Navegando por Palavras-chave "ionic liquid"

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    Application of an Ionic Liquid in the Microwave Assisted Extraction of Cytotoxic Metabolites from Fruits of Schinus terebinthifolius Raddi (Anacardiaceae)
    (Soc Brasileira Quimica, 2017) Morais, Thiago R. [UNIFESP]; Coutinho, Ana Paula R. [UNIFESP]; Camilo, Fernanda F. [UNIFESP]; Martins, Tereza S. [UNIFESP]; Sartorelli, Patricia [UNIFESP]; Massaoka, Mariana H. [UNIFESP]; Figueiredo, Carlos R. [UNIFESP]; Lago, Joao Henrique G. [UNIFESP]
    This work reports the application of an ionic liquid (1-butyl-3-methylimidazolium bromide, BMImBr) in the microwave assisted extraction (MAE) of metabolites from fruits of Schinus terebinthifolius. Dried fruits were individually extracted using BMImBr: H2O 1: 1, v/v (experiment 1) and pure H2O (experiment 2) by MAE (10 min at 60 degrees C). After partition using EtOAc, the yield to experiment 1 was about 23% while to experiment 2 was 0.1%. The EtOAc fraction obtained from experiment 1 was purified by chromatographic methods to afford 3-oxotirucalla-7,24Z-dien27- oic acid, 3a-hydroxytirucalla-7,24Z-dien-27-oic acid, 3 alpha-acetoxytirucalla-7,24Z-dien-27-oic acid, gallic acid, and ethyl gallate, being the first occurrence of the third compound as natural product. Cytotoxic activity was evaluated in vitro against cancer cell lines (A2058, HeLa, SiHa, HCT, SKBR-3, U87, and B16F2Nex2), being 3 alpha-acetoxytirucalla-7,24Z-dien-27-oic acid the more active metabolite with IC50 ranging from 10.9 +/- 1.3 to 17.3 +/- 1.4 mu g mL(-1), lower than that determined to positive control cisplatin.
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    Imidazolium Ionic Liquid Mediates Black Phosphorus Exfoliation while Preventing Phosphorene Decomposition
    (Amer Chemical Soc, 2017) Chaban, Vitaly V. [UNIFESP]; Fileti, Eudes Eterno [UNIFESP]; Prezhdo, Oleg V.
    Forthcoming applications in electronics and optoelectronics make phosphorene a subject of vigorous research efforts. Solvent-assisted exfoliation of phosphorene promises affordable delivery in industrial quantities for future applications. We demonstrate, using equilibrium, steered and umbrella sampling molecular dynamics, that the 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM] [BF4] ionic liquid is an excellent solvent for phosphorene exfoliation. The presence of both hydrophobic and hydrophilic moieties, as well as substantial shear viscosity, allows [EMIM] [BF4] simultaneously to facilitate separation of phosphorene sheets and to protect them from getting in direct contact with moisture and oxygen. The exfoliation thermodynamics is moderately unfavorable, which indicates that an external stimulus is necessary. Unexpectedly, [EMIM][BF4] does not coordinates phosphorene by pi-electron stacking, with the imidazole ring. Instead, the solvation proceeds via hydrophobic side chains, while polar imidazole rings form an electrostatically stabilized protective layer. The simulations suggest that further efforts in solvent engineering for phosphorene exfoliation should concentrate on use of weakly coordinating ions and grafting groups that promote stronger dispersion interactions and on elongation of nonpolar chains.
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    Synthesis of Lapachone Derivates via Ionic Liquid-Mediated Tandem Knoevenagel/Diels-Alder Reaction
    (Wiley-V C H Verlag Gmbh, 2017) Prado, Karinne E.; Name, Luccas L.; Oliveira, Rayssa P.; Guadagnin, Rafael C. [UNIFESP]; Pimenta, Daniel C.; Pena, Jesus M.; Cella, Rodrigo
    The use of ionic liquid (IL) in Tandem Knoevenagel/Diels-Alder Reaction is an optimization method for one-pot procedures, providing great results under mild conditions. In this paper, four new Lapachone derivatives were obtained using lawsone as substrate. The effects of the catalytic use of ionic liquids and catalysts in organometallic systems were evaluated. Several lapachone derivatives were obtained good to excellent yields.