Thf
Mostrando 1-12 de 163 artigos, teses e dissertações.
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1. Ketones as Electrophile in Nitroaldol Reaction: Synthesis of β,β-Disubstituted- 1,3-dinitroalkanes and Allylic Nitro Compounds
Abstract β,β-Disubstituted-1,3-dinitro compounds were obtained exclusively with an overall yield of 83% through a domino nitroaldol/elimination/1,4-addition process, when excess nitromethane was added to cyclohexanone or butanone using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), as a basic catalyst. On the other hand, β-nitroalcohols could be obtained in 30
J. Braz. Chem. Soc.. Publicado em: 2021-08
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2. 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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3. Production of Medical Grade Silicone for Facial Prosthesis with Bactericidal Properties from the Inclusion of Poly (Diallyldimethylammonium Chloride): An in Vitro Study
Abstract Objective: To evaluate the inclusion capacity and bactericidal efficiency of diallyl dimethyl ammonium chloride (PDADMAC) diluted in tetrahydrofuran (THF) upon inclusion in the medical grade silicone polymer structure. Material and Methods: It was diluted the PDADMAC in THF at the concentration of 4wt%. It was included in the silicon paste during
Pesqui. Bras. Odontopediatria Clín. Integr.. Publicado em: 02/09/2019
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4. Production of Furan Compounds from Sugarcane Bagasse Using a Catalytic System Containing ZnCl2/HCl or AlCl3/HCl in a Biphasic System
In this work, two catalytic systems combining Lewis and Brønsted acids (ZnCl2/HCl and AlCl3/HCl) were applied in a tetrahydrofuran (THF)/NaClaq biphasic system to produce furan compounds from plant polysaccharides. The following cellulosic matrices were applied for this purpose: α-cellulose, microcrystalline cellulose and both native and steam-exploded sug
J. Braz. Chem. Soc.. Publicado em: 2018-05
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5. Improved Reactivity in the Ring-Opening Polymerization of ε-Caprolactone with a Trinuclear Titanium(IV) Oxochloroneopentoxide as Initiator
The complex [Ti3(O)(Cl)(ONep)9] and two iron(II)-containing products, [Fe4Cl8(thf)6] and [Fe2Cl3(thf)6][FeCl4], were synthesized by a redox reaction involving [Ti3(OiPr)11][FeCl4] and neopentanol; the structures of compounds [Ti3(O)(Cl)(ONep)9] and [Fe2Cl3(thf)6][FeCl4] have been confirmed by X-ray diffraction methods. Variable-temperature 1H NMR analysis of
J. Braz. Chem. Soc.. Publicado em: 2017-08
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6. Synthesis, Characterization and Ethylene Oligomerization Studies of Chromium Complexes Bearing Imino-Furfural Ligands
Uma série de complexos de cromo(III) contendo ligantes imina-furfural (Cr1-Cr4) foram sintetizados e caracterizados por espectrometria de massas de alta resolução (HRMS). Todos os pré-catalisadores de cromo, ativados com metilaluminoxano (MAO), apresentaram atividade moderada na oligomerização do etileno [frequência de rotação (TOF) = 11.800-23.200
J. Braz. Chem. Soc.. Publicado em: 2014-12
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7. Synthesis of unsymmetrical aryl-ethynylated benzenes via regiocontrolled Sonogashira reaction of 1,3,5-tribromobenzene
O acoplamento de Sonogashira do trimetilsililacetileno com 4-alcóxi-1-iodobenzenos resultou em 2-(4-(alquilóxi)fenil)etiniltrimetilsilanos, que sofrem desproteção pela retirada do grupo TMS usando fluoreto de tetrabutilamônio (TBAF) em THF à temperatura ambiente, resultando nos 2-(4-(alquilóxi)fenil)acetilenos terminais correspondentes. O acoplamento
J. Braz. Chem. Soc.. Publicado em: 2014-09
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8. Measurement and correlation of isobaric vapor-liquid equilibrium for the binary system of cyclopentane and tetrahydrofuran
Isobaric vapor-liquid equilibrium (VLE) data for the cyclopentane and tetrahydrofuran (THF) system were measured at 101.3 kPa by using an equilibrium still. Thermodynamic consistency of the experimental data was confirmed by means of the Herington method. The experimental data were correlated and calculated by the Margules, Van Laar and Wilson activity-coeff
Braz. J. Chem. Eng.. Publicado em: 2014-09
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9. Simultaneous analysis of T helper subsets (Th1, Th2, Th9, Th17, Th22, Tfh, Tr1 and Tregs) markers expression in periapical lesions reveals multiple cytokine clusters accountable for lesions activity and inactivity status
Previous studies demonstrate that the balance between pro- and anti-inflammatory mediators determines the stable or progressive nature of periapical granulomas by modulating the balance of the osteoclastogenic factor RANKL and its antagonist OPG. However, the cytokine networks operating in the development of periapical lesions are quite more complex than wha
J. Appl. Oral Sci.. Publicado em: 2014-07
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10. Polímeros de impressão molecular obtidos através de polimerização por precipitação e sua aplicação na técnica de extração em fase sólida
Polímeros de impressão molecular (Molecularly Imprinted Polymers, MIPs) foram sintetizados e aplicados como adsorventes na técnica de extração em fase sólida (EFS). O método de polimerização por precipitação foi usado para sintetizar os polímeros, devido à simplicidade de preparo, altos rendimentos e obtenção de partículas mais uniformes uma
Polímeros. Publicado em: 18/06/2013
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11. Stereoselective total synthesis of the potent anti-asthmatic compound CMI-977 (LDP-977)
Neste trabalho, uma síntese curta e eficiente para o CMI-977 (LDP-977), um potente agente antiasmático oralmente ativo, é descrita. As etapas chave envolveram uma ciclização oxidativa de Mukaiyama, fornecendo a unidade trans-THF (tetrahidrofurano) e uma reação de homologação de Seyferth-Gilbert para construção da tripla ligação da molécula alvo
J. Braz. Chem. Soc.. Publicado em: 2013-02
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12. Nanocompósitos PVC/nanotubos de carbono: avaliação da resistividade elétrica e efeito do solvente utilizado na obtenção dos nanocompósitos nas propriedades térmicas
O procedimento de obtenção de nanocompósitos dispersando as nanopartículas na matriz polimérica em solução com posterior eliminação do solvente tem sido bastante utilizado, considerando a maior eficiência de obtenção de homogeneidade do produto final. Entretanto, a presença de solvente residual nos nanocompósitos pode afetar as propriedades mic
Polímeros. Publicado em: 2013