13c Nmr
Mostrando 13-24 de 837 artigos, teses e dissertações.
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13. Blue Glow Sticks: Cinnamic Acids and Arylacrylonitriles with Liquid-Crystalline Properties and Highly Fluorescent
Five new π-conjugated chromophores derived from acrylic acid and acrylonitrile were synthesized and their thermal and photophysical behaviors were analyzed. They were designed and synthesized through Knoevenagel condensations between arylacetylenebenzaldehydes and a methylene group activated from cyanoacetic and malonic acids. The characterization of the ta
J. Braz. Chem. Soc.. Publicado em: 2021-01
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14. Synthesis and Antioxidant and Antimicrobial Properties of β-Hydroxy Sulfides, Sulfoxides, and Sulfones Derived from Cardanol and Glycerol Derivatives
Natural and synthetic sulfur-bearing organic compounds have many applications in medicinal chemistry. This article reports the preparation of amphiphilic β-hydroxy sulfides, sulfoxides, and sulfones derived from cardanol and glycerol. Thiolysis of cardanol epoxide 3 with various thiols (4a-4j) in ethanol or water yielded the corresponding β-hydroxy sulfide
J. Braz. Chem. Soc.. Publicado em: 2020-12
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15. Synthesis, in silico Study and Antimicrobial Activity of New Piperine Derivatives Containing Substituted δ-Esters
A series of fifteen new piperine-derived diesters was synthesized through the substitution reaction between the salt of piperic acid, obtained through piperine basic hydrolysis, with the δ-chloro-esters, obtained through the cleavage of tetrahydrofuran (THF) with acyl chlorides in the presence of ZnCl2. The final compounds were obtained with yields ranging
J. Braz. Chem. Soc.. Publicado em: 2020-12
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16. A Calix[4]arene-Functionalized Perylene Imide and Its Luminescence Properties
In this study, new perylene-derived molecules were synthesized as perylene-3,4,9,10-tetracarboxylic acid monoanhydride monopotassium carboxylate 1; N-(3-propanol)perylene-3,4,9,10-tetracarboxylic-3,4-(monoimide)anhydride-9,10-acid potassium carboxylate 2; 5,11,17,23-tetra(tert-butyl)-25,27-bis(3’-bromopropoxy)-26,28-(dihydroxy)calix[4]arene 3; 5,11,17,23-t
J. Braz. Chem. Soc.. Publicado em: 2020-11
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17. Absolute Configuration of (−)-Cubebin, a Classical Lignan with Pharmacological Potential, Defined by Means of Chiroptical Spectroscopy
This work describes the first determination of the absolute configuration (AC) of (−)-cubebin by means of electronic circular dichroism (ECD), supported by quantum chemical calculations. The comparison of experimental ECD with the corresponding quantum chemical prediction for the proper diastereoisomer resulted in the definitive assignment of the AC of the
J. Braz. Chem. Soc.. Publicado em: 2020-10
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18. Isolation, Absolute Configuration and Cytotoxic Activities of Alkaloids from Hippeastrum goianum (Ravenna) Meerow (Amaryllidaceae)
The phytochemical study of Hippeastrum goianum led to the identification of 13 compounds by means of gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). Compounds 7-demethoxy-9-O-methylhostasine (1) and 7-deoxi-trans-dihydronarciclasine (2) had their absolute configurations determined by vibrational circular dichroism (VCD). Th
J. Braz. Chem. Soc.. Publicado em: 2020-10
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19. Synthesis, in silico Study, Theoretical Stereochemistry Elucidation and Antifungal Activity of New Imides Derived from Safrole
Ten imides derived from safrole, 4a-4j, were synthesized and their structures were fully characterized by infrared (IR) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and high resolution mass spectrometry (HRMS) analysis. Among the ten imides studied, eight are new. The compounds were evaluated in an in silico study and showed strong
J. Braz. Chem. Soc.. Publicado em: 2020-10
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20. Novel N-Heterocyclic Carbene Silver(I) Complexes: Synthesis, Structural Characterization, Antimicrobial and Cytotoxicity Potential Studies
In this study, a series of unsymmetrical N,N-disubstituted benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) (2a-2j) and their AgI complexes. Their structures were characterized by elemental analyses, 1H and 13C nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy techniques. Further, both the salts and their silver(I)-NHC com
J. Braz. Chem. Soc.. Publicado em: 2020-10
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21. Copaifera multijuga, Copaifera pubiflora and Copaifera trapezifolia Oleoresins: Chemical Characterization and in vitro Cytotoxic Potential against Tumoral Cell Lines
Copaifera species (Fabaceae) comprises approximately 70 species of large trees, from which 16 can be found in Brazil. The oleoresins obtained from their trunk are widely used in Brazilian folk medicine, which display important antitumoral potential. Chemically, these oleoresins are mainly composed of a mixture of sesquiterpenes and diterpenes. In this paper
J. Braz. Chem. Soc.. Publicado em: 2020-08
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22. Combined Analytical Py-GC/MS, SEM, FTIR and 13C NMR for Investigating the Removal of Trace Metals from Aqueous Solutions by Biochar
In this study, the efficiency of biochar (BC) produced from sugarcane bagasse at different pyrolysis temperatures (300, 400, 500 and 600 ºC) for simultaneous removal of CdII, PbII, CuII, CrIII, NiII and ZnII ions from aqueous solutions was assessed. All BC were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), 13C nu
J. Braz. Chem. Soc.. Publicado em: 2020-07
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23. 3-Aminofurostane Alkaloids from Solanum paniculatum (“Jurubeba Verdadeira”) Roots
The roots of Solanum paniculatum (Solanaceae) have extensively been used in folk medicine to treat liver infections and as a diuretic. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) were used for the profiling and structural characterization of alkaloids from the roots of S. paniculatum. Six
J. Braz. Chem. Soc.. Publicado em: 2020-05
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24. Easy Epoxidation of Monoterpenes from Common Starting Materials
Epoxidation of monoterpenes, α-pinene, β-pinene, limonene, α-terpinene, and (R)-carvone was carried out by the in situ production of a peroxyacid rather than direct addition of such an expensive and difficult to handle chemical. Previous reports showed use of metal catalysts with high yields, while methodologies without catalysts at high temperature showe
J. Braz. Chem. Soc.. Publicado em: 2020-05