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Multicomponent reactions in the discovery of organocatalysts and the diversification of organocatalytic approaches
(Universidade Federal de São Carlos, 2015-06-19) De La Torre, Alexander Fernández; Paixão, Márcio Weber; https://lattes.cnpq.br/3773908504964104; https://lattes.cnpq.br/2494598351529435
This thesis reports the development of multicomponent approaches directed to specific objectives: a) the discovery of new and efficient peptide-based catalyst for asymmetric transformations and b) the synthesis of (hetero)cyclic natural products-like compounds derived from organocatylic/multicomponent reaction sequences. Chapter 1 describes the utilization of the Ugi-4CR reaction for the development of new prolyl pseudo-peptides capable to act as aminocatalysts in asymmetric conjugate addition reactions. Thus, a series of pseudo-peptides having the generic sequences Pro-N-R1-AA-NHR3, being AA an amino acid and R1 and R3 either alkyl or amino acids, were obtained in moderate to excellent yields. The prolyl pseudo-peptides were screened for their catalytic efficacy, most of them proving great efficiency and good to excellent enantio- and diastereoselectivity in the asymmetric conjugate addition of aldehydes to nitroolefins. However, only moderate results were obtained in the asymmetric organocatalytic aldol reaction. A molecular modeling and NMR study were performed for catalysts 67 and 69, aiming to understand their different organocatalytic behavior based on the conformational features. A similar multicomponent process followed by a polymerization step was developed to obtain two new polyfurfuryl alcohol polymers bearing the prolyl pseudo-peptide motif anchored to polymer chain. The prolyl peptide-containing polymers were utilized in the heterogeneous organocatalytic conjugate addition of aldehydes to nitroolefins under bath and flow conditions, producing Michael adducts in moderate yield and enantioselectivity but in excellent diastereoselectivity. Chapter 2 describes the development of new reaction sequences based on consecutive organocatalytic and multicomponent reactions. Several aminocatalytic conjugate addition procedures were implemented to prepare chiral hemiacetals, which were next used in varied Ugi-type multicomponent reactions. These sequences include: a) the Michael addition of nitroethanol to , -unsaturated aldehydes followed by an Ugi reaction leading to cyclic depsipeptide mimics; b) the Michael addition of 1,3-cycloalkanediones to , -unsaturated aldehydes followed by a new stereoselective Ugi-Smiles-type reaction leading to hexahydroquinolin-6-ones; and c) the Michael addition of aldehydes to phenolic nitroolefins followed a new type of multicomponent reaction, leading to pentasubstituted cyclopentenes. The success of these sequences proved the potential of combining organocatalytic asymmetric transformations with follow-up multicomponent reactions for accessing natural product-like cyclic compounds.
Entre imigrantes e nativos digitais : a percepção docente sobre as novas tecnologias da informação e comunicação (NTIC) e o ensino da educação física
(Universidade Federal de São Carlos, 2015-06-19) Indalécio, Anderson Bençal; Campos, Douglas Aparecido de; https://lattes.cnpq.br/7847352503840983; https://lattes.cnpq.br/4024869978826528
This study aimed to understand facts arising from educational processes applied to the teaching of Physical Education at the level of Basic Education, established by agents of different generations and mediated by resources of the new technology. The systematic analysis of the phenomenon permeated the understanding of factors related to the level of perception about the technology object of teachers classified as Immigrants and Digital Natives in the first instance; for later verification of the concerted relationship between the concreteness of the perceptible level expressed by the teacher and the appropriation of technological tools in teaching and learning processes in which they act. Based in a referential qualitative research, the methodology used for the range of explanations about this theme connected the instruments of data collection: structured questionnaire; interviews by guidelines class observations and filmings. The application of research understood two moments, as follows: a diagnostic exploration of the above dimension in the context of the totality of individuals who constitute the population of research, formed by Physical Education teachers effectives in a municipal school system of a municipal district of Northwest Paulista, and therefore, extensive analysis in details of vision and respective practice of teachers of both generational categories, and distinct levels of perception about the New Technologies of Information and Communication, the pedagogical approach mediated by technological resources applied to Physical Education at school. In this context was verified that those involved in the processes of appropriation of technological resources and applied together the learners are influenced to a greater extent by the level of perception maintained by the individual with the technological object, therefore, not justified necessarily the generational dimension of the teacher. This way, the adequation of significant educational proposals with the use of the New Technologies of Information and Communication remits to the perception and respective critically appropriation of technology in personal and professional daily use. In the end, about the interaction processes objectified in constructing of new knowledge, the potential didactic and conceptual gaps resulting from pedagogical actions mediated by technological resources in educational practices observed tend to be minimized by reflective communicative actions, directed to the dialogue between the educator agents, educating and technological object.
Monitoramento de mudas em plantio para restauração ecológica em área de floresta ombrófila densa
(Universidade Federal de São Carlos, 2015-06-19) Vicentin, Alessandra; Leite, Eliana Cardoso; https://lattes.cnpq.br/2186623269243747; https://lattes.cnpq.br/0264017270289536
The Atlantic Forest is considered hotspot for biodiversity conservation, due to its high biological diversity, high endemism and high threat of degradation. This scenario has raised concern about finding information to support recovery projects of degraded areas. This study aimed to evaluate the growth, coverage percentage in the soil and the survival of species of the Atlantic Forest, from the planting seedlings in different treatments, present in a particular area in the recovery process, in the region Vale do Ribeira, located in Sete Barras, Brazil. In 2004, the owner made the removal of vegetation for grazing deployment with brachiaria. In 2009, UFSCar was sought to implement the project of "experimental recovery of degraded areas" where seedlings were planted, divided into spacing of 1.5 x 2 m (dense treatment) and 3 x 2 m (conventional treatment). In this study, from July 2013 was carried out monitoring of the area to assess the growth and survival of planted seedlings as well as the percentage of shading and grasses. Five surveys were conducted (July 2013, October 2013, January 2014, April 2014 and July 2014) to evaluate the survival and growth (height, stem diameter and crown diameter) of the seedlings. 30 months after planting, the 220 individuals initially raised in this study, the survival was 85.2% in the dense treatment and 84.8% in the conventional treatment, so mortality was around 15% for both treatments. The species with the highest average growth in height were Croton floribundus, Cytharexyllum solanaceum, Casearia gossypiosperma, Croton urucurana, Colubrina glandulosa, Lafoensia pacari, Inga marginata e Myrsine guianensis. The species with the highest average growth in stem diameter were Acnistus arborescens, Croton urucurana, Apeiba tibourbou, Croton floribundus, Inga marginata, Campomanesia xanthocarpa, Colubrina glandulosa and Lafoensia pacari. The species with the highest average growth in crown diameter were Croton urucurana, Croton floribundus, Cytharexyllum solanaceum, Acacia polyphyla, Colubrina glandulosa, Inga marginata, Lafoensia pacari and Rhamnidium elaeocarpum. As for the percentage coverage in the soil and grasses, there was significant difference in the dense and conventional treatment compared to witness. It is concluded that the above species are indicated for use in future restoration projects in areas of Rain Forest. Both treatments showed greatest shading (in comparison with witness) at the end of the monitoring period, thereby enabling a reduction of exotic grasses. However, in dense treatment was no shading and greater control of grasses. Thus, it can be concluded that at higher cost of implementation and the similar results, the dense treatment was not recommended thickened in the region.
Propriedades elétricas e estruturais do niobato de potássio e estrôncio obtido pelo método de Pechini
(Universidade Federal de São Carlos, 2015-06-19) Lima, Alan Rogério Ferreira; Camargo, Emerson Rodrigues de; https://lattes.cnpq.br/7720754304065239; https://lattes.cnpq.br/0935068923229080
The search for new technologies more efficient and environmentally sustainable, triggered the search for new materials and synthesis routes that present a low economic and energy impact. In this context, potassium and strontium niobate (KSr2Nb5O15) tetragonal tungsten bronze structure (type-TTB) was doped with La+3 and Ti+4 ions, with the aim of improving the structural and electrical properties and understand the structural effects on the dielectric properties of the structure host. Ceramics with stoichiometry KSr2Nb5O15 and K1+xSr2- 2xLaxNb5O15, K1+4xSr2-1.5xTixNb5-xO15 and K1+2xSr2-2xLaxNb5-xTixO15 (x = 0.05; 0.10 e 0.15) were synthesized using the Pechini method maintaining a molar ratio of citric acid:metal 4:1, mass ratio citric acid:ethylene glycol 60:40. The parameters of time and calcining temperature were optimized in order to obtain powders with high crystal domain crystallographic coherency. The powders were uniaxially and isostatically pressed and sintered in order to obtain dense ceramic bodies for electrical measurements. The ceramic bodies were characterized by morphological, structural and electrical analysis. The presence of La+3 and Ti+4 ions in octahedral led to changes in the network, and morphology of the host structure resulting in different dielectric behavior. The higher dielectric constant value was observed for the host structure KSr2Nb5O15. The dielectric behavior observed for solid solutions K1+xSr2-2xLaxNb5O15, K1+4xSr2-1.5xTixNb5-xO15 and K1+2xSr2-2xLaxNb5-xTixO15 (x = 0.05; 0.10 e 0.15) was attributed to growth abnormal grain in the ceramic body, structural modulations, occupation of octahedral sites and distortions of the octahedral host structure.