Orientador: Valdecir Farias Ximenes / Coorientador: Luiz Marcos da Fonseca / Banca: Maria Luiza Zeraik / Banca: Iêda Maria Marinez Paino / Banca: Daniel Rinaldo / Banca: Iracilda Zeppone Carlos / Resumo: Inúmeras patologias têm a sua gênese e/ou progressão relacionadas à produção desregulada de intermediários oxidantes. O complexo multienzimático NADPH oxidase é um dos componentes de maior relevância neste contexto, pois é uma das principais fontes de ânion superóxido no organismo animal. Sendo expresso em inúmeros tecidos, incluindo leucócitos e células do tecido endotelial, o desenvolvimento de inibidores eficientes deste complexo enzimático poderá significar uma nova terapêutica para o tratamento de doenças inflamatórias crônicas. Com objetivo de explorar a relação entre a estrutura molecular, as propriedades químicas e atividades biológicas, utilizamos o éster fenetílico do ácido cafeico (CAPE) como inibidor do complexo enzimático NADPH oxidase e comparamos sua eficácia com o seu precursor ácido cafeico e os derivados, éster fenetílico do ácido cinâmico e o ácido clorogênico, correlacionando-os a respeito a sua hidrofobicidade, propriedades redox e inibição do complexo NADPH oxidase em leucócitos ativados. A hipótese seria de que um aumento da hidrofobicidade provocado pela esterificação do ácido cafeico poderia facilitar o seu acesso à membrana celular e assim alterar seu efeito como possível inibidor de NADPH Oxidase. Os resultados, em ensaios in vitro, mostraram que as alterações na hidrofobicidade não provocaram alterações significativas no potencial de oxidação e potencial antioxidantes dos compostos testados. Quando testados em leucócitos ativados (modelos ex vivo),... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Several diseases have their genesis and / or progression related to unregulated production of oxidants intermediates. The multienzymatic complex NADPH oxidase is one of the most important components in this context because it is a major source of superoxide anion in animal organisms. It is expressed in numerous tissues, including leukocytes and endothelial tissue cells. Developing effective inhibitors of this enzyme complex may indicate a new therapy for the treatment of chronic inflammatory diseases. Several studies have described numerous anti-inflammatory properties attributed to caffeic acid phenethyl ester (CAPE), an active component found in propolis. In order to explore the relationship between the molecular structure, chemical properties and biological activities, we used CAPE to inhibit the enzyme complex NADPH oxidase and compare its efficacy with the its precursor caffeic acid and derivatives, phenethyl ester of cinnamic acid and chlorogenic acid, correlating them with regard to hydrophobicity, redox properties and inhibition of NADPH oxidase complex on activated leukocytes. The hypothesis was that an increase of hydrophobicity caused by the esterification of caffeic acid could facilitate access to cell membranes and thereby alter its effect as a possible inhibitor of NADPH oxidase. The results (in vitro), showed that the changes in hydrophobicity did not provoke significant changes in the oxidation potential and antiradical potency of the tested compounds. But whe... (Complete abstract click electronic access below) / Doutor

The purpose of this investigation has been to make a comparison of the experimental and theoretically calculated electron spin resonance spectra of nitrogen heterocyclic radical ions. Because of the recent nature of the field, and because of recent advances in theoretical aspects, the theory of ESR and of the calculation of spin density distributions is reviewed in some detail in Chapter I. In Chapter III the ESR spectra of methyl substituted pyrazine and pyridine anions prepared by chemical reduction with alkali metals are described. Huckel and McLachlan calculations have been performed using various theoretical models and it has been found that presently used simple theories of spin density distributions give a reasonably good explanation of the ESR spectra of these aromatic radical ions. The modified ESR spectra of the ion-pairs of methyl substituted pyrazine, pyridine, and benzene anions with alkali metal cations are examined in Chapter IV. Factors influencing the stability of the ion-pairs are discussed and the theory of alkali metal hyperfine interaction is considered in some detail. It is found likely that in future work attention will have to be directed at the estimation of the energy of excitation from the anion to the cation. Finally, the ESR spectra of some aromatic heterocyclic N-oxide anions generated electrolytically are examined in Chapter V and the results of Huckel and McLachlan calculations of the spin density distributions in the ions are discussed. Because of the perturbed nature of the molecules agreement with the experimental distributions is found to be not quite as satisfactory as with the pyrazine anions. The mechanism of the nitrogen hyperfine interaction in N-oxide anions is investigated and it is suggested that this interaction is overwhelmingly due to the spin density on the nitrogen itself. This last aspect of the ESR spectra of N-oxide anions awaits more complete experimental confirmation. / Science, Faculty of / Chemistry, Department of / Graduate

A radio-frequency positive-ion source and a fifty-kilovolt linear accelerator were designed and constructed in order to produce sizable quantities of hydrogen, helium, nitrogen, neon, and argon. Plans were then made to equip this ion source with charge-exchange apparatus suitable for charge-exchange cross-sectional measurements. It is the purpose of this paper to present the design of the equipment and to present operational knowledge of the equipment and of ion beams which are producible.

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2016. / Made available in DSpace on 2016-09-20T04:25:13Z (GMT). No. of bitstreams: 1 340706.pdf: 2847985 bytes, checksum: 4310e2ace87de0ad50b1b82517f73eff (MD5) Previous issue date: 2016 / O presente trabalho reporta as reações de desfosforilação dos triésteres dietil 2,4-dinitrofenil fosfato (DEDNPP) e dimetil 4-nitrofenil fosfato (Paraoxon metílico) pela oxima 2-hidróxi-N-fenilacetamida (8), pralidoxima (2-PAM), diacetilmonoxima (DAM) e dimetilglioxima (DMG) em meio aquoso e meio micelar catiônico, utilizando-se o surfactante brometo de cetiltrimetilamônio (CTAB) como agente tensoativo. Um aumento de cerca de 10 milhões de vezes para a desfosforilação do DEDNPP e Paraoxon foi obtido na presença da oxima (8) em meio aquoso, em comparação com a reação dos triésteres somente em água, e seus principais produtos de reação foram identificados por meio de diferentes técnicas. Além disso, as micelas de CTAB facilitam o encontro dos reagentes e promovem um aumento significativo da velocidade de reação, devido principalmente ao seu caráter hidrofóbico em conjunto com o efeito eletrostático entre a interface catiônica micelar e o ânion oximato. As constantes de velocidade e de ligação entre os reagentes e a micela foram determinadas com êxito por meio do modelo da pseudofase e troca iônica, elucidando os conhecimentos dos efeitos hidrofóbicos e eletrostáticos no planejamento de nanoreatores para a efetiva decomposição de compostos organofosforados tóxicos na presença de alfa-nucleófilos, assim como na elaboração de novos antídotos contra a intoxicação por agentes neurotóxicos.<br> / Abstract: The present work reports the dephosphorylation reactions of the triesters diethyl 2,4-dinitrophenyl phosphate (DEDNPP) and dimethyl 4-nitrophenyl phosphate (methyl Paraoxon) by the oxime 2-hydroxyimino-N-phenylacetamide (8), pralidoxime (2-PAM), diacetylmonoxime (DAM), dimethylglyoxime (DMG) in aqueous and cationic micellar media, using cetyltrimethylammonium bromide (CTAB) as a surfactant. A rate enhancement of 10 million-fold in the dephosphorylation of DEDNPP and Paraoxon was obtained in the presence of the oxime (8) in aqueous medium, in comparison to the spontaneous hydrolysis of the triesters, and the key products of the reactions were identified by various techniques. Besides, the micelles of CTAB show to facilitate the encounter of the reactants and promote a significant rate enhancement of the reactions, due to their hydrophobic characters in addition to the electrostatic effect between the cationic surfactant and the anionic oximate. The reactions rate and binding constants of the reactants in the micelle were obtained using the pseudophase and ionic exchange model, enlightening the exploitation of hydrophobic and electrostatic effects in the planning of nanoreactors for the effective decomposition of organophosphates by alpha-nucleophiles, as well as into the development of more generally applicable antidotes for human poisoning by neurotoxic agents.

Single electron transfer (SET) mechanisms are becoming ubiquitous in modern organic chemistry. However, it is often difficult to distinguish SET mechanisms from polar mechanisms. Kinetics, products and product distributions, and response to perturbation in solvent and substituents are often identical between the two mechanisms. Detection techniques such as EPR, CIDNP, and UV absorption can often detect "blind" pathways and thus cannot provide unambiguous evidence regarding the true mechanism of interest. In recent years mechanistic probes have been developed which can test for single electron transfer in the mechanism of interest in a more unambiguous manner, although a given probe is often applicable to a narrower range of reactions. In this work 1,1-dimethyl-5,7-di-t-butylspiro[2.5]octa-4,7-dien-6-one (6) is presented as a new "hypersensitive" probe for single electron transfer to conjugated carbonyl compounds. This new probe functions in a rather unique fashion, allowing interpretation of the mechanism at work on the basis of the regiochemistry of spirocyclic ring opening. This "regiodifferentiation" based probe was studied with a variety of nucleophiles (particularly Grignard reagents) and has been found to be effective in differentiating SET from polar processes, although surprising results indicative of polar pathways in the case of reaction of 6 with Grignard reagents other than methyl Grignard were found. Additional insight into the mechanism of the reaction of Grignard reagents with conjugated ketones is also presented. / Master of Science

No description available.

<p> The relative acidities of some aryl germanes have been measured in liquid ammonia.</p> <p> The NMR spectra of phenyl silane and phenyl germane have been completely analysed and the chemical shifts shown to arise from the presence of an electric dipole in the molecule. The NMR spectrum of phenyl germyl anion was unambiguously assigned and partially analysed. The results are consistent with little delocalization of the negative charge from the Ge onto the ring.</p> <p> The vibrational spectra of the germyl anion have been observed and the geometry of the molecule estimated from a normal coordinate analysis of the data.</p> <p> The Raman spectrum of liquid ammonia-D3 has been measured and two bands in the Raman spectrum of liquid ammonia have been reassigned.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

No description available.

No description available.