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1.
Ricardo Ferraz Marina Pinheiro Ana Gomes Cátia Teixeira Cristina Prudêncio Salette Reis Paula Gomes 《Bioorganic & medicinal chemistry letters》2017,27(17):4190-4193
Primaquine-based ionic liquids, obtained by acid-base reaction between parent primaquine and cinnamic acids, were recently found as triple-stage antimalarial hits. These ionic compounds displayed significant activity against both liver- and blood-stage Plasmodium parasites, as well as against stage V P. falciparum parasites. Remarkably, blood-stage activity of the ionic liquids against both chloroquine-sensitive (3D7) and resistant (Dd2) P. falciparum strains was clearly superior to those of the respective covalent (amide) analogues and of parent primaquine. Having hypothesized that such behaviour might be ascribed to an enhanced ability of the ionic compounds to permeate into Plasmodium-infected erythrocytes, we have carried out a differential scanning calorimetry-based study of the interactions between the ionic liquids and membrane models. Results provide evidence, at the molecular level, that the primaquine-derived ionic liquids may contribute to an increased permeation of the parent drug into malaria-infected erythrocytes, which has relevant implications towards novel antimalarial approaches based on ionic liquids. 相似文献
2.
Enzymatic selective acylation of glycosides in ionic liquids: significantly enhanced reactivity and regioselectivity 总被引:5,自引:0,他引:5
Mahn-Joo Kim Min Young Choi Jae Kwan Lee Yangsoo Ahn 《Journal of Molecular Catalysis .B, Enzymatic》2003,26(3-6):115-118
The enzymatic selective acylations of carbohydrates in ionic liquids were explored in both organic solvents and ionic liquids to see any significant differences in terms of reactivity and regioselectivity between two different classes of reaction media. Monoprotected glycosides (methyl-6-O-trityl-glucosides and galactosides) were chosen as the substrates with Candida rugosa lipase as an acylation enzyme. Two organic solvents, THF and chloroform, and two ionic liquids, [BMIM]+PF6− ([BMIM]+ = 1-butyl-3-methylimidazolium) and [MOEMIM]+PF6− ([MOEMIM]+ = 1-methoxyethyl-3-methylimidazolium), were employed as reaction media. The enzymatic reactions were performed in the presence of vinyl acetate at room temperature. It was observed that the reactions in ionic liquids took place more rapidly and more selectively than those in conventional organic solvents. 相似文献
3.
Influence of acidity and structure of ionic liquids on microcrystalline cellulose (MCC) hydrolysis was investigated. MnCl2-containing ionic liquids (ILs) were efficient catalysts and achieved MCC conversion rates of 91.2% and selectivities for 5-hydroxymethyl furfural (HMF), furfural and levulinic acid (LA) of 45.7%, 26.2% and 10.5%, respectively. X-ray diffractometry indicated that catalytic hydrolysis of MCC in ionic liquids resulted in the changes to MCC crystallinity and transformation of cellulose I into cellulose II. SO3H-functionalized ionic liquids showed higher activities than non-functionalized ILs. The simplicity of the chemical transformation of cellulose provides a new approach for the use this polymer as raw material for renewable energy and chemical industries. 相似文献
4.
5.
Scope and limitations of imidazolium-based ionic liquids as room temperature glycosylation promoters
The scope and limitations of imidazolium-based ionic liquids as room temperature glycosylation promoters have been studied. Herein, we report the effects of modifying the structure of the imidazolium cation and how important the choice of counter ion becomes on model glycosylation reactions of thioglycosides at room temperature in the presence of N-iodosuccinimide (NIS). 相似文献
6.
Efficient conversion of glucose to 5-hydroxymethyl furfural (5-HMF), a platform chemical for fuels and materials, was achieved using CrCl2 or CrCl3 as the catalysts with inexpensive co-catalysts and solvents including halide salts in dimethyl sulfoxide (DMSO) and several ionic liquids. 5-HMF (54.8%) yield was achieved with the CrCl2/tetraethyl ammonium chloride system at mild reaction conditions (120 °C and 1 h). The 5-HMF formation reaction was found to be faster in ionic liquids than in the DMSO system. Effects of water in the reaction system, chromium valence and reaction temperature on the conversion of glucose into 5-HMF were discussed in this work. 相似文献
7.
We herein report O-glycosidation reactions promoted via silver N-heterocyclic carbene complexes formed in situ in ionic liquids. Seven different room temperature ionic liquids were screened for the glycosidation reaction of 4-nitrophenol with tetra-O-acetyl-α-d-galactopyranosyl bromide. Good to excellent yields were obtained using Ag–NHC complexes derived from imidazolium halide salts to promote the glycosidation reaction, whereas yields considered moderate to low were obtained without use of the silver carbene complex. Anion metathesis of the ionic liquids with inexpensive alkylammonium halides also resulted in silver N-heterocyclic carbene formation and subsequent O-glycosidation in the presence of silver carbonate. Effective utility of this methodology has been demonstrated with biologically relevant acceptors (including flavones and steroids) where O-β-glycoside products were obtained selectively in moderate to good yields. We have also demonstrated that the Ag–NHC complex is a superior promoter to traditionally used silver carbonate for the glycosidation of polyphenolic acceptors. The ionic liquids used in the study could be recycled three times without apparent loss in activity. 相似文献
8.
Dishun Zhao He LiJuan Zhang Linlin FuMengshuai Liu Jiangtao FuPeibing Ren 《Carbohydrate polymers》2012,87(2):1490-1494
Two kinds of alkylimidazolium salts containing dimethyl phosphate or diethyl phosphate were obtained as room temperature ionic liquids synthesized by one step, and both of them have the ability to dissolve untreated cellulose. Especially, 1-ethyl-3-methylimidazolium diethylphosphonate ([EMIM]DEP) could obtain 4 wt% cellulose solution within 10 min under 90. The effects of dissolution temperature on cellulose dissolution time and degree of polymerization were investigated. As dissolution temperature increased, dissolution time was greatly reduced. Both the original and regenerated cellulose samples were characterized with wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron micrograph. The results showed that the crystalline structure of cellulose was converted to cellulose II from cellulose I in native cellulose. It was also found that the regenerated cellulose had good thermal stability with [EMIM]DEP ionic liquid. 相似文献
9.
The purpose of this article was to explore an environmentally friendly strategy to synthesis of biomass-based hybrids. Herein, microwave-assisted ionic liquids method was applied to fabricate the hybrids from cellulose and AgX (X = Cl, Br) using cellulose and AgNO3. The ionic liquids act simultaneously as a solvent, a microwave absorber, and a reactant. Ionic liquids provided Cl− or Br− to the synthesis of AgCl or AgBr crystals; thus no additional reactant is needed. The products are characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The cellulose–Ag/AgCl hybrid and cellulose–Ag/AgBr hybrid were also obtained by using cellulose–AgCl and cellulose–AgBr hybrids as precursors. This environmentally friendly microwave-assisted ionic liquids method is beneficial to the hybrids with high dispersion. 相似文献
10.
《Biocatalysis and Biotransformation》2013,31(4):331-338
The activity of three different lipases, a glycosidase and a protease in ionic liquids has been studied. Ambient temperature ionic liquids are a new class of solvents that are nonvolatile and nonflammable and thus an interesting alternative to classical organic solvents. Monitoring the synthesis of a simple ester, all lipases were found to exhibit both excellent activity and stability in the non-polar ionic liquid 1-butyl-3-methylimidazohum hexaflurophosphate ([bmin][PF6], 1). Furthermore, β-galactosidase from E. coli and the Subtilisin protease SavinaseTM were both found to exhibit a hydrolytic activity in a 50% aqueous solution of the water-miscible ionic liquid 1-butyl-3-methyhmidazoUum tetra-fluoroborate ([bmin][BF4], 2) comparable to the activity observed in 50% aqueous solutions of ethanol and acetonitrile. 相似文献
11.
Fabrication of biomass materials by a microwave-assisted method in ionic liquids allows the high value-added applications of biomass by combining three major green chemistry principles: using environmentally preferable solvents, using an environmentally friendly method, and making use of renewable biomass materials. Herein, we report a rapid and green microwave-assisted method for the synthesis of the cellulose/calcium silicate nanocomposites in ionic liquids and recycled ionic liquids. These calcium silicate nanoparticles or nanosheets as prepared were homogeneously dispersed in the cellulose matrix. The experimental results confirm that the ionic liquids can be used repeatedly. Of course, the slight differences were also observed using ionic liquids and recycled ionic liquids. Compared with other conventional methods, the rapid, green, and environmentally friendly microwave-assisted method in ionic liquids opens a new window to the high value-added applications of biomass. 相似文献
12.
Refolding of horseradish peroxidase is enhanced in presence of metal cofactors and ionic liquids
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The effects of various refolding additives, including metal cofactors, organic co‐solvents, and ionic liquids, on the refolding of horseradish peroxidase (HRP), a well‐known hemoprotein containing four disulfide bonds and two different types of metal centers, a ferrous ion‐containing heme group and two calcium atoms, which provide a stabilizing effect on protein structure and function, were investigated. Both metal cofactors (Ca2+ and hemin) and ionic liquids have positive impact on the refolding of HRP. For instance, the HRP refolding yield remarkably increased by over 3‐fold upon addition of hemin and calcium chloride to the refolding buffer as compared to that in the conventional urea‐containing refolding buffer. Moreover, the addition of ionic liquids [EMIM][Cl] to the hemin and calcium cofactor‐containing refolding buffer further enhanced the HRP refolding yield up to 80% as compared to 12% in conventional refolding buffer at relatively high initial protein concentration (5 mg/ml). These results indicated that refolding method utilizing metal cofactors and ionic liquids could enhance the yield and efficiency for metalloprotein. 相似文献
13.
Pedro Lozano Teresa De Diego Said Gmouh Michel Vaultier José L. Iborra 《Biocatalysis and Biotransformation》2013,31(3-4):169-176
The stability of α-chymotrypsin and Candida antarctica lipase B (CALB) in two ionic liquids (i.e. 1-ethyl-3-methyl-imidazolium, bis[(trifluoromethyl)sulfonyl]imide [emim] [NTf2], and butyl-trimethylamonium bis[(trifluoromethyl)sulfonyl]imide [btma] [NTf2]) has been studied. Both enzymes were strongly stabilized by the ionic liquids, the respective half-life times increasing 96 and 1660 times, with respect to those obtained in classical organic solvents such as 1-propanol and hexane, respectively. The stabilization of both enzymes by ionic liquids may be related to the associated structural changes of proteins that they can be observed by both fluorescence and circular dichroism spectroscopic studies. 相似文献
14.
Penicillin acylase catalysis in the presence of ionic liquids 总被引:2,自引:0,他引:2
Several ionic liquids were used as reaction media for penicillin G acylase catalysis. In all the assayed ionic liquids, [bmim]PF6 proved good media for PGA-catalyzed hydrolysis. A novel [bmim]PF6/water two-phase system is provided for 6-aminopenicillanic acid (APA) production, which will be more benefical than aquous batch systems used widely in industrial production of APA. 相似文献
15.
Ionic liquids, 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIm][PF6]) and 1-ethyl-3-methyl imidazolium hexafluorophosphate ([EMIm][PF6]), were used for the methanolysis of sunflower oil using Candida antarctica lipase (Novozyme 435) and gave yields of fatty acid methyl esters at 98–99% within 10 h. The optimum conditions of methanolysis
in hydrophobic ionic liquids are 2% (w/w) lipase, 1:1 (w/w) oil/ionic liquid and 1:8 (mol/mol) oil/methanol at 58–60°C. Methanolysis
using hydrophilic ionic liquids, 3-methyl imidazolium tetrafluoroborate ([HMIm][BF4]) and 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIm][BF4]), gave very poor yields. A hydrophobic ionic liquid thus protects the lipase from methanol. Recovered ionic liquids and
lipase were used for four successive reaction cycles without any significant loss of activity. 相似文献
16.
Ionic liquids are considered as an alternative to organic solvents for catalysis. The literature in this field is reviewed
with focus on advantageous use of ionic liquids in biocatalysis and biotransformations. The overview reveals that the exploration
and mapping of ionic liquids with respect to biocatalysis is still sketchy. It is apparent that advantages can be gained in
view of activity, stability and selectivity. Furthermore, integration of reaction and separation has a high potential in the
field. The review presents quantitative data on the productivities, space–time yields, as well as stability as far as they
can be extracted from the literature.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Sang Hyun Lee Thanh Thi Ngoc Doan Sung Ho Ha Woo-Jin Chang Yoon-Mo Koo 《Journal of Molecular Catalysis .B, Enzymatic》2007,47(3-4):129-134
The immobilization of lipase from Candida rugosa, using ionic liquids as additives to protect the inactivation of lipase by released alcohol and shrinking of gel during sol–gel process, was investigated. The influence of various factors, such as structure of ionic liquids, content of ionic liquids and types of precursor in the sol–gel process on the activity and stability of immobilized lipase was also studied. The highest hydrolytic activity of immobilized lipase was obtained when the hydrophilic ionic liquid, [C2mim][BF4], was used as an additive, while the highest stability of immobilized lipase was obtained by using hydrophobic ionic liquid, [C16mim][Tf2N]. Therefore, the binary mixtures of these ionic liquids as additives were used to obtain the optimal immobilized lipase, which shows both high activity and stability. The hydrolysis and esterification activities of lipase co-immobilized with the mixture of 1:1 at molar ratio of [C2mim][BF4] and [C16mim][Tf2N] were 10-fold and 14-fold greater than in silica gel without ionic liquids (ILs), respectively. After 5 days incubation of this immobilized lipase in n-hexane at 50 °C, 84% of initial activity was remained, while the residual activity of the lipase immobilized without ILs was 28%. 相似文献
18.
Activity of mushroom tyrosinase was studied in three ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) and 1-butyl-3-methylimidazolium methylsulfate ([BMIm][MeSO4]), and was compared to that in chloroform. Kinetic parameters of the enzyme were determined and the results indicate that
the enzyme in ionic liquids basically follows the same catalytic mechanism as in water, and that the ionic liquids may affect
the enzyme activity by direct interacting with the enzyme and thus hindering the E–S binding due to their high hydrophilicity
and polarity. 相似文献
19.
Lisa Warner Erica Gjersing Shelby E. Follett K. Wade Elliott Sergei V. Dzyuba Krisztina Varga 《Biochemistry and Biophysics Reports》2016
Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentrations of ionic liquids, has been challenging. In the present work the 13C, 15N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid–protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C4-mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6–3.5 M, which corresponds to 10–60% v/v). Interactions between GB1 and [C4-mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C4-mim]Br were assigned using 3D methods under HR-MAS conditions. Thus, HR-MAS NMR is a viable tool that could aid in elucidation of molecular mechanisms of ionic liquid–protein interactions. 相似文献
20.
Biodegradation of diesel fuel by a microbial consortium in the presence of 1-alkoxymethyl-2-methyl-5-hydroxypyridinium chloride homologues 总被引:1,自引:0,他引:1
Łukasz Chrzanowski Monika Stasiewicz Mikołaj Owsianiak Alicja Szulc Agnieszka Piotrowska-Cyplik Agnieszka K. Olejnik-Schmidt Bogdan Wyrwas 《Biodegradation》2009,20(5):661-671
Fast development of ionic liquids as gaining more and more attention valuable chemicals will undoubtedly lead to environmental
pollution. New formulations and application of ionic liquids may result in contamination in the presence of hydrophobic compounds,
such as petroleum mixtures. We hypothesize that in the presence of diesel fuel low-water-soluble ionic liquids may become
more toxic to hydrocarbon-degrading microorganisms. In this study the influence of 1-alkoxymethyl-2-methyl-5-hydroxypyridinium
chloride homologues (side-chain length from C3 to C18) on biodegradation of diesel fuel by a bacterial consortium was investigated. Whereas test performed for the consortium cultivated
on disodium succinate showed that toxicity of the investigated ionic liquids decreased with increase in side-chain length,
only higher homologues (C8–C18) caused a decrease in diesel fuel biodegradation. As a result of exposure to toxic compounds also modification in cell surface
hydrophobicity was observed (MATH). Disulphine blue active substances method was employed to determine partitioning index
of ionic liquids between water and diesel fuel phase, which varied from 1.1 to 51% for C3 and C18 homologues, respectively. We conclude that in the presence of hydrocarbons acting as a solvent, the increased bioavailability
of hydrophobic homologues is responsible for the decrease in biodegradation efficiency of diesel fuel. 相似文献