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971.
Alina Secrieru Susy Lopes Maria L. S. Cristiano Rui Fausto 《Molecules (Basel, Switzerland)》2021,26(14)
The prototropic tautomerism in 3(5)-aminopyrazoles was investigated by matrix isolation infrared (IR) spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In consonance with the experimental data, the calculations predict tautomer 3-aminopyrazole (3AP) to be more stable than the 5-aminopyrazole (5AP) tautomer (calculated energy difference: 10.7 kJ mol−1; Gibbs free energy difference: 9.8 kJ mol−1). The obtained matrix isolation IR spectra (in both argon and xenon matrices) were interpreted, and the observed bands were assigned to the tautomeric forms with help of vibrational calculations carried out at both harmonic and anharmonic levels. The matrix-isolated compound (in argon matrix) was then subjected to in situ broadband UV irradiation (λ > 235 nm), and the UV-induced transformations were followed by IR spectroscopy. Phototautomerization of the 3AP tautomer into the 5AP form was observed as the strongly prevalent reaction. 相似文献
972.
Renata Jardim Etchart Raoní S. Rambo Bruno Lopes Abbadi Nathalia Sperotto Christiano Ev Neves Fernanda Fries Silva Maiele Dornelles Lovaine Duarte Fernanda Souza Macchi Marcia Alberton Perell Rogrio Vescia Lourega Cristiano Valim Bizarro Luiz Augusto Basso Pablo Machado 《Molecules (Basel, Switzerland)》2021,26(17)
Tuberculosis has been described as a global health crisis since the 1990s, with an estimated 1.4 million deaths in the last year. Herein, a series of 20 1H-indoles were synthesized and evaluated as in vitro inhibitors of Mycobacterium tuberculosis (Mtb) growth. Furthermore, the top hit compounds were active against multidrug-resistant strains, without cross-resistance with first-line drugs. Exposing HepG2 and Vero cells to the molecules for 72 h showed that one of the evaluated structures was devoid of apparent toxicity. In addition, this 3-phenyl-1H-indole showed no genotoxicity signals. Finally, time-kill and pharmacodynamic model analyses demonstrated that this compound has bactericidal activity at concentrations close to the Minimum Inhibitory Concentration, coupled with a strong time-dependent behavior. To the best of our knowledge, this study describes the activity of 3-phenyl-1H-indole against Mtb for the first time. 相似文献
973.
Gilson Celso Albuquerque Chagas Junior Nelson Rosa Ferreira Eloisa Helena de Aguiar Andrade Lidiane Diniz do Nascimento Francilia Campos de Siqueira Alessandra Santos Lopes 《Molecules (Basel, Switzerland)》2021,26(2)
This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high fermentative capacity: Saccharomyces cerevisiae, Pichia kudriavzevii, the mixture in equal proportions 1:1 of both species, and a control fermentation (with no inoculum application). Three starter cultures of yeasts, previously isolated and identified in cocoa fermentation in the municipality of Tomé-Açu, Pará state, Brazil. The seeds with pulp were removed manually and placed in wooden boxes for the fermentation process that lasted from 6 to 7 days. On the last day of fermentation, the almonds were packaged properly and placed to dry (36 °C), followed by preparation for the analysis of volatile compounds by GC-MS technique. In addition to the control fermentation, a high capacity for the formation of desirable compounds in chocolate by the inoculants with P. kudriavzevii was observed, which was confirmed through multivariate analyses, classifying these almonds with the highest content of aldehydes, esters, ketones and alcohols and low concentration of off-flavours. We conclude that the addition of mixed culture starter can be an excellent alternative for cocoa producers, suggesting obtaining cocoa beans with desirable characteristics for chocolate production, as well as creating a product identity for the producing region. 相似文献
974.
Francesca Begini Renata A. Balaguez Allya Larroza Eric F. Lopes Eder Joo Lenardo Claudio Santi Diego Alves 《Molecules (Basel, Switzerland)》2021,26(8)
In this work, we present a simple way to achieve 4-arylselanyl-1H-1,2,3-triazoles from selenium-containing carbinols in a one-pot strategy. The selenium-containing carbinols were used as starting materials to produce a range of selanyl-triazoles in moderate to good yields, including a quinoline and Zidovudine derivatives. One-pot protocols are crucial to the current concerns about waste production and solvent consumption, avoiding the isolation and purification steps of the reactive terminal selanylalkynes. We could also isolate an interesting and unprecedented by-product with one alkynylselenium moiety connected to the triazole. 相似文献
975.
Leila Gimenes Júlio Csar R. Lopes Silva Roselaine Facanali Leandro Wang Hantao Walter Jos Siqueira Marcia Ortiz Mayo Marques 《Molecules (Basel, Switzerland)》2021,26(8)
Lippia alba (Mill.) N. E. Br. (Verbenaceae) is an aromatic shrub whose essential oils have stood out as a promising source for application in several industrial fields. In this study, the essential oils chemical characterization of eight new L. alba genotypes was performed. The selected materials were collected from the Active Germplasm Bank of the Agronomic Institute and the essential oils were extracted by hydrodistillation. Flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) was employed for chemical characterization and evaluation of possible co-eluted compounds. In addition, the chemical analyses were submitted to multivariate statistical analyses. From this investigation, 73 metabolites were identified in the essential oils of the genotypes, from which α-pinene, β-myrcene, 1,8-cineole, linalool, neral, geranial, and caryophyllene oxide were the most abundant compounds among the accessions. This is the first report disclosing α-pinene in higher amounts in L. alba (19.69%). In addition, sabinene, trans-verbenol, myrtenol, (E)-caryophyllene, α-guaiene, germacrene D, and α-bulnesene were also found in relevant quantities in some of the genotypes, and myrtenal and myrtenol could be well separated through the second dimension. Such results contributed to the understanding of the chemical composition of those new genotypes, being important to drive a future industrial applicability and studies in genetic breeding. 相似文献
976.
977.
Bruno L. do Nascimento‐Dias Davi F. de Oliveira Alessandra S. Machado Olga M.O. Araújo Ricardo T. Lopes Marcelino J. dos Anjos 《X射线光谱测定》2018,47(1):86-91
Martian meteorites are excellent study materials for understanding the present and past of Mars, as they are important historical astrophysical artifacts because they possess information about Martian geological evolution and physical and chemical characteristics. In our case, we analyzed the NWA 6963 Martian meteorite classified as basaltic shergottite because of its chemical structure. A computerized microtomography (μCT) study in the NWA 6963 Martian meteorite provided us with 2D and 3D images that were extremely useful for ascertaining the internal structure of the analyzed sample and gave us the opportunity to find a crumpled material with a very peculiar structural format. In addition, it was possible to observe through the μCT that this encrusted material also has a completely different density of the meteorite. Calcium, strontium, and potassium were detected qualitatively, among others through the technique of X‐ray fluorescence. 相似文献
978.
979.
Rodrigo Moreira da Silva;Jéssica Guastalli Barbieri;Valter Eduardo Murie;Maíra Rosato Silveira Silvério;Rafael Augusto Soldi;Lorena Carneiro Albernaz;Laila Salmen Espindola;Paulo Cézar Vieira;Giuliano Cesar Clososki;Ricardo Vessecchi;Norberto Peporine Lopes; 《Rapid communications in mass spectrometry : RCM》2024,38(12):e9739
4,7-Dichloroquinoline (DCQ) represents a group of synthetic molecules inspired by natural products with important roles in biological and biomedical areas. This work aimed to characterize DCQ and its derivatives by high-resolution electrospray ionization (ESI) mass spectrometry and tandem mass spectrometry (ESI-MS/MS), supported by theoretical calculations. Biological assays were carried out with DCQ and its derivatives to determine LC50 values against Aedes aegypti larvae. 相似文献
980.
This is the fourth article of a series that describes the parametrization of a force field for the molecular simulation of common ionic liquids within the framework of statistical mechanics. The force field was developed in the spirit of the OPLS-AA model and is thus oriented toward the calculation of equilibrium thermodynamic and structural properties in the condensed (liquid) phase. The ions modeled in the present paper are cations of the 1,2,3-trialkylimidazolium and alkoxycarbonyl imidazolium families and alkylsulfate and alkylsulfonate anions. As in previous publications, the force field is built in a stepwise manner that allows, for example, the construction of models for an entire family of cations or anions, with alkyl side chains of different length. Because of the transferability of the present force field, the ions studied here can be combined with those reported in our three previous publications to create a large variety of ionic liquids that can be studied by molecular simulation. The extension of the force field was validated by comparison of simulation results with the corresponding crystal structure and liquid density experimental data. 相似文献