Nuclear Magnetic Resonance
Mostrando 1-12 de 1969 artigos, teses e dissertações.
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1. Phenolic Compounds from Leaves of Cariniana estrellensis (Raddi) Kuntze (Lecythidaceae): A Brazilian Atlantic Forest Tree
Cariniana estrellensis (Raddi) Kuntze seedlings have been used in forest restoration programs in the Atlantic Forest biome. However, despite the economic and ecological relevance of this species, to date no general method for rapid identification of primary and secondary metabolites of C. estrellensis leaves has been reported. In this work, we explore the fe
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Synthesis and Evaluation of Antibacterial Activity of 1,2,3-Triazole and Ether Derivatives of Paeonol
Multi-drug-resistant bacteria (MDR) are the cause of different infections and diseases that have affected humanity for a long time, and have been an emerging global health problem that has led to increased morbidity and mortality. The growing emergence of MDR bacteria has underlined the need for development and discovery of new antibacterial compounds. In th
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. NMR Relaxometry Applied to Chemical Studies of Paramagnetic Metal Cation Complexes: Fundamentals and Applications
Low field time-domain nuclear magnetic resonance (TD-NMR) relaxometry of paramagnetic metal cations (PMC) has been widely used to study and improve contrast agents for magnetic resonance imaging (MRI). However, despite its remarkable potential, TD-NMR is rarely used to study PMC complexes, and coordination compounds in non-biomedical application. Therefore,
Journal of the Brazilian Chemical Society. Publicado em: 2022
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4. Two Woody Scented Oils from the Amazonian Forest
The essential oils from Aniba parviflora and the balsam from Protium rubrum, which are two woody scented Amazonian species, were analyzed by gas chromatography-mass spectrometry (GC-MS), 1H and 13C nuclear magnetic resonance (NMR). GC-MS analysis revealed the presence of unknown constituents. These compounds were then isolated, analyzed and characterized by
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. Tailgut Cyst – A Case Report
ABSTRACT Retrorectal hamartoma, also called tailgut cyst, is a congenital lesion resulting from the non-regression of embryo remnants of the hindgut. We describe in this work the case report of a 68-year-old man, previously healthy, complaining of rectal bulging for 4 months, which was diagnosed by nuclear magnetic resonance imaging as a multi-loculated and
Journal of Coloproctology (Rio de Janeiro). Publicado em: 2022
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6. Synthesis of Conjugated Molecules Based on Dithienopyrrole Derivatives and Pyrene as Chemosensor for Mesotrione Detection
The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexyl)-2-(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EP4HP) and 4-(2-ethylhexyl)-2,6-di(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EDP4HP) have been successfully synthesized via C-H direct arylation reaction. The structures of these conjugated molecul
Journal of the Brazilian Chemical Society. Publicado em: 2022
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7. Friedelane Triterpenes with Cytotoxic Activity from the Leaves of Maytenus quadrangulata (Celastraceae)
Three new triterpenes, 3,4-seco-3,11β-epoxyfriedel-4(23)-en-3β-ol (1), friedelan-3α,11β diol (2), 7β,26-epoxyfriedelan-3a,7a-diol (3), a mixture of two new triterpenes 3α-hydroxyfriedelan-29-yl palmitate (4) and 3α-hydroxyfriedelan-29-yl stearate (5) and eleven known compounds were obtained from the hexane extract of Maytenus quadrangulata leaves. The
Journal of the Brazilian Chemical Society. Publicado em: 2022
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8. Synthesis and Biological Evaluation of Novel 1,3-Benzoxathiol-2-one Sulfonamides against Toxic Activities of the Venom of Bothrops jararaca and Bothrops jararacussu Snakes
This work describes the synthesis of new 1,3-benzoxathiol-2-one sulfonamides and evaluation of their ability to inhibit some in vitro (coagulant, proteolytic and hemolytic) and in vivo (hemorrhagic, edematogenic and lethality) toxic activities of Bothrops jararaca and Bothrops jararacussu venoms. Compounds have been synthesized from the coupling of intermedi
Journal of the Brazilian Chemical Society. Publicado em: 2022
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9. Valorization of Hesperidin from Citrus Residues: Evaluation of Microwave-Assisted Synthesis of Hesperidin-Mg Complex and Their Insecticidal Activity
The aim of the current study was the valorization of hesperidin, the dominant flavonoid in citrus processing waste, by microwave-assisted synthesis of hesperidin-Mg complex, improving its antioxidant activity and insecticidal potential. Here we show, for the first time, that microwave-assisted synthesis of [Mg(hesp)2(phen)]OAc (1) (hesp: hesperidin, phen: ph
Journal of the Brazilian Chemical Society. Publicado em: 2022
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10. Synthesis of Eugenol-Fluorinated Triazole Derivatives and Evaluation of Their Fungicidal Activity
Eugenol (C10H12O2, 4-allyl-2-methoxyphenol) is a phenolic natural product that has several biological activities and possibilities of applications. It is herein described the synthesis of eugenol-fluorinated triazole derivatives and evaluation of their fungicidal activity. The reaction of eugenol with epichlorohydrin resulted in the preparation of (±)-2-((4
Journal of the Brazilian Chemical Society. Publicado em: 2022
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11. Anti-Hyperglycemic Activities, Molecular Docking and Structure-Activity Relationships (SARs) Studies of Endiandric Acids and Kingianins from Endiandra kingiana
Diabetes has become a severe chronic disease worldwide with patients significantly increasing daily. Due to the side effects of insulin and oral hypoglycaemic agents employed in diabetes treatment, scientists are working hard to develop alternative approaches from natural plants that inhibit α-amylase and α-glucosidase. Consequently, by performing a phytoc
Journal of the Brazilian Chemical Society. Publicado em: 2022
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12. Absolute Configuration Reassignment of Natural Products: An Overview of the Last Decade
The assignment of absolute configuration (AC) is a crucial step in the structural characterization of natural products, especially for those subjected to biological assays. Methods such as X-ray crystallography, stereocontrolled organic synthesis, nuclear magnetic resonance (NMR), and chiroptical spectroscopies are commonly used to determine the AC of chiral
J. Braz. Chem. Soc.. Publicado em: 2021-08