Derivatives of the thiazolidine-2,4-dione core represent a heterocyclic class with several correlated properties. In this context, the synthesis of structural analogues of these bioactive substances becomes attractive in the field of medicinal chemistry. These analogues act as antimicrobial agents against Gram-positives pathogens. The present work aimed to synthesize 10 different derivatives of 5-arylidene-thiazolidine-2,4-dione, employing urea as the catalyst in a solvent-free reaction medium, with yields that ranged from 45 to 99%. The compounds obtained were submitted to an antimicrobial assay against S. aureus ATCC 29213. Two compounds presented minimum inhibitory concentration of 62.5 and 32.5 μg mL-1 and minimum bactericidal concentration < 500 μg mL-1 , demonstrating their antibacterial potential. Principal component analysis was carried out to discriminate the compounds in active and inactive classes. Four geometric and electronic molecular descriptors were required to completely discriminate the compounds. The selected descriptors can guide us in designing new 5-arylidene-thiazolidine-2,4-dione derivatives with enhanced activity.
Com o objetivo de relacionar os descritores geométricos e eletrônicos dos derivados análogos da rutaercarpina com a atividade biológica contra o câncer do sistema nervoso central (CNS), cálculos de química quântica molecular em nível B3LYP/6-31(d) e análise estatística foram realizados para os 21 derivados análogos da rutaecarpina. Dos 86 descritores moleculares calculados, 5 foram selecionados na construção do modelo de análises de componentes principais (PCA). A componente PC1, a qual responde por 46,11% da variância total dos dados, foi capaz sozinha de discriminar completamente os compostos em duas classes: ativos e inativos. Todos os descritores moleculares selecionados pelo modelo PCA são parâmetros eletrônicos. A análise de agrupamento hierárquico (HCA) foi também aplicada aos descritores selecionados pelo modelo PCA. Baseado nos 5 descritores selecionados é possível sugerir novos derivados ativos da rutaercarpina para serem sintetizados. Além disso, um modelo de mínimos quadrados parciais para análise discriminante (PLS-DA) supervisionado foi construído e aplicado com sucesso na discriminação dos análogos à rutaercarpina, o qual foi validado usando um conjunto independente de compostos.In order to relate the geometric and electronic descriptors of the rutaecarpine analogous to their biological activity against cancer of the central nervous system (CNS), molecular quantum chemical calculations at B3LYP/6-31(d) level and statistical analysis were carried out for 21 rutaecarpine analogous. Out of the 86 molecular descriptors calculated, 5 were selected to build the principal component analysis (PCA) model. The PC1 component that accounts for 46.11% of the total variance of the data was alone able to discriminate completely the compounds into two classes: active and inactive. All molecular descriptors selected by PCA model are electronic parameters. The hierarchical cluster analysis (HCA) was also applied on the selected descriptors. Based on the 5 electronic descriptors selected, it is possible to suggest new compounds to be synthesized with activity against CNS cancer. In addition to that, a supervised partial least squares discriminant analysis (PLS-DA) model was built and successfully applied to discriminate rutaecarpine analogues, being validated through an independent test set and considered robust to overfitting.Keywords: central nervous system cancer, quinazoline-beta-carboline-5-one, B3LYP, rutaecarpine analogous Introduction Brain tumors are rare, but their incidence and mortality rates have been increasing over the past decades in several countries, especially among older people.1-3 Although very little about brain tumors is known, it is believed that genetic factors, hormonal and environmental factors are related to the evolution of this disease. 4,5 The central nervous system (CNS) comprises the brain and spinal cord. Patients who experience personality changes, apathy, early dementia, constant headache or even depression can have a brain tumor. 6,7 Data from the American Cancer Society (ACS) sh...
Some indolo[2,1-b]quinalozine (tryptanthrin) analogues present cytotoxic activity against human breast cancer cells. In this work, chemometric methods were applied in the search for building discriminant models between active and inactive analogues, based on the correlations among their in vitro cytotoxic activities and their electronic and geometric molecular descriptors. From 88 descriptors calculated with density functional theory with the exchange correlation functional B3LYP and the basis set 6-31G* (Gaussian 03), 29 were pre-selected based on their Fisher weights, and finally five descriptors (partial charge on atom 15, bond orders between atoms 12-13, 17-25 and 18-26, and energy difference between frontier molecular orbitals) were selected for principal component analysis. This analysis was able to discriminate 12 inactive from 22 active analogues by using only one principal component, accounting for 49% of the total variance and allowing us to better understand the influence of these electronic descriptors in the cytotoxic activity. In addition, a supervised partial least-squares discriminant model was build and successfully used to discriminate tryptanthrin analogues. The model was validated through an independent test set and considered robust to overfitting.
Problematiza aspectos da política curricular, apresentando um estudo comparado entre duas propostas curriculares para as quatro primeiras séries do ensino fundamental – os Guias de ensino para a escola primária, editados pelo MEC em 1962, e as Propostas curriculares para o ensino de 1º grau, editadas pela Secretaria de Educação do Estado de São Paulo (Seesp), em 1991, elaborados em momentos diferenciados da história da educação brasileira, com o objetivo de orientar a prática docente e melhorar a qualidade do ensino público. Destaca os pressupostos políticos, sociais, epistemológicos e didáticopedagógicos que nortearam as duas propostas, o significado político como estratégia de controle do conhecimento, e assinala as implicações desses dispositivos para a prática pedagógica e a profissionalização docente.
Palavras-chave: currículo; propostas curriculares; material didático; currículo das primeiras séries do ensino fundamental.
Abstract
This text analyses the curriculum policy aspects which were presented in a comparative study between two curriculum proposals for the first four grades of elementary school – The guides to elementary school teaching, edited by Ministry of Education and Culture (MEC) in 1962 and the Curriculum proposals for elementary school teaching, of the Sate of São Paulo (edition 1991) which were elaborated on different moments of the Brazilian education history, aimed at guiding the teaching staff in order to improve the quality of public education. The text highlights the political social and pedagogical principles in which the proposals were based. In addition, it analyses the political significance of the curriculum as well as it puts in evidence the implications of these proposals to pedagogical practices and the professionalization of the teaching staff.
Keywords: curriculum; curriculum proposals; didactic material; curriculum of elementary school.
Nitric oxide (NO) is an important chemical compound involved in many physiological and pathological processes in living organisms. However, nitric oxide is a very reactive radical that needs to be carried through organisms to reach the desired biological target. With the aim of developing new compounds that can be used as biomedical NO carrier agents we carried out a theoretical investigation at B3LYP/6-31+G(d)/LANL2DZ level on the interaction of NO with RuTAP (Ruthenium tetraazaporphyrin) and Ru(L)TAP, where L=Cl-, NH₃, and Pyridine (Py)) and the oxidation state of Ru ranging from +1 to +3. The theoretical calculation results show that the geometric and electronic parameters of the Ru-NO bond are highly dependent on the oxidation state of Ru and of the chemical nature of ligand L at axial position. The results also show clearly that RuTAP and Ru(L)TAP are good potential candidates to be used as NO carriers in living organisms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.