http://repositorio.ufgd.edu.br/jspui/handle/prefix/63 Thu, 15 Jan 2026 13:09:17 GMT 2026-01-15T13:09:17Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6258 Título: O piridoxal como precursor de intermediários sintéticos protegidos e halogenados, potenciais blocos de construção de diversidade molecula Autor(es): Daher, Thalita Ocampos Primeiro Orientador: Pizzuti, Lucas Abstract: The reactivity of pyridoxal (PL), pyridoxine (PN) and a furopyridine obtained from pyridoxal against iodination reactions was studied, aiming to obtain vitamin B6 derivatives that can be used as substrates in cross-coupling reactions. The iodination occurred at the C6 carbon of the pyridine ring, and the iodinated derivatives were obtained with yields ranging from 25−73%. The iodinated PL and furopyridine are both novel compounds. In order to obtain precursors of heterocyclic compounds derived from vitamin B6, the work also aimed to obtain chalcones by the Claisen−Schmidt condensation reaction of PL and methylketones. Accordingly, several tests were carried out to protect the PL hydroxymethyl group to prevent the previously reported oxa−Michael addition that would leave to the formation of furopyridines in detriment of chalcones. Attempts to protect the hydroxymethyl group with MsCl, TsCl and Ac2O under several conditions have led to monoprotected and diprotected products in the form of cyclic hemiacetal that are unprecedented in the literature. Reactions involving the hydroxymethyl group of PL with the TMSCl group led to the recovery of part of the substrates used in the reaction and the formation of unidentified products and/or by products. Protection with TBDMSCl from a methodology adapted from the literature, using CH2Cl2 as solvent, imidazole as base, and 3 equivalents of the protection agent led to the selective protection of the hydroxymethyl group in 66% yield. A series of 11 new chalcones was then obtained from the reaction of the protected PL with different ketones. The reaction was carried out in basic medium (NaOH) with EtOH as solvent at room temperature and yields ranged from 53−76%. All compounds were characterized by EMAR, IR and RMN. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação Thu, 15 Apr 2021 00:00:00 GMT http://repositorio.ufgd.edu.br/jspui/handle/prefix/6258 2021-04-15T00:00:00Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6257 Título: Campomanesia adamantium (Cambess.) O.Berg: Variabilidade química e potenciais biológicos Autor(es): Silva, Juliana Ketlin Moro da Primeiro Orientador: Cardoso, Claudia Andrea Lima Abstract: There is an increasing need for alternative products that help treat illnesses. As a result, medicinal plants and their metabolites present themselves as a viable alternative for the treatment and prevention of comorbidities. In this context, Campomanesia adamantium lacks studies that evaluate its potential, since it is a species native to the cerrado, with great economic, cultural and historical value in Mato Grosso do Sul (MS). Therefore, the present study aimed to investigate the chemical composition and antioxidant, photoprotective and anti-inflammatory potential of aqueous extracts of the leaves and stem bark of C. adamantium collected in the municipalities of Campo Grande and Dourados, as well as analyzing the variation in chemical composition and antioxidant and photoprotective potential of C. adamantium leaves in eleven municipalities in MS. Aqueous extracts of leaves and stem bark were prepared by infusion and decoction, respectively. The results obtained indicated that the leaves have a higher content of phenolic compounds and flavonoids compared to the stem barks, as well as higher biological potentials, however, the tannin content in the decoction of the stem barks was higher than that obtained for the infusion of leaves. In the DPPH assay, leafsamples showed antioxidant activity greater than 50%, while aqueous extracts of stem bark showed low inhibition activity (1 to 3.8%). The anti-inflammatory assay demonstrated that the leaves have anti-inflammatory potential. The photoprotective activity performed by the leaves was promising, classifying the respective extracts in the ANVISA category of medium protection, with FPS greater than 14, while the stem barks fall into the low protection category with FPS between 6-8. Regarding the variation in the chemical composition of the leaves in different municipalities, variability was observed in the content of secondary metabolites, resulting in variation in the antioxidant potential that ranged between 11.5-87.2%. Among the municipalities analyzed, the sample collected in the municipality of Cassilândia presented a content of 468.99mg g-1 of phenolic compounds, this being the highest, which resulted in better antioxidant and photoprotective potential. Regarding photoprotective potential, there was no significant difference in SPF between the samples. Therefore, the results of this study are promising for possible applications in multifunctional products with antioxidant and photoprotective properties, in addition to elucidating the importance of investigating the best cultivation region so that it presents the best levels of bioactive compounds andpotential. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação Fri, 15 Mar 2024 00:00:00 GMT http://repositorio.ufgd.edu.br/jspui/handle/prefix/6257 2024-03-15T00:00:00Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6256 Título: Design e aplicação de filmes finos envolvendo crumpled graphene e azul da Prússia Autor(es): Martins, Vitor Hugo Neto Primeiro Orientador: Souza, Victor Hugo Rodrigues de Abstract: This study involves synthesizing thin films through an interfacial method, which relies on composites of Prussian blue nanoparticles and nanostructures derived from graphene, known as crumpled graphene. The resulting compounds underwent evaluation for potential applications in aqueous battery-type energy storage systems. Considering the importance of the relationship between structure/property and application, the processing of carbon nanostructures was previously conducted to assess their morphological characteristics and electrochemical performance as an active material and substrate for the growth of Prussian blue nanocubes. To this end, the spray-pyrolysis method was employed. Observations revealed morphological changes in crumpled graphene when infused with β-FeOOH (β-iron (III) oxyhydroxide) species compared to pure crumpled graphene. Moreover, varying the proportion of iron precursor mass demonstrated a significant influence on material morphology, particularly when comparing ratios of 1:1 and 1:3. In forming the composite between crumpled graphene and Prussian blue utilized the electrodeposition method via cyclic voltammetry, which was proven the formation of Prussian blue nanocubes on the surface of the crumpled graphene with sizes between 48 and 153 nm depending on the number cycles. Specific capacity values varied based on compound structure, with the highest recorded value of 44.4 mAh g-1 for AP_10 composite achieved in an aqueous electrolyte of 0.1 mol L-1 of KCl vs. Ag/AgCl (KCl 3.0 mol L-1). Editor: Universidade Federal da Grande Dourados Tipo: Dissertação Thu, 07 Mar 2024 00:00:00 GMT http://repositorio.ufgd.edu.br/jspui/handle/prefix/6256 2024-03-07T00:00:00Z http://repositorio.ufgd.edu.br/jspui/handle/prefix/6149 Título: Fotocatalisadores do tipo α-Fe2O3/ZnO e α-Fe2O3/CeO2 aplicados na degradação do corante Azul de Metileno Autor(es): Barros, Tayná Silva Bernardino de Primeiro Orientador: Barros, Willyam Róger Padilha Abstract: Advanced oxidation processes (AOPs) have emerged as promising alternative methods for treating wastewater and industrial effluents. Among the AOPs, the photolysis process stands out, which involves the activation of a semiconductor by artificial or sunlight. Thus, the present work developed efficient photocatalysts applied in the Fenton-like degradation process of the Methylene Blue (MB) dye. The degradation study was conducted at pH 3.0; 6.6 and 9.0 using zinc oxide (ZnO) and cerium oxide (CeO2) based catalysts decorated with 2.5%; 5.0%; 10% and 15% hematite (α-Fe2O3). The catalysts were synthesized by the co-precipitation method. All catalysts were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM/FEG), N2(g) physisorption analysis, Fourier transform infrared spectroscopy (FTIR), point of zero charge (pHPZC) and diffuse reflectance spectroscopy (DRS). The degradation experiments were carried out in a single compartment reactor containing a water recirculation system and a controlled temperature of 25 ºC, and the reaction was processed under agitation for 60 min. Samples of MB solution (50 mg L-1) were collected at specific times and subjected to absorbance decay analysis by UV-vis spectrophotometry. Initially, it was found that when the photo-Fenton process was applied, the MB dye removal efficiency was 96.2 and 94.0% when using catalysts with a composition of 5.0% α-Fe2O3/ZnO and 5.0% α-Fe2O3/CeO2, respectively. The high catalytic efficiency of color removal is due to the synergism between Fe3+ ions with Zn2+ or Ce4+ ions, presenting high promotion of photoradical species due to the combination with the Fenton effect. For this experiments, 50 mg of catalyst, 500 µL of H2O2, pH 6.6 and a 250 W Hg lamp (UVA radiation) were used initially. The optimization studies of the degradation parameters showed that there was no significant difference in the MB color removal when varying these parameters. Thus, the optimization parameters chosen were 10 mg of catalyst, pH 6.6, H2O2 volume of 100 µL and MB dye concentration of 10 mg L-1. Real water samples were used as a source of dye contamination, and little interference from the medium was observed, achieving high color removal (~100%). It was also shown that, after the photo-Fenton degradation, the by-products formed during the process did not present high toxicity when in contact with the Lactuca sativa L. specie. The reuse of the 5.0% α-Fe2O3/ZnO and 5.0% α Fe2O3/CeO2, showed high catalytic stability after eight consecutive cycles of degradation when the photo-Fenton process was applied, as well as there was no significant spectral change in the FTIR after the application of the catalysts. Editor: Universidade Federal da Grande Dourados Tipo: Dissertação Fri, 30 Jun 2023 00:00:00 GMT http://repositorio.ufgd.edu.br/jspui/handle/prefix/6149 2023-06-30T00:00:00Z