyl, 13,14 aminyl, 15 peroxyl 16 and alkoxyl 14 radicals. Based on this reactivity, studies were undertaken to determine their antioxidant activity toward biologically relevant molecules exposed to free radical-mediated damage.…”

Section: Introductionmentioning

confidence: 99%

Reactivity of 2,2-diphenyl-1,2-dihydro-4-ethoxyquinolin-1-yloxyl towards oxygen- and carbon-centred radicals

Carloni¹,

Damiani²,

Scattolini³

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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Diphenyl-1,2-dihydro-4-ethoxyquinolin-1-yloxyl reacts efficiently with both carbon and oxygen centered (peroxyl, alkoxyl, hydroxyl) radicals leading to products which arise mainly from coupling of radicals with the N-O ؒ function or with the conjugated benzene ring. The reaction with superoxide radical is, however, not very effective, as predicted on the basis of the low reactivity of this radical in typical radical reactions.

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Homolytic substitutions in indolinone nitroxide radicals—I

Cited by 25 publications

References 9 publications

Synthesis of Novel Aromatic Nitroxides as Potential DNA Intercalators. An EPR Spectroscopical and DFT Computational Study

Synthesis of Novel Aromatic Nitroxides as Potential DNA Intercalators. An EPR Spectroscopical and DFT Computational Study

On the Reaction of Aminoxyls with Dioxiranes

Reactivity of 2,2-diphenyl-1,2-dihydro-4-ethoxyquinolin-1-yloxyl towards oxygen- and carbon-centred radicals

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