Aromatic Substituents
Mostrando 1-12 de 50 artigos, teses e dissertações.
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1. Novel Greener Microwave-Assisted Deprotection Methodology for the 1,3-Dioxolane Ketal of Isatin Using Calix[n]arenes
In this work, the combined use of p-sulfonic acid-calix[n]arene and microwave energy to hydrolyze the 1,3-dioxolane ketal of isatin was evaluated with excellent results. This is the first time that p-sulfonic acid-calix[n]arene has been used as the catalyst in a ketal hydrolysis reaction and the deprotection of the ketone carbonyl of isatin is reported. The
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. EVALUATION OF THE CHEMICAL COMPOSITION AND STRUCTURE OF ASPHALTENES FROM THREE OFFSHORE BRAZILIAN BIODEGRADED HEAVY OILS
Asphaltenes fractions were extracted and purified from three heavy Brazilian oils. Their mass compositions of C, H, N, Ni and V were obtained from elemental analysis and S and O atomic percentages from EDS. The H/C ratios showed high degree of unsaturation, while the O atomic percentages indicated more pronounced biodegradation effects on two samples. Quanti
Quím. Nova. Publicado em: 2021-04
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3. Structural Study of Phenolic Acids by Triple Quadrupole Mass Spectrometry with Electrospray Ionization in Negative Mode and H/D Isotopic Exchange
This work reports the theoretical and experimental study of fragmentation reactions in the gas phase of five phenolic acids using triple quadrupole mass spectrometry by electrospray ionization in negative ionic mode, as well as the isotope exchange experiments. MS/MS spectra were analyzed to suggest the fragmentation mechanisms, while theoretical calculation
J. Braz. Chem. Soc.. Publicado em: 2020-02
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4. DFT Study of the Interaction between the Ni2+ and Zn2+ Metal Cations and the 1,2-Dithiolene Ligands: Electronic, Geometric and Energetic Analysis
Density functional theory (DFT) (B3LYP/6-311++G(d,p)) calculations of the interacting strength 1,2-dithiolene anionic ligands with the [M(OH2)4]2+ and [M(OH2)2]2+ complexes (M = Ni and Zn) were performed. Three series of ligands were studied: compounds with an aromatic ring, with an ethylene moiety and with a heterocyclic ring. The ligands have substituents
J. Braz. Chem. Soc.. Publicado em: 23/05/2019
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5. Synthesis and Cytotoxic Evaluation of 1H-1,2,3-Triazol-1-ylmethyl-2,3-dihydronaphtho[1,2-b]furan-4,5-diones
ABSTRACT The 1,2-naphthoquinone compound was previously considered active against solid tumors. Moreover, glycosidase inhibitors such as 1,2,3-1H triazoles has been pointed out as efficient compounds in anticancer activity studies. Thus, a series of eleven 1,2-naphthoquinones tethered in C2 to 1,2,3-1H-triazoles 9a-k were designed, synthesized and their cyto
An. Acad. Bras. Ciênc.. Publicado em: 15/02/2018
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6. Computational Study of Electronic Effects from β-Substituents on the Tautomerism of Naphthazarin Derivatives
In this work, semi-empirical AM1 and DFT B3LYP/6-31G** calculations were applied in the study of the interconversion among tautomers of several naphthazarin and 5-amino-8-hydroxy-1,4-naphthoquinone β-substituted derivatives bearing electron-donor or electron-withdrawing groups. Using a semi-empirical method, detailed potential energy landscapes for proton t
J. Braz. Chem. Soc.. Publicado em: 2017-04
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7. Flavonoid electrochemistry: a review on the electroanalytical applications
Flavonoids are polyphenolic compounds widespread in vegetal kingdom. They present a C-15 skeleton, which is divided into three units A, B and C. Unit C is an oxygen containing heterocyclic, whose oxidation state and saturation level define major subclasses. Units A and B are aromatic rings, in which four major types of substituents, i. e. hydroxyl, methoxyl,
Rev. bras. farmacogn.. Publicado em: 10/05/2013
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8. ReaÃÃes biocatalÃticas usando cÃlulas Ãntegras de Lens culinaris (Lentilha). / REACTIONS USING WHOLE CELL BIOCATALYTIC LENS CULINARIS (LENTIL)
This paper describes the use of seeds of lentil (Lens culinaris) as intact plant system in biocatalytic reactions of reduction and hydrolysis. Initially, some plant sources were evaluated for their action in the biocatalytic reduction of aromatic ketone acetophenone. The plants that showed positive results in the reduction reaction underwent determination of
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/10/2012
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9. SYNTHESIS,CHARACTERIZATION AND THEORETICAL STUDY OF ORTHO-SUBSTITUTED SCHIFF BASES AND THEIR COPPER(II) COMPLEXES AS POTENTIAL ANTITUMOR AGENTS / SÍNTESE, CARACTERIZAÇÃO E ESTUDO TEÓRICO DE BASES DE SCHIFF ORTO-SUBSTITUÍDAS E SEUS COMPLEXOS DE COBRE(II) COMO POTENCIAIS AGENTES ANTITUMORAIS
Nowadays, the neoplastic processes have been one of the most concern diseases. The malignance tumor, also called cancer, is the most aggravating pathological process, responsible for the death of the patient in most cases. In this context, several drugs have been designed with the objective to eliminate the cancer cells selectively; among them, some coordina
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/02/2012
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10. Estudo da estrutura eletrônica de compostos mesoiônicos
Mesoionic compounds are a class of molecules which have attracted the interest of scientific community since the late nineteenth century. Their unique structure has proved to be a challenge for researchers who intended to satisfactorily describe and define it. Those compounds are five-membered heterocyclic rings which possess a delocalized structure
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/09/2011
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11. Oligomerização de olefinas leves catalisada por complexos contendo ligantes B-diimina heterogeneizados em sílica
This work describes ¿-diimine ligands synthesis and the corresponding nickel complexes, homogeneous and heterogeneized, its catalytic application in ethylene oligomerization. Initially held the ¿-diimine ligands synthesis with different substituents in the aromatic ring. These ligands were characterized by CHN elemental analysis, IR, UV-Vis and 1H NRM. Fro
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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12. Biological activity of amides and analogs from Piper species and synthetic analogs / Atividade biológica de amidas e análogos de espécies de Piper e estudos biossintéticos
Six amides were isolated from Piper scutifolium and P. corcovadensis including piperovatine, piperlonguminine, isopiperlonguminine and corcovadine, the new scutifoliamide A and scutifoliamide B and also two aristolactams (piperolactam C and stigmalactam). From P. tuberculatum the amides piplartine and pellitorine and two esters, ethyl (E)-3,4,5-trimethoxycin
Publicado em: 2009