- Synthesis and evaluation of new heteroaryl nitrones with spin trap properties
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A new series of heteroaryl nitrones were synthesized and evaluated as free radical traps due to the results showed in our previous report. The physicochemical characterization of these new nitrones by electron spin resonance (ESR) demonstrated their high capability to trap and stabilize different atom centered free radicals generated by the Fenton reaction. Additionally, we intensely studied them in terms of their physicochemical properties. Kinetic studies, including the use of a method based on competition and the hydroxyl adduct decay, gave the corresponding rate constants and half-lives at the physiological pH of these newly synthesized nitrones. New nitrones derived from quinoxaline 1,4-dioxide heterocycles were more suitable than DMPO to trap hydroxyl free radicals with a half-life longer than two hours. We explain some of the results using computational chemistry through density functional theory (DFT).
- Aliaga, C.,Barriga-González, G.,Cerecetto, H.,Chamorro, E.,González, M.,Norambuena, E.,Olea-Azar, C.,Porcal, W.
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- Quinoxaline-1,4-dioxide fodder suppliments
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The invention relates to new quinoxaline-1,4-derivatives of the general formula (I) and biologically acceptable salts thereof, STR1 wherein Q is a hydrogen atom or a methyl group, R1 represents a hydrogen atom, a cyano, lower alkanoyl or nitro group or a halogen atom, R2 stands for cyano, lower alkanoyl, or a group of the general formula --COOR3, --CONR4 R5 or --CO--NH--NR4 R5, and R3 represents a hydrogen atom or a C1-18 alkyl, C6-12 aryl or C6-10 aryl-(C1-14 alkyl) group optionally substituted by a halogen atom or a hydroxy group, whereby the aromatic ring of the said groups may optionally contain 1-3 identical or different substituents selected from the group consisting of lower alkyl or alkoxy, amino, nitro, halogen and/or hydroxy, R4 is a hydrogen atom or a C1-18 alkyl, a lower alkenyl, a lower alkynyl, a lower cycloalkyl, C6-10 aryl, C6-10 aryl-(C1-4 alkyl) group optionally substituted by a halogen atom or a hydroxy group, whereby the aryl ring of the said groups may optionally contain 1-3 identical or different substituents selected from the group consisting of lower alkoxy, lower alkyl, amino, nitro, halogen and/or hydroxy substituents, a lower alkylcarbonyl, a lower alkylsulfonyl or a C6-10 arylsulfonyl group optionally substituted by an amino or a lower alkyl group; or a mono- or bicyclic heteroarylsulfonyl group, or R4 and R5 represent, together with the adjacent nitrogen atom, a 5 or 6 membered heterocyclic group optionally substituted by a further nitrogen or oxygen atom, with the proviso that if Q represents hydrogen and R2 stands for carboxy, R1 may denote only other than hydrogen. Moreover, the invention relates to a process for the preparation of the above compounds and fodder concentrates, fodder additives or fodders containing the said compounds. The new compounds of the general formula (I) possess weight-gain increasing and antibacterial effects and can be used to advantage in the animal husbandry.
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- Quinoxaline derivatives
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The synthesis of quinoxaline and benzimidazole-N-oxides and of ester and amide derivatives of 3-hydroxy-2-quinoxalinecarboxylic acid by a novel process consisting of the reaction between a benzofuroxan and an activated methylene-containing compound under basic conditions.
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- Decarbonylation of quinoxalines
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Designated 2-formylquinoxaline 1,4-dioxides are decarbonylated by the action of an unhindered secondary amine having a pKa greater than about 8 to produce the corresponding decarbonylated product.
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