883 resultados para Vinyl
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Esta dissertação reporta a síntese de novos derivados de 4-quinolonas com potencial atividade biológica e está dividida em 3 capítulos. No primeiro capítulo é feita uma breve introdução aos compostos do tipo 4quinolona, azepina e indol, focando a nomenclatura, atividade biológica e métodos de síntese mais comuns deste tipo de compostos, e é apresentada a nomenclatura dos compostos sintetizados ao longo deste trabalho. No segundo capítulo são descritas as metodologias desenvolvidas para obtenção dos compostos pretendidos. Foram sintetizados novos derivados de 4-quinolonas via reações de N-metilação seguida de ciclização in situ da (E)-N(2-acetilfenil)-3-(2-nitrofenil)acrilamida, via reações de redução da 1-metil-2-[2(2-nitrofenil)vinil]quinolin-4(1H)-ona e reações de halogenação da 1-metil-2-[2(2-nitrofenil)vinil]quinolin-4(1H)-ona e da 2-[2-(2-aminofenil)vinil]-1metilquinolin-4(1H)-ona. Posteriormente, fizeram-se estudos de reatividade da 1-metil-2-[2-(2-nitrofenil)vinil]quinolin-4(1H)-ona e da 2-[2-(2-aminofenil)vinil]-3bromo-1-metilquinolin-4(1H)-ona. Na reação de redução in situ seguida de ciclização intramolecular da 1-metil-2-[2-(2-nitrofenil)vinil]quinolin-4(1H)-ona obteve-se a 2-(1H-indol-2-il)-1-metilquinolin-4(1H)-ona. Partindo da 2-[2-(2aminofenil)vinil]-3-bromo-1-metilquinolin-4(1H)-ona via reações de BuchwaldHartwig obteve-se a 11-metil-5H-benzo[6,7]azepino[3,2-b]quinolin-6(11H)-ona. Novas N-[2-(2-(3-bromo-1-metil-4-oxo-1,4-di-hidroquinolin-2il)vinil)fenil]alquilamidas foram obtidas via reações de acilação da 2-[2-(2aminofenil)vinil]-3-bromo-1-metilquinolin-4(1H)-ona em piridina seca usando diferentes cloretos de acilo. Numa tentativa de ciclização intramolecular da N[2-(2-(3-bromo-1-metil-4-oxo-1,4-di-hidroquinolin-2-il)vinil)fenil]-hexanamida via reação de Ullmann intramolecular foi obtida a 2-(1-hexanoil-1H-indol-2-il)-1metilquinolin-4(1H)-ona. Após a descrição detalhada das metodologias de síntese são apresentadas as principais conclusões deste trabalho e perspectivas futuras. Por último, no terceiro capítulo, são apresentados os procedimentos experimentais usados para obtenção dos compostos sintetizados e os dados relativos à sua caracterização estrutural, que foi sendo discutida ao longo do segundo capítulo. Os compostos sintetizados foram caracterizados por espetroscopia de ressonância magnética nuclear monodimensional (1H e 13C) e bidimensional (HSQC, HMBC) e por espetrometria de massa e sempre que possível por espetrometria de massa de alta resolução.
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Foram estudados 20 pares de rins decutias (Dasyprocta prymnolopha Wagler, 1831), com o objetivo de descrever os segmentos anátomo-cirúrgicos arteriais. As artérias renais foram injetadas com solução de Vinilite corada, e os rins foram submetidos à corrosão ácida para a obtenção dos moldes vasculares. Observou-se que as artérias renais da cutia, sempre únicas, dividiram-se em artéria setorial ventral e artéria setorial dorsal, caracterizando dois setores renais separados por plano avascular. As artérias setoriais penetraram no hilo renal (100% dos casos). Estes vasos deram origem aos ramos segmentares responsáveis pela irrigação de territórios independentes em cada setor, os segmentos arteriais renais. No rim direito foram observados 3 (60%), 4 (35%) e 5 segmentos (5%) no setor arterial ventral e 3 (30%), 4 (45%), 5 (20%) e 6 (5%) segmentos no setor dorsal e, à esquerda, 2(10%), 3 (55%) e 4 (35%) segmentos no setor ventral e 3 (25%), 4 (50%) e 5 (25%) no dorsal. Com base na distribuição arterial nos rins de cutia, observaram-se setores e segmentos arteriais independentes, sendo possível, desta forma, a realização de setoriectomia e segmentectomia nesta espécie.
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O objetivo deste trabalho foi analisar a distribuição dos vasos arteriais nos testículos em caprinos com diferentes graus de divisão escrotal. A configuração escrotal foi classificada da seguinte forma: Grupo I: constituído por caprinos com escroto único, Grupo II: com escroto separado até a metade do testículo e Grupo III: com separação escrotal estendendo-se além da metade do testículos. As artérias foram injetadas e coradas com solução de acetado de vinil, sendo os orgãos (30 pares) submetidos à corrossão para obtenção dos moldes vasculares. As artérias testiculares emergem da aorta abdominal, com trajeto retilíneo, atravessam o canal inguinal, apresentam-se espiraladas e envolvidas parcialmente pelo plexo pampiniforme. Próximo à extremidade caudada do testículo, dividem-se mais freqüentemente nos ramos cranial e caudal, os quais emitem vasos colaterais, de onde emergem ramos penetrantes. Os testículos dos animais com nível intermediário de divisão escrotal (Grupo II) apresentam menor quantidade destes ramos, sendo os quadrantes mais povoados o ventrolateral e o dorsolateral. Conclui-se que a origem, o trajeto e a distribuição das artérias testiculares não apresentam variações relacionadas ao grau de divisão escrotal em caprinos.
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Porous polymer particles are used in an extraordinarily wide range of advanced and everyday applications, from combinatorial chemistry, solid-phase organic synthesis and polymer-supported reagents, to environmental analyses and the purification of drinking water. The installation and exploitation of functional chemical handles on the particles is often a prerequisite for their successful exploitation, irrespective of the application and the porous nature of the particles. New methodology for the chemical modification of macroreticular polymers is the primary focus of the work presented in this thesis. Porous polymer microspheres decorated with a diverse range of functional groups were synthesised by the post-polymerisation chemical modification of beaded polymers via olefin cross metathesis. The polymer microspheres were prepared by the precipitation polymerisation of divinylbenzene in porogenic (pore-forming) solvents; the olefin cross-metathesis (CM) functionalisation reactions exploited the pendent (polymer-bound) vinyl groups that were not consumed by polymerisation. Olefin CM reactions involving the pendent vinyl groups were performed in dichloromethane using second-generation Grubbs catalyst (Grubbs II), and a wide range of coupling partners used. The results obtained indicate that high quality, porous polymer microspheres synthesised by precipitation polymerisation in near-θ solvents can be functionalised by olefin CM under very mild conditions to install a diverse range of chemical functionalities into a common polydivinylbenzene precursor. Gel-type polymer microspheres were prepared by the precipitation copolymerisation reaction of divinylbenzene and allyl methacrylate in neat acetonitrile. The unreacted pendent vinyl groups that were not consumed by polymerisation were subjected to internal and external olefin metathesis-based hypercrosslinking reactions. Internal hypercrosslinking was carried out by using ring-closing metathesis (RCM) reactions in toluene using Grubbs II catalyst. Under these conditions, hypercrosslinked (HXL) polymers with specific surface areas around 500 m2g-1 were synthesised. External hypercrosslinking was attempted by using CM/RCM in the presence of a multivinyl coupling partner in toluene using second-generation Hoveyda-Grubbs catalyst. The results obtained indicate that no HXL polymers were obtained. However, during the development of this methodology, a new type of polymerisation was discovered with tetraallylorthosilicate as monomer.
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Hydroalumination of thioacetylenes using DIBAL-H and lithium di-(isobutyl)-n-(butyl)-aluminate hydride (Zweifel's reagent), followed by addition of water, furnished exclusively the (Z)- and (E)-vinyl sulfides, respectively. The regio- and stereochemistry of the intermediates generated, (Z)- and (E)-phenylthio vinyl alanates, were determined by capture with iodine, which afforded the corresponding (E)- and (Z)-1-iodo-1-phenylthio-2-organoyl ethenes. Reactions of the (E)-iodo(thio)ketene acetals with n-BuLi followed by addition of hexanal afforded the (Z)-phenylthio allylic alcohol, while the (Z)-iodo(thio)ketene acetals under similar reactions conditions gave the (E)-phenylthio allylic alcohol exclusively.
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Abstract Title of Document: Diversity in Catalytic Reactions of Propargylic Diazoesters Huang Qiu, Doctor of Philosophy, 2016 Directed By: Professor Michael P. Doyle, Department of Chemistry and Biochemistry Propargylic aryldiazoesters, which possess multiple reactive functional groups in a single molecule, were expected to undergo divergent reaction pathways as a function of catalysts. A variety of transition metal complexes including rhodium(II), palladium(II), silver(I), mercury(II), copper(I and II), and cationic gold (I) complexes have been examined to be effective in the catalytic domino reactions of propargylic aryldiazoesters. An unexpected Lewis acid catalyzed pathway was also discovered by using FeCl3 as the catalyst. Under the catalysis of selected gold catalysts, propargylic aryldiazoesters exist in equilibrium with 1-aryl-1,2-dien-1-yl diazoacetate allenes that are rapidly formed at room temperature through 1,3-acyloxy migration. The newly formed allenes further undergo a metal-free rearrangement in which the terminal nitrogen of the diazo functional group adds to the central carbon of the allene initiating a sequence of bond forming reactions resulting in the production of 1,5-dihydro-4H-pyrazol-4-ones in good yields. These 1,5-dihydro-4H-pyrazol-4-ones undergo intramolecular 1,3-acyl migration to form an equilibrium mixture or quantitatively transfer the acyl group to an external nucleophile with formation of 4-hydroxypyrazoles. In the presence of a pyridine-N-oxide, both E- and Z-1,3-dienyl aryldiazoacetates are formed in high combined yields by Au(I)-catalyzed rearrangement of propargyl arylyldiazoacetates at short reaction times. Under thermal reactions the E-isomers form the products from intramolecular [4+2]-cycloaddition with H‡298 = 15.6 kcal/mol and S‡298= -27.3 cal/ (mol•degree). The Z-isomer is inert to [4+2]-cycloaddition under these conditions. The Hammett relationships from aryl-substituted diazo esters ( = +0.89) and aryl-substituted dienes ( = -1.65) are consistent with the dipolar nature of this transformation. An unexpected reaction for the synthesis of seven-membered conjugated 1,4-diketones from propargylic diazoesters with unsaturated imines was disclosed. To undergo this process vinyl gold carbene intermediates generated by 1,2-acyloxy migration of propargylic aryldiazoesters undergo a formal [4+3]-cycloaddition, and the resulting aryldiazoesters tethered dihydroazepines undergo an intricate metal-free process to form observed seven-membered conjugated 1,4-diketones with moderate to high yields.
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As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy
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Sugar esters are substances which possess surfactant, antifungical and bactericidal actions and can be obtained through two renewable sources of raw materials: sugars and vegetable oils. Their excellent biodegradability, allied to lhe fact that they are non toxic, insipid, inodorous, biocompatible, no-ionic, digestible and because they can resist to adverse conditions of temperature, pH and salinity, explain lhe crescent use of these substances in several sections of lhe industry. The objective of this thesis was to synthesize and characterize surfactants and polymers containing sugar branched in their structures, through enzymatic transesterification of vinyl esters and sugars, using alkaline protease from Bacillus subtilis as catalyst, in organic medium (DMF).Three types of sugars were used: L-arabinose, D-glucose and sucrose and two types of vinyl esters: vinyl laurate and vinyl adipate. Aiming to reach high conversions from substrates to products for a possible future large scale industrial production, a serie of variables was optimized, through Design of Experiments (DOE), using Response Surface Methodology (RSM).The investigated variables were: (1) enzyme concentration; (2) molar reason of substrates; (3) water/solvent rale; (4) temperature and (5) time. We obtained six distinct sugar esters: 5-0-lauroyl L-arabinose, 6-0-lauroyl D-glucose, 1'-O-lauroyl sucrose, 5-0-vinyladipoyl L-arabinose, 6-0-vinyladipoyl D-glucose and 1 '-O-vinyladipoyl sucrose, being lhe last three polymerizable. The progress of lhe reaction was monitored by HPLC analysis, through lhe decrease of sugar concentration in comparison to lhe blank. Qualitative analysis by TLC confirmed lhe formation of lhe products. In lhe purification step, two methodologies were adopted: (1) chromatographic column and (2) extraction with hot acetone. The acylation position and lhe chemical structure were determined by 13C-RMN. The polymerization of lhe three vinyl sugar esters was possible, through chemical catalysis, using H2O2 and K2S2O8 as initiators, at 60°C, for 24 hours. IR spectra of lhe monomers and respective polymers were compared revealing lhe disappearance of lhe vinyl group in lhe polymer spectra. The molar weights of lhe polymers were determined by GPC and presented lhe following results: poly (5-0-vinyladipoyl L-arabinose): Mw = 7.2 X 104; PD = 2.48; poly (6-0-vinyladipoyl D-glucose): Mw = 2.7 X 103; PD = 1.75 and poly (1'-O-vinyladipoyl sucrose): Mw = 4.2 X 104; PD = 6.57. The six sugar esters were submitted to superficial tension tests for determination of the critical micelle concentrations (CMC), which varied from 122 to 167 ppm. Finally, a study of applicability of these sugar esters, as lubricants for completion fluids of petroleum wells was' accomplished through comparative analysis of lhe efficiency of these sugar esters, in relation to three commercial lubricants. The products synthesized in this thesis presented equivalent or superior action to lhe tested commercial products
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This master thesis aims at developing a new methodology for thermochemical degradation of dry coconut fiber (dp = 0.25mm) using laboratory rotating cylinder reactor with the goal of producing bio-oil. The biomass was characterized by infrared spectroscopy with Fourier transform FTIR, thermogravimetric analysis TG, with evaluation of activation energy the in non-isothermal regime with heating rates of 5 and 10 °C/min, differential themogravimetric analysis DTG, sweeping electron microscopy SEM, higher heating value - HHV, immediate analysis such as evaluated all the amounts of its main constituents, i.e., lignin, cellulose and hemicelluloses. In the process, it was evaluated: reaction temperature (450, 500 and 550oC), carrier gas flow rate (50 and 100 cm³/min) and spin speed (20 and 25 Hz) to condensate the bio-oil. The feed rate of biomass (540 g/h), the rotation of the rotating cylinder (33.7 rpm) and reaction time (30 33 min) were constant. The phases obtained from the process of pyrolysis of dry coconut fiber were bio-oil, char and the gas phase non-condensed. A macroscopic mass balance was applied based on the weight of each phase to evaluate their yield. The highest yield of 20% was obtained from the following conditions: temperature of 500oC, inert gas flow of 100 cm³/min and spin speed of 20 Hz. In that condition, the yield in char was 24.3%, non-condensable gas phase was 37.6% and losses of approximately 22.6%. The following physicochemical properties: density, viscosity, pH, higher heating value, char content, FTIR and CHN analysis were evaluated. The sample obtained in the best operational condition was subjected to a qualitative chromatographic analysis aiming to know the constituents of the produced bio-oil, which were: phenol followed by sirigol, acetovanilona and vinyl guaiacol. The solid phase (char) was characterized through an immediate analysis (evaluation of moisture, volatiles, ashes and fixed carbon), higher heating value and FTIR. The non-condensing gas phase presented as main constituents CO2, CO and H2. The results were compared to the ones mentioned by the literature.
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Expedient synthetic approaches to the highly functionalized polycyclic alkaloids communesin F and perophoramidine are described using a unified approach featuring a key decarboxylative allylic alkylation to access a crucial and highly congested 3,3-disubstituted oxindole. Described are two distinct, stereoselective alkylations that produce structures in divergent diastereomeric series possessing the critical vicinal all-carbon quaternary centers needed for each synthesis. Synthetic studies toward these challenging core structures have revealed a number of unanticipated modes of reactivity inherent to these complex alkaloid scaffolds. Finally, a previously unknown mild and efficient deprotection protocol for the o-nitrobenzyl group is disclosed – this serendipitous discovery permitted a concise endgame for the formal syntheses of both communesin F and perophoramidine.
In addition, the atroposelective synthesis of PINAP ligands has been accomplished via a palladium-catalyzed C–P coupling process through dynamic kinetic resolution. These catalytic conditions allow access to a wide variety of alkoxy- and benzyloxy-substituted PINAP ligands in high enantiomeric excess.
An efficient and exceptionally mild intramolecular nickel-catalyzed carbon–oxygen bond-forming reaction between vinyl halides and primary, secondary, and tertiary alcohols has been achieved. This operationally simple method allows direct access to cyclic vinyl ethers in high yields in a single step.
Finally, synthetic studies toward polycyclic ineleganolide are described. The entire fragmented carbon framework has been constructed from this work. Highly (Z)-selective olefination was achieved by the method by the Ando group.
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Dissertação (mestrado)—Universidade de Brasília, Instituto de Artes, Programa de Pós-Graduação em Arte, 2016.
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Biodiesel production from waste cooking oil with methanol was carried out in the presence of poly(vinyl alcohol) with sulfonic acid groups (PVA-SO3H) and polystyrene with sulfonic acid groups (PS-SO3H), at 60°C. The PVA-SO3H catalyst showed higher catalytic activity than the PS-SO3H one. In order to optimize the reaction conditions, different parameters were studied. An increase of waste cooking oil conversion into fatty acid methyl esters with the amount of PVA-SO3H was observed. When the transesterification and esterification of WCO was carried out with ethanol over PVA-SO3H, at 60°C, a decrease of biodiesel production was also observed. The WCO conversion into fatty acid ethyl ester increased when the temperature was increased from 60 to 80°C. When different amounts of free fatty acids were added to the reaction mixture, a slight increase on the conversion was observed. The PVASO3H catalyst was reused and recycled with negligible loss in the activity.