A new class of bifunctional organocatalysts containing both thiazolidine/pyrrolidine and imidazole cycles was prepared via a readily available synthetic route.
In this work, a one-pot sequential organocatalytic method for the synthesis of fused [1,2,3]triazolo [1,5-a]quinolines through successive cyclization and condensation is presented. In this synthetic strategy, the intermolecular [3 + 2]-cycloaddition occurs between 1,3-dicarbonyl compounds and o-carbonyl-substituted phenylazide compounds, for the formation of the 1,2,3-triazole intermediates. Subsequently, an intramolecular condensation reaction generates the fused quinoline ring by the new CÀ C bond formation, giving the products in yields ranging from moderate to excellent. All the reactions were performed using 20 mol% of 1,8diazabicyclo[5.4.0]undec-7-ene (DBU) as catalyst in the presence of DMSO as solvent at 120°C for 24 h and tolerate a range of 1,3-dicarbonyl compounds, such as β-keto esters and 1,3-diketones, and o-formyl, o-acetyl or o-benzoyl substituted phenylazide compounds.
Resumo: O presente trabalho tem por objetivo analisar as práticas e reflexões de uma estagiária de docência em Química (curso de Licenciatura em Química da Universidade Federal do Rio Grande do Sul), que esteve em atividade de regência em uma instituição escolar pública federal, localizada na região metropolitana de Porto Alegre – RS. A metodologia de aprendizagem baseada em problemas foi utilizada para trabalhar a temática “alimentação saudável” com quatro turmas de cursos técnicos integrados ao Ensino Médio. Foi desenvolvido um estudo qualitativo exploratório, baseado em uma única fonte documental (o relatório de estágio produzido ao final da disciplina), sendo realizada a análise de conteúdo da produção textual citada. Foram obtidas oito categorias de análise emergentes dessa investigação, que deram indicativos de que o estágio propiciou para a professora em formação a constituição de reflexões relevantes a respeito do ofício docente, principalmente no que tange à experimentação de diferentes práticas de ensino-aprendizagem e avaliação, tendo em vista os momentos de construção de conhecimentos protagonizados pelos sujeitos da instituição de ensino onde foi realizado o referido período de regência. A partir dessas categorias, foram construídas algumas asserções de conhecimento, que foram consideradas como desafios a serem transpostos pelos sujeitos e instituições relacionados à área de Educação em Ciências.Palavras-chave: Aprendizagem baseada em problemas. Alimentação saudável. Ensino de Química. Formação docente. PROBLEM-BASED LEARNING INVOLVING THE THEME FEED: REFLECTIONS ARISING FROM A STAGE IN CHEMISTRY TEACHING Abstract: The present work has the objective of analyzing the practices and reflections of a chemistry trainee (Teacher Training Degree in Chemistry of the Federal University of Rio Grande do Sul), who was in a regency activity at a federal public school institution located in the metropolitan region of Porto Alegre – Rio Grande do Sul – Brazil. Problem-based learning methodology was used to work on the theme "healthy feed" with four classes of technical courses integrated to High School. An exploratory qualitative study was developed based on a single documentary source (the stage report produced at the end of the course) and the content analysis of the textual production was performed. Eight categories of analysis emerged from this research which gave indications that the training provided the teacher in the formation of relevant reflections regarding the teaching profession, mainly in relation to the experimentation of different teaching-learning practices and evaluation, taking into account the moments of construction of knowledge carried out by the subjects of the educational institution where the said regency period was held. From these categories some assertions of knowledge were built which were considered as challenges to be transposed by the subjects and institutions related to the area of Science Education.Keywords: Problem-Based Learning. Healthy feed. Chemistry teaching. Teacher Education.
An important contribution to the field of asymmetric catalysis is described in this work, as it merges the search for new ligands that can provide high performance in asymmetric catalysis with the extremely important and increasing need for sustainability. New chiral ionic liquids have been synthesised from the amino acid l‐cysteine by straightforward routes. With these ligands, we have developed a chiral ionic system that includes chiral ionic liquids and their immobilisation in ionic solvents to provide a chiral supramolecular structure. These new catalytic systems were used in the enantioselective addition of alkylzinc to aldehydes and proved to be very efficient, capable of providing chiral secondary alcohols in excellent enantiomeric excesses and yields. This system also enabled the recycling of the ionic media and the ionic ligand, taking into account green chemistry considerations.
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