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961.
A pharmacophore model for inhibitors of Escherichia coli’s DNA Gyrase B was developed, using computer-aided drug design. Subsequently, docking studies showed that 2,5(6)-substituted benzimidazole derivatives are promising molecules, as they possess key hydrogen bond donor/acceptor groups for an efficient interaction with this bacterial target. Furthermore, 5(6)-bromo-2-(2-nitrophenyl)-1H-benzimidazole, selected as a core molecule, was prepared on a multi-gram scale through condensation of 4-bromo-1,2-diaminobenzene with 2-nitrobenzaldehyde using a sustainable approach. The challenging functionalization of the 5(6)-position was carried out via palladium-catalyzed Suzuki–Miyaura and Buchwald-Hartwig amination cross-coupling reactions between N-protected-5-bromo-2-nitrophenyl-benzimidazole and aryl boronic acids or sulfonylanilines, with yields up to 81%. The final designed molecules (2-(aminophen-2-yl)-5(6)-substituted-1H-benzimidazoles), which encompass the appropriate functional groups in the 5(6)-position according to the pharmacophore model, were obtained in yields up to 91% after acid-mediated N-boc deprotection followed by Pd-catalyzed hydrogenation. These groups are predicted to favor interactions with DNA gyrase B residues Asn46, Asp73, and Asp173, aiming to promote an inhibitory effect. 相似文献
962.
Letícia Coli Louvisse de Abreu Bárbara de Azevedo Abrahim-Vieira Alessandra Mendonça Teles de Souza Eduardo Costa Pinto Mariana da Silva Gonçalves Alice Simon Gil Mendes Viana Carlos Rangel Rodrigues Valeria Pereira de Sousa Lucio Mendes Cabral 《Biomedical chromatography : BMC》2020,34(7):e4832
Injectable solutions containing epinephrine (EPI) and norepinephrine (NE) are not stable, and their degradation is favored mainly by the oxidation of catechol moiety. As studies of these drugs under forced degradation conditions are scarce, herein, we report the identification of their degradation products (DP) in anesthetic formulations by the development of stability-indicating HPLC method. Finally, the risk assessment of the major degradation products was evaluated using in silico toxicity approach. HPLC method was developed to obtain a higher selectivity allowing adequate elution for both drugs and their DPs. The optimized conditions were developed using a C18 HPLC column, sodium 1-octanesulfonate, and methanol (80:20, v/v) as mobile phase, with a flow rate of 1.5 mL/min, UV detection at 199 nm. The analysis of standard solutions with these modifications resulted in greater retention time for EPI and NE, which allow the separation of these drugs from their respective DPs. Then, five DPs were identified and analyzed by in silico studies. Most of the DPs showed important alerts as hepatotoxicity and mutagenicity. To the best of our acknowledgment, this is the first report of a stability-indicating HPLC method that can be used with formulations containing catecholamines. 相似文献
963.
964.
Dr. Paula Munín-Cruz Francisco Reigosa Marcos Rúa-Sueiro Dr. Juan M. Ortigueira Prof. M. Teresa Pereira Prof. José M. Vila 《ChemistryOpen》2020,9(11):1190-1194
A theoretical and experimental study of tetradentate [C,N : C,N] iminophosphorane palladacycles was carried out for the purpose of elucidating their behavior as compared to the parent Schiff base analogues to determine the prospect of encountering new A-frame structures for the iminophosphorane derivatives. The DFT calculations were in agreement with the experimental results regarding the performance of these ligands. New insights into the chemistry of the related dinuclear species have been obtained. 相似文献
965.
Dr. Joana T. Coutinho Dr. Mauro Perfetti Dr. José J. Baldoví Dr. Maria A. Antunes Philipp P. Hallmen Heiko Bamberger Dr. Iris Crassee Dr. Milan Orlita Prof. Manuel Almeida Prof. Joris van Slageren Dr. Laura C. J. Pereira 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(7):1758-1766
Early actinide ions have large spin-orbit couplings and crystal field interactions, leading to large anisotropies. The success in using actinides as single-molecule magnets has so far been modest, underlining the need for rational strategies. Indeed, the electronic structure of actinide single-molecule magnets and its relation to their magnetic properties remains largely unexplored. A uranium(III) single-molecule magnet, [UIII{SiMe2NPh}3-tacn)(OPPh3)] (tacn=1,4,7-triazacyclononane), has been investigated by means of a combination of magnetic, spectroscopic and theoretical methods to elucidate the origin of its static and dynamic magnetic properties. 相似文献
966.
967.
Stéphanie Andrade Dr. Joana Angélica Loureiro Prof. Maria Carmo Pereira 《Chemphyschem》2021,22(15):1547-1565
The aggregation and deposition of amyloid β (Aβ) peptide onto neuronal cells, with consequent cellular membrane perturbation, are central to the pathogenesis of Alzheimer's disease (AD). Substantial evidence reveals that biological membranes play a key role in this process. Thus, elucidating the mechanisms by which Aβ interacts with biomembranes and becomes neurotoxic is fundamental to developing effective therapies for this devastating progressive disease. However, the structural basis behind such interactions is not fully understood, largely due to the complexity of natural membranes. In this context, lipid biomembrane models provide a simplified way to mimic the characteristics and composition of membranes. Aβ-biomembrane interactions have been extensively investigated applying artificial membrane models to elucidate the molecular mechanisms underlying the AD pathogenesis. This review summarizes the latest findings on this field using liposomes as biomembrane model, as they are considered the most promising 3D model. The current challenges and future directions are discussed. 相似文献
968.
969.
P. E. S. De Oliveira L. M. Conserva C. A. De Simone M. A. Pereira V. R. S. Malta D. O. Imbroisi 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o900-o902
X‐ray diffraction studies carried out on single crystals of the monomeric, viz. 5,6‐dimethoxy‐2H‐furo[2,3‐h][1]benzopyran‐2‐one, C13H10O5, and dimeric, viz. 5,5′,6,6′‐tetramethoxy‐3,3′,4,4′‐tetrahydro‐2H,2′H‐3,3′:4,4′‐bi(furo[2,3‐h][1]benzopyran)‐2,2′‐dione, C26H20O10, forms of pimpinellin have revealed that, following cyclodimerization, the carbonyl groups are head‐to‐head with respect to one another. In the monomer, the heterocyclic ring is planar, but it exhibits a twisted‐boat conformation in the dimer. Both the monomer and the dimer interact through C—H⋯O interactions. 相似文献
970.
Danieli Cátia Ceni Laura Alegria Martins Andréa Garcia Pereira Pedro Eduardo Fr?ehlich Ana Maria Bergold 《Chromatographia》2009,69(Z2):189-194
A reversed-phase ion-pairing liquid chromatographic method was developed and validated for the assay of Fe(II) in ferrous
bisglycinate (Fe-bis-gly) capsules using 4-(2-pyridylazo) resorcinol reagent. The analysis was carried out using a Gemini
RP-18 (150 mm × 4.6 mm I.D., particle size 5 μm) analytical column; the mobile phase consisted of a mixture of acetonitrile–water
(28:72 v/v) containing 1 mM tetrabutylammonium hydrogensulfate and 1% phosphate buffer (pH 8.0). The flow rate was 1.0 mL min−1 and the detection was achieved with a photodiode array (PDA) detector at 706 nm. The specificity of the method was proved
using stress conditions and evaluated using a PDA detector. The data validation showed that the method is specific, fast,
accurate, and reproducible for the determination of Fe-bis-gly in dosage form. The response was linear over a range of 1.0–2.6 μg mL−1 (r = 0.9999). The accuracy of the method ranged from 98.02 to 102.75%. The RSD values for intra- and inter-day precision studies
were below 1.3 and 1.1%, respectively. There was no interference of the excipients on the determination of the active pharmaceutical
ingredient. 相似文献