Oxidative Free Radical Reaction Research Articles

CAN-Mediated Oxidative Free Radical Reactions in an Ionic Liquid

Cerium(IV) ammonium nitrate-mediated oxidative radical reactions are carried out in the presence of ionic liquids, including 1-butyl-3-methylimidazolium tetrafluoroborate, for the first time. The presence of the ionic liquid not only increases the rate and yield of reactions in dichloromethane but also extends the range of 1,3-dicarbonyl precursors, which can be utilized in these carbon–carbon bond-forming reactions.

Cerium Salts in the Oxidative Free‐Radical Reactions Between 2‐Amino‐1,4‐naphthoquinones and β‐Dicarbonyl Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cerium salts in the oxidative free radical reactions between 2-amino-1,4-naphthoquinones and β-dicarbonyl compounds

The oxidative free radical reactions between 2-amino-1,4-naphthoquinones and β-dicarbonyl compounds mediated by cerium(IV) salts are described. In contrast to those mediated by manganese(III) acetate, the cerium(IV) mediated free radical reaction provides a novel method for the synthesis of benzo[ f]indole-4,9-diones exclusively. This high selectivity is due to the strong oxaphilicity of the cerium salts.

ChemInform Abstract: Oxidative Free Radical Reactions Between 2‐Benzyl‐1,4‐naphthoquinones and β‐Dicarbonyl Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Oxidative Free Radical Reactions Between 2‐Amino‐1,4‐naphthoquinones and Carbonyl Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Oxidative free radical reactions between 2-benzyl-1,4-naphthoquinones and β-dicarbonyl compounds

Oxidative free radical reactions between 2-benzyl-1,4-naphthoquinones and β-dicarbonyl compounds are described. Electrophilic carbon-centered radicals produced by the manganese(III) acetate or cerium(IV) ammonium nitrate oxidation of β-dicarbonyl compounds undergo efficient addition to a C–C double bond of quinone ring. This free radical reaction provides a novel method for the synthesis of naphthacene-5,12-diones.

Oxidative free radical reactions between 2-amino-1,4-naphthoquinones and carbonyl compounds

The manganese(III) initiated oxidative free radical reaction provides a novel method for the synthesis of benzo[ f]indole-4,9-diones from 2-amino-1,4-naphthoquinones and carbonyl compounds. The regioselectivity of this reaction was also studied with unsymmetrical ketones from which both isomeric indoles 10 and 11 were formed. With α-halo, α-phenoxy and α-methanesulfonyl ketones, in most cases, this reaction gave high regioselectivity. With 2-alkyl substituted-1,3-dione 14, indole 11 was obtained as the only product.

ChemInform Abstract: A Novel Oxidative Free Radical Reaction Between 2‐Hydroxy‐1,4‐naphthoquinone and β‐Enamino Carbonyl Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A novel oxidative free radical reaction between 2-hydroxy-1,4-naphthoquinone and β-enamino carbonyl compounds

The manganese(III) initiated oxidative free radical reaction between 2-hydroxy-1,4-naphthoquinone and β-enamino carbonyl compound 2 is described. Enamine radical 5 can be generated effectively from the oxidation of enamine 2 by manganese(III) acetate. Spirolactam 3 was prepared effectively from readily available 2-hydroxy-1,4-naphthoquinone and enamine 2 .

Beta-Amyloid protein induces the formation of purine dimers in cellular DNA.

Experimental evidence implicates oxidative free radical reactions as central in the processes of neurodegenerative diseases. In particular, cellular interactions with the beta-amyloid protein have been linked to neuron cell death in Alzheimer's disease. Also, uncharacterized dimeric purine moieties have been detected in oxidized DNAs. It has been suggested that inadequate excision-repair of such products plays a functional role in the neurological degeneration observed in familial Alzheimer's disease, Down's syndrome, and xeroderma pigmentosum. Therefore, in order to obtain a reagent to monitor the presence of such products, the purine dimer 8-8-(2'-deoxyguanosyl)-2'-deoxyguanosine-5'-monophosphate was used as a hapten for elicitation of rabbit anti-purine dimer antiserum. This antiserum specifically recognizes various purified 8-8-bideoxyribonucleosides and 8-8-bideoxyribonucleotides. We found that DNA oxidized by the Fenton reaction is specifically recognized by this antiserum. This reagent can therefore be used to demonstrate formation and excision of DNA purine dimers. Moreover, incubation of cultured rat pheochromocytoma PC-12 cells with the beta-amyloid protein resulted in formation of these purine dimers in cellular DNA. These dimers were subsequently removed from cellular DNA. From these results we conclude that the free radicals generated by A beta cause oxidative DNA alterations including purine dimers. Deficient repair of this type of DNA damage might result in neural cell loss via apoptosis. Our findings suggest mechanisms for the roles of beta-amyloid and oxidative free radicals in neurodegenerative diseases and the role of DNA excision-repair in the prevention of lethal neurotoxicity.

ChemInform Abstract: Manganese(III) Acetate Initiated Oxidative Free Radical Reactions Between 2-Amino-1,4-naphthoquinones and β-Dicarbonyl Compounds.

ChemInform Abstract: Manganese(III) Acetate Initiated Oxidative Free Radical Reactions Between 2-Amino-1,4-naphthoquinones and β-Dicarbonyl Compounds.

Manganese(III) acetate initiated oxidative free radical reactions between 2-amino-1,4-naphthoquinones and beta-dicarbonyl compounds

Manganese(III) acetate initiated oxidative free radical reactions between 2-amino-1,4-naphthoquinones and beta-dicarbonyl compounds

Manganese(III) acetate initiated oxidative free radical reaction between 1,4-naphthoquinones and ethyl nitroacetate

The manganese(III) initiated oxidative free radical reaction between 1,4-naphthoquinones and ethyl nitroacetate is described. Nitromethyl radical 1 can be generated effectively from the oxidation of ethyl nitroacetate by manganese(III) acetate. Naphtho[2,3- d]isoxazole-4,9-diones, benzo[ f]indole-4,9-diones and benzo[ b]acridine-6,11-diones were prepared effectively from readily available 1,4-naphthoquinones and ethyl nitroacetate.

Manganese(III) Acetate Initiated Oxidative Free Radical Reaction between 2-Aryloxy-1,4-naphthoquinones and Dialkyl Malonates

Manganese(III) Acetate Initiated Oxidative Free Radical Reaction between 2-Aryloxy-1,4-naphthoquinones and Dialkyl Malonates

ChemInform Abstract: Manganese(III) Acetate Initiated Oxidative Free Radical Reaction Between 1,4‐Naphthoquinones and α‐Alkylmalonates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Lipid peroxidation and antioxidant system in children living in the Northern Transbaikal region

Exposure to extreme environmental factors of the North creates prerequisites for hyperactivation of free-radical oxidation reactions which may limit the adaptive potential of cells and organism.

Manganese(III) acetate initiated oxidative free radical reaction between 1,4-naphthoquinones and α-alkylmalonates

The manganese(III) initiated oxidative free radical reaction between 1,4-naphthoquinones and α-alkylmalonates is described. Benzo[a]anthraquinones, benzo[f]indole-4,9-diones and naphtho[2,3-b] furan-4,9-diones can be prepared effectively from readily available 1,4-naphthoquinones and α-alkylmalonates.

‘Oxo-hydroxo tautomerism’ as useful mechanistic tool in oxygenation reactions catalysed by water-soluble metalloporphyrins

High valent metal–oxo species have been evoked as active intermediates in many different oxidation reactions using manganese or iron porphyrin complexes as catalysts and oxygen atom donors (H2O2, PhIO, NaOCl, KHSO5, ... etc.) or dioxygen associated to a reductant as oxygen atom source. When these metalloporphyrin-catalysed oxidations are performed in water, such metal–oxo species are able to transfer an oxygen atom coming from either the oxygen source or from bulk water. This fact has been explained by the so-called oxo–hydroxo tautomerism, a mechanism involving a rapid shift of two electrons and one proton from a hydroxo ligand (electron-rich ligand formed by deprotonation of an aqua ligand) to the trans oxo species (electron-poor ligand) leading to the transformation of the hydroxo ligand into an electrophilic oxo entity on the opposite side of the initial oxo. This ‘oxo–hydroxo tautomerism’, evidenced by using 18O-labelled water, has been used as mechanistic tool to unambiguously characterize oxygen atom transfer mechanisms mediated by metal–oxo species in opposition to mechanisms related to free radical oxidation reactions.

ChemInform Abstract: Manganese(III) Acetate Initiated Oxidative Free Radical Reaction Between Benzoylindoles and Dimethyl Malonate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Lipid peroxidation in plasma of patients with osteogenic sarcoma

The intensity of free-radical oxidation reactions assessed by the thiobarbituric acid test and by recording the “fast flash” of Fe2+-induced chemiluminescence is higher in patients with osteogenic sarcoma than in normal subjects. This effect is not sex-dependent and does not depend on previous therapy with drugs triggering free-radical reactions.