Benzothiazole hydrazones have been synthesized and evaluated for their in vitro antiproliferative activity against three human cancer cell lines: HL-60 (leukemia), MDAMB-435 (breast) and HCT-8 ...(colon). The good cytotoxicity for the three cancer cell lines and theoretical profile of compounds 3o and 3p pointed them as promising lead molecules for anticancer drug design.
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•Benzothiazole hydrazones were synthesized.•Antiproliferative activity of these compounds was evaluated.•Compounds 3n and 3o showed significant cytotoxicity against leukemia (HL-60).•Compounds 3o and 3p exhibited cytotoxicity against three cancer cell lines.•Benzothiazole hydrazones bear hydroxyl groups may have a good oral biodisponibility.
Com a pandemia da covid-19 e a necessidade de implementação do ensino remoto, diversas estratégias têm sido elaboradas na tentativa de minimizar os danos acarretados ao processo de ...ensino-aprendizagem. Nesse contexto, este trabalho apresenta o desenvolvimento e a implementação de uma metodologia que mostrou resultados positivos na disciplina de Química Geral, ofertada, em modalidade remota, para ingressantes dos cursos de bacharelado em Química Tecnológica e licenciatura em Química, visando aprimorar o processo de ensino-aprendizagem e motivar os alunos para que estudem continuamente. São empregados recursos digitais em uma sequência, que coloca o aluno como protagonista, dando-lhe autonomia sem deixá-lo desassistido. Essa metodologia também pode ser aplicada no ensino presencial como ferramenta de ensino em metodologias ativas, e ser adaptada para diferentes disciplinas, com foco no despertar da curiosidade, do interesse em aprender e, consequentemente, da motivação dos discentes.
Este artigo apresenta um relato de experiência de uma proposta de sequência didática integrada envolvendo as disciplinas de Química Geral e Introdução à Computação, ambas para alunos do primeiro ...semestre de cursos de graduação em Química. As atividades foram planejadas com base em aspectos básicos da Teoria de Aprendizagem Significativa de Ausubel. O uso de análise de dados e a confecção de gráficos em ambientes computacionais, além da aplicação de computação simbólica, mostraram ser ferramentas interessantes no ensino de conceitos de Química. A proposta foi aplicada, e, com isso, observou-se um maior engajamento dos alunos no processo ensino-aprendizagem e um melhor aproveitamento dos estudantes nas avaliações. A sequência didática mostrou ter potencial para aplicação em outras disciplinas de Ciências Exatas do ensino superior.
► Crystal structures of (E)-2-(1,3-benzothiazolyl)-NHNCHAr(Het) are reported. ► Differences in the supramolecular arrangements are observed. ► Calculated conformations are in agreement with ...crystallographic findings.
Structures of hydrazones, (E)-2-(1,3-benzothiazolyl)-NHNCHAr(Ar=pyridine-2-yl (1), pyrrol-2-yl (2), thien-2-yl (3) and furan-2-yl (4), prepared from 2-hydrazinyl-1,3-benzothiazole and ArCHO, followed by recrystallisation from alcohol solutions, are reported. No significant intramolecular hydrogen bonds are present in any of the four molecules. Different conformations were found between 2 and 3, on one hand and for 4, on the other. Thus for 4, the oxygen atom of the furanyl ring is on the same side of the molecule as is the sulfur atom of the benzothiazole unit, while in contrast, each of the heteroatoms of the thienyl and pyrrole rings lies on opposite sides to the benzothiazole sulphur atom. In addition to the conformational variations, differences are noted in the connections between molecules. Despite the presence in each case of N(hydrazono)H---N(benzothiazolo) intermolecular hydrogen bonds, molecules of 4 are linked into spiral chains, while molecules of 2 and 3 (and indeed all compounds having Ar=substituted phenyl) form symmetric dimers. Further intermolecular interactions, albeit weaker ones, are found in 2 CH··N and NH··π, 3 CH··π and 4 π··π, while dimers of 1 remain essentially free. Calculations carried out using the DFT(B3LYP)/6-311++G(d,p) method indicated that the conformations determined by crystallography for 2–4 were the more stable.
•M06-2X/6-311++G(d,p) level calculations on structures and tautomeric stabilities of 2-phenylpyrazolo4,3-cquinolin-3-ones.•X-ray crystallographic study of 2-phenylpyrazolo4,3-cquinolin-3-one ...monohydrates.•Supramolecular arrangements of 2-phenylpyrazolo4,3-cquinolin-3-one monohydrates.
A single crystal X-ray diffraction and theoretical study has been carried out on mono hydrates of three 2H-pyrazolo4,3-cquinolin-3(5H)-one derivatives, namely 6-methyl-2-phenylpyrazolo4,3-cquinolin-3-one, 3, 6-methyl-2-(4-chlorophenyl)pyrazolo4,3-cquinolin-3-one, 4, and 8-methyl-2-(4-nitrophenyl)pyrazolo4,3-cquinolin-3-one, 5. The monohydrates were obtained on recrystallization from moist solvents. While there are three tautomeric forms possible for such pyrazolo4,3-cquinolin-3-one molecules, the sole form isolated in the solid (X)⋅(H2O) (X=3, 4 and 5) compounds was the quinoloid form – the one calculated to be the most stable at the M06-2X/6-311++G(d,p) level of theory. Excellent agreement was found between the calculated and X-ray determined structures. Molecule 5 in (5)⋅(H2O) is very near planar while both molecules 3 and 4 in their respective hydrates are much less so as a consequence of angles about 24° between the two aromatic rings. In each hydrate, the pyrazolo4,3-cquinolin-3-one molecule is bonded to three water molecules and each water molecule is likewise H-bonded to three pyrazolo4,3-cquinolin-3-one molecules. While the water molecules are H-bonded to 3 and 4 via the pyridinyl N and 2x the carbonyl O atoms, in (5)⋅(H2O) the H-bonds are to pyridinyl N, carbonyl O and a nitro O atoms. Calculations indicated that the found arrangement in (5)⋅(H2O) is more stable than one using the connections as found in (3)⋅(H2O) and (4)⋅(H2O). While each of the hydrates possess strong NH⋯O and OH⋯O hydrogen bonds, and weaker CH⋯π and π⋯π interactions, the supramolecular arrays are very different.
The infections caused by the Herpes Simplex Virus are one of the most common sources of diseases in adults and several natural nucleoside analogues are currently used in the treatment of these ...infections.
In vitro tests of a series of quinolonic ribonucleosides derivatives synthesized by part of our group indicated that some of them have antiviral activity against HSV-1.
The conformational analysis of bioactive compounds is extremely important in order to better understand their chemical structures and biological activity. In this work, we have carried out a nuclear relaxation NMR study of 6-Me ribonucleoside derivative in order to determine if the
syn or
anti conformation is preferential. The NMR analysis permits the determination of inter-atomic distances by using techniques which are based on nuclear relaxation and related phenomena. Those techniques are non-selective longitudinal or spin–lattice relaxation rates and NULL pulse sequence, which allow the determination of distances between pairs of hydrogen atoms. The results of NMR studies were compared with those obtained by molecular modeling.
In this work we intend to verify the applicability of a computational methodology to predict structural features of organic compounds with biological activity. We selected three phloroglucinols and ...compared their calculated conformational data with their X-ray crystallographic structure. The results showed that conformations obtained by conformational analysis with the AM1 method followed by geometry optimization by using the DFT B3LYP/6-31 G(d,p) basis set are in very good agreement with X-ray data, indicating that the methodology employed here seems to be a very useful tool in order to predict the conformational preference for this class of compounds.
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