Low Resolution Nmr
Mostrando 1-12 de 47 artigos, teses e dissertações.
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1. New Allyldithiocarbimates: Synthesis, Structure and Antifungal Activity against Phakopsora pachyrhizi and Hemileia vastatrix
Twelve tetraphenylphosphonium allyldithiocarbimates were synthesized and fully characterized by high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), infrared and nuclear magnetic resonance (NMR) spectroscopies. The spectroscopic data indicated that the allyldithiocarbimate anions present Z configuration, as confirmed by X-ray crystallograph
J. Braz. Chem. Soc.. Publicado em: 2020-04
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2. Synthesis and Biological Evaluation of New Eugenol-Derived 1,2,3- Triazoles as Antimyco bacterial Agents
Eugenol has diverse biological properties including antimycobacterial activity, and the triazole ring is an important heterocycle in antimycobacterial compounds. Therefore, this research aimed to synthesize novel eugenol-derived 1,2,3-triazole as antimycobacterial agents with interesting cytotoxic profile and pharmacological assets. Sixteen compounds were ob
J. Braz. Chem. Soc.. Publicado em: 04/07/2019
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3. HR-MAS NMR Allied to Chemometric on Hancornia speciosa Varieties Differentiation
This work describes the potential of chemometric analyses applied to 1H high-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR) data for the chemotaxonomic investigation of Hancornia speciosa (Apocynaceae) varieties. This plant, popularly known as mangaba, has a complex morphological differentiation and thus chemical analyses can be u
J. Braz. Chem. Soc.. Publicado em: 2018-04
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4. Non-Invasive Detection of Adulterated Olive Oil in Full Bottles Using Time-Domain NMR Relaxometry
A fast procedure using time-domain nuclear magnetic resonance (TD-NMR) to detect olive oil adulteration with polyunsaturated vegetable oils in filled bottles is proposed. The 1H transverse relaxation times (T2) of 37 commercial samples were measured using low-field nuclear magnetic resonance (LF-NMR) spectrometer and a unilateral nuclear magnetic resonance (
J. Braz. Chem. Soc.. Publicado em: 2017-02
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5. Microwave Assisted Synthesis of Novel Six-Membered 4-C, 4-O and 4-S Lactams Derivatives: Characterization and in vitro Biological Evaluation of Cytotoxicity and Anticoagulant Activity
A series of six-membered lactam derivatives containing C, O and S atoms in position 4 were synthesized using microwave methodology through coupling reactions. The novel compounds were synthesized following two step reaction to yield fifteen derivatives. The final derivative N-(4-(3-oxotiomorpholin)phenyl) hexanamide was selectively toxic to the HCT-116 cell
J. Braz. Chem. Soc.. Publicado em: 2017-02
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6. Molecular dynamics and formation of domains in block copolymers studied by high and low resolution NMR / Dinâmica molecular e formação de domínios em copolímeros em bloco estudados por RMN de alta e baixa resolução
The main objective of this dissertation is the use of NMR methods to characterize the phase separation and, to some extent, the dynamics of the molecular segments in block copolymers. In the first part, NMR Spin Diffusion methods were explored in order to evaluate their performance as well as the main experimental difficulties. For that, a reference tri-bloc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/04/2012
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7. Supressão das anomalias de fase e batimentos laterais em espectros de RMN 13c obtidos com a sequência de precessão livre no estado estacionário
The Steady-State Free Precession (SSFP) sequence has been widely used in low-field and low-resolution imaging NMR experiments to increase the signal-to-noise ratio (s/n) of the signals. Here, we analyzed the Scrambled Steady State - SSS and Unscrambled Steady State - USS sequences to suppress phase anomalies and sidebands of the 13C NMR spectrum acquired in
Química Nova. Publicado em: 2010
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8. 2-Acylcyclohexane-1,3-diones from Peperomia trineura (Miq.) / 2-Acil-cicloexano-1,3-dionas de Peperomia trineura (Miq.)
The crude extract of whole plant (Peperomia trineura) was subjected to adsorption chromatography on silica gel, preparative thin-layer chromatography (CCDP) and semi-preparative HPLC, resulting in the isolation of five novel polyketides with variable chain lenght or presence of unsaturation in the alkyl chain. The structural elucidation of these compounds wa
Publicado em: 2009
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9. Vegetable oil quality analisys of intact seeds through low resolution NMR / Análise da qualidade de óleos vegetais em sementes intactas por RMN de baixa resolução
O biodiesel vem sendo usado como uma alternativa ao diesel com vantagens ambientais. No entanto, existem duas questões que deverão difcultar a implantação deste combustível no Brasil: a não-sustentabilidade da produtividade desses vegetais, e a baixa qualidade dos óleos vegetais disponíveis, inviabilizando a utilização como combustível. Para atenu
Publicado em: 2009
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10. Study of alkali-silica reaction gel in concrete by high-resolution nuclear magnetic resonance / Estudo da reação álcali-sílica em concretos através de ressonância magnética nuclear de alta resolução
The alkali-silica reaction (ASR) occurs between structurally distorted or disordered silica and aqueous solutions of alkaline hydroxides, as KOH or NaOH. The product of the ASR is an alkali-silicate gel, which may expand upon water absorption. When the ASR occurs in mineral aggregate used in concrete, the process of reaction and expansion cause the decrease
Publicado em: 2009
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11. Avaliação da qualidade de frutas por Ressonância Magnética Nuclear em baixa resolução / Use of low resolution NMR to measure the fruit quality
Avaliou-se o uso da RMN em baixa resolução na análise da qualidade interna de frutas intactas, como banana ouro e uva itália, que são frutas climatéricas, que continuam amadurecendo após a colheita e não-climatéricas, respectivamente. As análises das bananas foram realizadas com a seqüência de pulsos CPMG (Carr-Purcell-Meibom-Gill), que gera um s
Publicado em: 2008
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12. Constituintes bioorgânicos isolados de Annona cacans Warming (Annonaceae) e avaliações de bioatividades / Bioorganic constituents isolated of Annona cacans Warming (Annonaceae) and evaluation of bioactivities.
This work reports the phytochemical investigation of wood and leaves (hexane and ethanol) and fruits (ethyl acetate) of Annona cacans Warming (Annonaceae). The research was carried out with usual chromatographic techniques including High Performance Liquid Chromatography. This investigation led to the isolation and identification of 4-hydroxy-3-5-methoxybenz
Publicado em: 2008