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Kalinovskaya, I. V.; Карасев, В. Е.; Zadorozhnaya, A. N.; Lifar, L. I.

doi:10.1023/a:1011349918468

Cited by 29 publications

(11 citation statements)

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“…Outros tipos de complexos de alumí-nio(III) 31 , manganês(I) 32 , európio 33,34 e térbio 34 , envolvendo este mesmo ligante, têm sido preparados com diferentes finalidades. O ácido quinolínico pode também ser usado como material de partida na preparação de outras classes de substâncias 35 .…”

Section: Uso Do áCido Quinolínico Como Ligante E Materials De Partidaunclassified

Métodos de preparação e atividade biológica do ácido quinolínico e derivados

Souza¹,

Almeida²,

Hyaric³

et al. 2003

Quím. Nova

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. In 1981 2,3-pyridine dicarboxylic acid (quinolinic acid) was discovery to be a selective agonist for the N-methyl -D-aspartic acid (NMDA) receptor. As a consequence it possesses neurotoxic activity resulting from overstimulation of the receptor. Quinolinic acid is implicated as an etiological factor in a range of neurodegenerative disease including AIDS related dementia, Huntington´s disease and Lyme disease. In the design of novel therapies to treat these diseases, some molecules have been identified as an important target. In this paper we described different methods to prepare quinolinic acid and derivatives.Keywords: quinolinic acid; NMDA receptor; AIDS related dementia. INTRODUÇÃOMais de um terço dos pacientes infectados pelo HIV sofrem de problemas neurológicos. Os sintomas incluem deficiência cognitiva e motora, conhecido como "AIDS dementia complex", mielopatia, neuropatia periférica e disfunções visuais 1 . A proporção de pacientes que sofrem de tais sintomas tende a aumentar à medida que as infecções oportunistas progridem. Segundo a maioria dos especialistas, uma vacina preventiva anti-HIV ou ainda um medicamento ideal é um objetivo a longo prazo e, todavia, incerto, sendo portanto necessário encontrar meios de curar os graves efeitos cognitivos associados à infecção causada pelo HIV. Este artigo aborda um suposto mecanismo da neurotoxicidade ligada ao HIV, assim como méto-dos de preparação do ácido quinolínico e de alguns de seus derivados, visando a prevenção ou a diminuição dos problemas cognitivos e motores provocados pelo HIV. Mecanismo da neurotoxidade associada à infecção pelo HIVOs problemas neurológicos associados ao HIV aparecem mesmo na ausência de infecções oportunistas e não são conseqüências de uma infecção direta dos neurônios pelo HIV 2 . Como se pode constatar a destruição ou danos dos neurônios no decorrer da doença, conclui-se que existe a liberação de um ou mais agente(s) neurotóxico(s) pelas células infectadas. Supõe-se que um destes agentes neurotóxicos seja o ácido quinolínico 6 (Esquema 1). Este composto endogênico, produto da degradação enzimática do triptofano 1, é de concentração particularmente elevada no líquido céfalo-raquidiano de pacientes portadores da AIDS 3 . Além desta evidência, o aumento da taxa de ácido quinolínico resulta em um forte aumento da taxa de cálcio nos neurônios, devido à sua interação direta ou indireta com o receptor ácido-N-metil-Daspártico (NMDA) 4-6 , uma das sub-classes dos receptores do glutamato no cérebro. Receptores do glutamatoO ácido L-glutâmico 7 é o principal neurotransmissor do sistema nervoso central dos mamíferos Entre estes três receptores ionotrópicos do glutamato, o receptor NMDA 8 é o mais estudado. Os receptores do glutamato estão implicados em processos fisiológicos fundamentais, tais como os fenô-menos de plasticidade sináptica e de memória 9 . É também conhecido que os aminoácidos excitadores podem causar efeitos neurotóxicos; estas moléculas provocam uma degenerescência neuronal em razão de uma liberação excessiva de cálcio...

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Section: Uso Do áCido Quinolínico Como Ligante E Materials De Partidaunclassified

Métodos de preparação e atividade biológica do ácido quinolínico e derivados

Souza¹,

Almeida²,

Hyaric³

et al. 2003

Quím. Nova

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“…We should note the anomalous increase in the intensity of the band for the forbidden transition 5 D 0 → 7 F 0 . This suggests significant distortion of the Eu(III) coordination polyhedron, with lowering of the symmetry of the luminescence centers when H 2 O 2 molecules are incorporated into the inner sphere of the complex [7,8].…”

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confidence: 99%

Spectral luminescence properties of Eu(III) complexes with tetracycline antibiotics and hydrogen peroxide

Bel'tyukova¹,

Vityukova²,

Egorova³

2007

J Appl Spectrosc

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We have studied the spectral luminescence properties of mixed-ligand complexes of Eu(III) ions with tetracyclines and hydrogen peroxide. We have established that incorporation of hydrogen peroxide into the inner sphere of these complexes leads to a significant increase (by a factor of 10-25) in the intensity of luminescence of the Eu(III) ions, redistribution of the intensities of the 5 D 0 → 7 F j transitions, in particular to an anomalous increase in the intensity of the band for the forbidden transition 5 D 0 → 7 F 0 .Introduction. We know [1] that antibiotics in the tetracycline series form complex compounds with Eu(III) ions in which, as a result of intramolecular transfer of the excitation energy from the organic ligand molecules to the Eu(III) ion, we observe intense luminescence of the europium ion.Sensitized luminescence of Eu(III) in these compounds has been suggested [2-5] for determination of tetracycline, doxycycline, chlortetracycline, and oxytetracycline.At the same time, only scattered information is available on the spectroscopic properties of these complexes. Accordingly, we have studied the spectral luminescence properties of complexes of Eu(III) ions with tetracycline and its derivatives, and also mixed-ligand complexes with hydrogen peroxide.The Experiment. Analytical grade reagents were used. Standard solutions o? europium and neodymium chlorides (0.1 mol/L) were prepared from the corresponding high-purity oxides. Solutions of tetracycline and its derivatives (1⋅10 -2 mol/L) were prepared by dissolving exactly weighed amounts of the drugs in 75% methanol. A standard solution of hydrogen peroxide (1⋅10 -2 mol/L) was prepared from a 3% aqueous solution, the exact concentration of which was determined titrimetrically. The pH of the solutions were established using a 40% aqueous solution of urotropin.The luminescence spectra of the europium(III) ions were recorded in the 560-650 nm region, λ det = 612, 590, and 580 nm (the transitions 5 D 0 →

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“…The resulting terbium(II) quinolinate exhibits paramagnetic properties.Previously we have studied feasibility of solidphase mechanochemical techniques for synthesis of mixed-ligand compounds of europium(III) and terbium(III) with monocarboxylic acids [1,2]. In [3] we have described the mechanochemical synthesis of terbium quinolinate hydrate Tb 2 [C 5 H 3 N(COO) 2 ] 3 .…”

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confidence: 99%

“…In [3] we have described the mechanochemical synthesis of terbium quinolinate hydrate Tb 2 [C 5 H 3 N(COO) 2 ] 3 . 3H 2 O and mixed-ligand terbium(III) quinolinates [C 5 H 3 N(COO) 2 2! ] with nitrogen-containing neutral ligands Tb 2 [C 5 H 3 N(COO) 2 ] 3 D .…”

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Mechanism of the Mechanochemical Synthesis of Mixed-Ligand Terbium(III) Quinolinates

2005

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Mechanochemical synthesis of terbium quinolinates with nitrogen-containing neutral ligands involves several stages; no self-propagation reaction is observed. The resulting terbium(II) quinolinate exhibits paramagnetic properties.Previously we have studied feasibility of solidphase mechanochemical techniques for synthesis of mixed-ligand compounds of europium(III) and terbium(III) with monocarboxylic acids [1,2]. In [3] we have described the mechanochemical synthesis of terbium quinolinate hydrate Tb 2 [C 5 H 3 N(COO) 2 ] 3 . 3H 2 O and mixed-ligand terbium(III) quinolinates [C 5 H 3 N(COO) 2 2! ] with nitrogen-containing neutral ligands Tb 2 [C 5 H 3 N(COO) 2 ] 3 D . 2H 2 O, where D is 1,10-phenanthroline (Phen) or 2,2`-dipyridyl (Dipy).In the present work we studied the mechanism of the mechanochemical synthesis of previoulsly prepared terbium(III) compounds with the dicarboxylic quinolinic acid by means of X-ray phase analysis, thermal gravimetric analysis, and electron spin resonance (ESR).Mechanochemical treatment in a vibrating mill (1000 rpm) of a mixture of a terbium(III) salt, quinolinic acid, and a nitrogen-containing ligand results, within 132 min, to homogenization of the mixture and formation of a colorless powder.The X-ray patterns of the reaction mixture after 1-min mechanical activation and of the starting reagents before mechanical treatment are identical to each other. The X-ray patterns show the same interplanar spacings and reflection intensities. This finding suggests that 1-min mechanical treatment gives rise to no new fractions and results in grinding and stirring of the starting compounds. On further mechanical treatment (90 s), as seen from the X-ray patterns, reflections of the start-ing crystal phases disappear, the intensities of reflections and interplanar spacings change, and a number of broadened reflections appear. The X-ray patterns of the samples prepared under these conditions are not identical to those of complexes prepared by a traditional procedure in aqueousorganic media. The X-ray diffraction data suggest activation of the reaction mixture of the starting compounds. It is only after 2-min mechanical treatment, that the X-ray pattern contain reflections whose intensities and interplanar spacings correspond to mixedligand terbium(III) compounds and suggest completion of their synthesis (comparison with the X-ray patterns of compounds synthesized by a traditional procedure in aqueous ethanol).After mechanical treatment for 30, 60, and 90 s, the reaction mixture [Tb(NO 3 ) 3 . 6H 2 O + C 5 H 3 N . (CO 2 H) 2 ] was subjected to thermal gravimetric analysis. It was found that mechanical treatment produces a slight exothermal effect at 903100oC, assignable to loss of traces of water, as well as an endothermic effect at 2803310oC, assignable to melting of terbium(III) quinolinate. The lack of new exothermal effects in the mechanochemical process suggests that product formation in the activated reaction mixture occurs not by the expense of the reaction heat. The reaction is not self-...

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Untitled

Cited by 29 publications

References 1 publication

Métodos de preparação e atividade biológica do ácido quinolínico e derivados

Métodos de preparação e atividade biológica do ácido quinolínico e derivados

Spectral luminescence properties of Eu(III) complexes with tetracycline antibiotics and hydrogen peroxide

Mechanism of the Mechanochemical Synthesis of Mixed-Ligand Terbium(III) Quinolinates

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