- Amino acid variability in the peptide composition of a suite of amphiphilic peptide siderophores from an open ocean Vibrio species
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In response to iron-depleted aerobic conditions, bacteria often secrete low molecular weight, high-affinity iron(III)-complexing ligands, siderophores, to solubilize and sequester iron(III). Many marine siderophores are amphiphilic and are produced in suites, wherein each member within a particular suite has the same iron(III)-binding polar head group which is appended by one or two fatty acids of differing length, degree of unsaturation, and degree of hydroxylation, establishing the suite composition. We report the isolation and structural characterization of a suite of siderophores from marine bacterial isolate Vibrio sp. Nt1. On the basis of structural analysis, this suite of siderophores, the moanachelins, is amphiphilic and composed of two N-acetyl-N-hydroxy-d- ornithines, one N-acetyl-N-hydroxy-l-ornithine, and either a glycine or an l-alanine, appended with various saturated and unsaturated fatty acid tails. The variation in the small side-chain amino acid is the first occurrence of variation in the peptidic head group structure of a set of siderophores produced by a single bacterium.
- Gauglitz, Julia M.,Butler, Alison
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- Soluble asphaltene oxide: A homogeneous carbocatalyst that promotes synthetic transformations
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Carbocatalysts, materials which are predominantly composed of carbon and catalyze the synthesis of organic or inorganic compounds, are promising alternatives to metal-based analogues. Even though current carbocatalysts have been successfully employed in a broad range of synthetic transformations, they suffer from a number of drawbacks in part due to their heterogeneous nature. For example, the insolubility of prototypical carbocatalysts, such as graphene oxide (GO), may restrict access to catalytically-active sites in a manner that limits performance and/or challenges optimization. Herein we describe the preparation and utilization of soluble asphaltene oxide (sAO), which is a novel material that is composed of oxidized polycyclic aromatic hydrocarbons and is soluble in a wide range of organic solvents as well as in aqueous media. sAO promotes an array of synthetically useful transformations, including esterifications, cyclizations, multicomponent reactions, and cationic polymerizations. In many cases, sAO was found to exhibit higher catalytic activities than its heterogeneous analogues and was repeatedly and conveniently recycled, features that were attributed to its ability to form homogeneous phases.
- Bielawski, Christopher W.,Jung, Hyosic
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- Solid acid catalysts for biodiesel production - Towards sustainable energy
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The advantages of biodiesel as an alternative fuel and the problems involved in its manufacturing are outlined. The pros and cons of making biodiesel via fatty acid esterification using solid acid catalysts are examined. The main problem is finding a suitable catalyst that is active, selective, and stable under the process conditions. Various solid acids (zeolites, ion-exchange resins, and mixed metal oxides) are screened as catalysts in the esterification of dodecanoic acid with 2-ethylhexanol, 1-propanol, and methanol at 130-180°C. The most promising candidate is found to be sulphated zirconia. The catalyst's stability towards thermal decomposition and leaching is tested and the effects of the surface composition and structure on the catalytic activity are discussed.
- Kiss, Anton A.,Dimian, Alexandre C.,Rothenberg, Gadi
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- Iridium-catalysed isomerising trialkylsilylation of methyl oleateq
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Monounsaturated fatty acids from vegetable oils are attractive substrates for applications as renewable feedstock in polymer industry. Applying the concept of transition metal-catalysed isomerising functionalisation, their nearly inaccessible internal C]C double bond can be transformed into products with a functional group in the terminal position. In this work, methyl oleate is shown to undergo [Ir(OMe)( cod)]2-catalysed dehydrogenative silylation with triethylsilane to give terminal vinylsilanes 4 in 69% yield. Independent preparation of reference substances is helpful in identifying the desired products in gas chromatograms of complex reaction mixtures.
- Huber, Thimo,Firlbeck, Doris,Riepl, Herbert M.
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- Palladium-Catalyzed Alkyl-Alkyl Cross-Coupling Reaction of 9-Alkyl-9-BBN Derivatives with Iodoalkanes Possessing β-Hydrogens
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9-Alkyl-9-BBN derivatives undergo the cross-coupling reaction with primary iodoalkanes to give the coupling products in fairly good yields in the presence of a catalytic amount of Pd(PPh3)4 and K3PO4.
- Ishiyama, Tatsuo,Abe, Shigeru,Miyaura, Norio,Suzuki, Akira
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- Enhanced activity over alkyl/aryl functionalized porous pillared-zirconium phosphates in liquid-phase reaction
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A series of porous pillared-zirconium phosphates functionalized with methyl, ethyl, propyl and phenyl groups were prepared and characterized by SEM, 29Si MAS NMR, TG and N2 adsorption. Their total surface acidity and accessible one were measured by potentiometric titration of n-butylamine and liquid phase 2,6-di-tert-butyl-pyridine adsorption, respectively. The catalytic behaviors of these hybrid materials for alkylation of hydroquinone and esterification of lauric acid were compared. Not the total acid sites but the accessible ones play a crucial role in both reactions of alkylation and esterification. The accession for acid sites can be enhanced by the introduction of alkyl/aryl groups, due to the improved hydrophobicity of the surface.
- Liu, Ke,Wang, Xueyan,Ding, Shengda,Li, Ying,Hua, Weiming,Yue, Yinghong,Gao, Zi
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- High-pressure transesterification of sterically hindered esters
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A mild, rapid, and efficient method for the solvolysis of sterically hindered esters under high pressure is described. Transesterification is carried out in the presence of DBU at room temperature and at a pressure of 10 kbar to give quantitative conversions within short reaction times. The substrates examined included aromatic and aliphatic esters of sterically hindered alcohols and phenols. An optically pure benzyl ester of phenylalanine was chosen to study racemization of the amino acid esters under high-pressure reaction conditions.
- Romanski, Jan,Nowak, Piotr,Kosinski, Krzysztof,Jurczak, Janusz
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- Development of an environmentally benign process for the production of fatty acid methyl esters
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The production of fatty acid methyl esters (FAME) is an important intermediate step in oleochemistry. The oleochemical production route starts with the renewable raw materials fat and oil and ends at fatty alcohols and different special products. Fatty acid methyl esters can be formed at mild reaction temperatures by transesterification of natural triglycerides (fats and oils). This contribution will show the development of a continuous process which is considering the main principles of production integrated environmental protection. The main advantages of this process are low energy consumption and minimal waste production. The process alternatives are shown and a scope on future problems which have to be solved to reach a real additional improvement of the fatty acid methyl esters production is given.
- Jordan,Gutsche
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- Mesoporous Ag1(NH4)2PW12O40 heteropolyacids as effective catalysts for the esterification of oleic acid to biodiesel
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Mesoporous Ag1(NH4)2PW12O40 (AgN-PW) was developed by co-doping silver and ammonium ions into phosphotungstic acid as an efficient and stable catalyst for free fatty acid esterification, and its physicochemical properties were derived from X-ray diffraction (XRD), thermogravimetric (TG) analysis, Fourier transform infrared (FT-IR) spectra, N2 adsorption-desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The final catalyst showed a typical Keggin structure of heteropoly acids. This solid acid exhibited remarkable catalytic activity (nearly 100% conversion) in the esterification of oleic acid with methanol for biodiesel production under optimum synthesis conditions. Furthermore, due to the high activity presented in various esterifications of free fatty acids and non-edible oils with high acid values, the mesoporous AgN-PW material was proven to be an environmentally friendly catalyst for industrial biodiesel production.
- Zhang, Qiu-Yun,Wei, Fang-Fang,Li, Qian,Huang, Jin-Shu,Feng, Yun-Mei,Zhang, Yu-Tao
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- Heterogeneous esterification of fatty acids with methanol catalyzed by Lewis acidic organozirconium complexes with Keggin-type mono-aluminum-substituted polyoxotungstates
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Two Lewis acidic organozirconium complexes with α-Keggin-type mono-aluminum-substituted polyoxotungstates, [(n-C4H9)4N]6[α-PW11Al(OH)O39ZrCp2]2 (Cp = η5-C5H5?) (TBA-P-Al-Zr) and [(n-C4H9)4N]6[α-SiW11Al(OH)2O38ZrCp2]2·2H2O (TBA-Si-Al-Zr), were used as heterogeneous catalysts for the esterification of various fatty acids with methanol. For the esterification of linoleic acid at 80 ± 2 °C, TBA-P-Al-Zr exhibited 83% conversion after 6 h, approximately six times higher than that of TBA-Si-Al-Zr. TBA-P-Al-Zr also exhibited 69–90% conversion for the esterification of oleic acid, palmitic acid, myristic acid, and lauric acid with methanol at 80 ± 2 °C.
- Kato, Chika Nozaki,Ogasawara, Tsukasa,Kondo, Akari,Kato, Daichi
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- Quaternary Ammonium Salt Functionalized Methoxypolyethylene Glycols-Supported Phosphotungstic Acid Catalyst for the Esterification of Carboxylic Acids with Alcohols
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The quaternary ammonium salt functionalized methoxypolyethylene glycols-supported phosphotungstic acid catalyst was prepared and characterized using X-ray diffraction, fourier transform infrared spectroscopy and thermogravimetric analysis. The immobilized phosphotungstic acid catalyst exhibited excellent catalytic activity and selectivity, which was shown to be an efficient heterogeneous catalyst for catalyzing the esterification of carboxylic acids with alcohols under mild conditions. The catalyst could be separated by simple separation and can be used six times without significant losing of catalytic activity and selectivity. Graphical Abstract: [Figure not available: see fulltext.]
- Yang, Zhiwang,Zhao, Lei,Lei, Ziqiang
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- Effects of acidity and immiscibility of lactam-based Bronsted-acidic ionic liquids on their catalytic performance for esterification
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Several lactam-based Bronsted-acidic ionic liquids with different acidities were synthesized and applied to the esterification of carboxylic acids with alcohols. High conversion and perfect selectivity were obtained under mild conditions. Among the ionic liquids investigated, those having a methyl sulfonate anion (which has weaker acidity than those with a tetrafluoroborate anion) afforded the highest activity for esterification. The results indicated that the acidity and immiscibility of Bronsted-acidic ionic liquids has a synergistic effect on their esterification performance. Furthermore, after removal of water under vacuum, such ionic liquids could be reused several times without substantial loss of activity.
- Zhou, Hancheng,Yang, Jing,Ye, Linmin,Lin, Haiqiang,Yuan, Youzhu
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- Pyrazinium polyoxometalate tetrakaidecahedron-like crystals esterify oleic acid with equimolar methanol at room temperature
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Ionic-liquid-modified polyoxometalate was prepared by self-assembly of Keggin-type heteropolyacids and sulfonated pyrazinium-IL, in which no template, surfactant, or organic solvent was used. The obtained ionic hybrid exhibits uniform morphology of cubic tetrakaidecahedron-like crystals and possesses a larger number of strong acid sites with narrower dispersion of acid strength than its analogues with similar chemical composition but different morphology. Catalytic activity tests reveal its high conversion, stable recycling, and good substrate compatibility for esterification of free fatty acids (FFA) with methanol into biodiesel at room temperature and over a wide range of molar ratios of methanol to FFA (10-50). Even under the ideal stoichiometric conditions (methanol:FFA = 1:1, a viscous solution), it converts 83% of oleic acid in 24 h. Morphology and performance are discussed, suggesting that the uniform crystals translate into high activity due to improved accessibility of the strong acid sites on the smooth external surface of the catalyst.
- Li, Jing,Li, Difan,Xie, Jingyan,Liu, Yangqing,Guo, Zengjing,Wang, Qian,Lyu, Yinong,Zhou, Yu,Wang, Jun
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- Protic ionic liquids from di- or triamines: even cheaper Br?nsted acidic catalysts
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Dicationic and tricationic ionic liquids, synthesised by proton transfer from sulfuric acid and corresponding di- and triamines, were characterised and used as Br?nsted acidic catalysts in biodiesel production. It has been demonstrated that the new ionic liquids are less expensive than those based on monoamines (even on triethylamine) and are highly acidic. Their performance in a model catalytic esterification reaction surpassed that of sulfuric acid and other literature reports, due to the capability of the ionic liquids to absorb water while phase-separating the ester, thereby shifting the reaction equilibrium towards products. The overall catalytic performance was an interplay between acidity (quantified by Gutmann AN) and physical properties: density and viscosity, which enabled easy phase separation, thereby separating water from the ester. The substrate scope and recycling studies have demonstrated that the new ionic liquids are robust and recyclable catalysts.
- Barteczko, Natalia,Brz?czek-Szafran, Alina,Byrne, Emily,Chrobok, Anna,Kolanowska, Anna,Swad?ba Kwa?ny, Ma?gorzata,Szelwicka, Anna,Wi?c?awik, Justyna
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- Heteropoly acid-encapsulated metal-organic framework as a stable and highly efficient nanocatalyst for esterification reaction
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Metal-organic frameworks (MOFs) have been shown to be promising candidates in the recent decades for the immobilization of guest active species due to their diversified structures, porosity, and high surface area. In this study, silicotungstic acid (HSiW) encapsulated UiO-66 has been successfully synthesized by one-pot synthesis strategy. The synthesized composite (HSiW-UiO-66) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), nitrogen adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric (TG) techniques, and the HSiW-UiO-66 was also employed as a solid acidic catalyst for the synthesis of biodiesel by esterification of lauric acid with methanol. The results revealed that the HSiW-UiO-66 composite had better textural properties (such as large BET surface area (758.3 m2 g-1), large pore volume (0.438 cm3 g-1), and smaller particle size (about 50-200 nm)), good thermal stability, and high catalytic activity. In addition, the effect of the esterification process parameters on biodiesel production was analyzed using single factor experimental method combined with response surface methodology (RSM); a high conversion of 80.5% with single factor optimization and 92.8% with RSM was obtained. More importantly, the conversion of lauric acid decreased from 80.5% to just 70.2% when the catalyst had been reused six times, which exhibited that the catalyst had excellent reusability. The high activity of HSiW-UiO-66 benefited from low activation energy of 27.5 kJ mol-1. This work thus offers an underlying application for green biodiesel obtained from free fatty acids esterification or pre-esterification of low-cost oils with high acid value.
- Zhang, Qiuyun,Yang, Tingting,Liu, Xiaofang,Yue, Caiyan,Ao, Liufang,Deng, Taoli,Zhang, Yutao
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- A new heterogeneous acid catalyst system for esterification of free fatty acids into methyl esters
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A new heterogeneous acid catalyst system for production of environmentally friendly fuel, biodiesel was created from ferric sulfate and non-toxic, inexpensive source of biopolymer, sodium alginate. The catalyst, in the form of ferric-alginate beads produced from the reaction of 2 wt.% sodium alginate gel with 0.1 M ferric sulfate solution gave excellent methyl ester conversion of 98% with mild reaction conditions. The esterification of 0.5 g lauric acid was carried out at optimum conditions; 16 wt.% of ferric-alginate beads (2.8 wt.% Fe) methanol refluxing temperature, 15:1 methanol to lauric acid molar ratio for 3 h. The ferric-alginate beads were reusable up to 7 times without any pre-treatment. Characterization of the ferric-alginate beads showed the formation of FeOOH that held the alginate chain in place. Thermal analysis showed that the beads are able to withstand the refluxing temperature without degradation. Iron content was found to be 0.175 g Fe/g beads as determined by AAS and 0.189 g Fe/g beads as determined by TGA. Easy catalyst separation, reusability and ability of the ferric-alginate beads to esterify lauric acid to give high conversion of methyl laurate makes this catalyst desirable for biodiesel production from high free fatty acid oils.
- Boey, Peng-Lim,Ganesan, Shangeetha,Maniam, Gaanty Pragas,Khairuddean, Melati,Lee, Siew-Ee
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- Predicting reactive equilibria of biodiesel's fatty-acid-methyl-esters compounds
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We present a molecular thermodynamic approach to model the chemical equilibria of biodiesel compounds, i.e., long-chain fatty acid monohydric alcohol esters. Molecules in the reactive system are modeled as chains of spherical segments; van der Waals forces between segments are described by monomer-monomer square-well potentials (SW) whereas associating behavior is introduced via short-ranged attractive anisotropic SW sites. The theoretical framework is based on a non-stoichiometric treatment of the reactive system that uses the minimization of the Helmholtz free energy and a mass balance equation as a restriction. The thermodynamics of the fluid system is obtained from the Statistical Associating Fluid Theory for chain molecules with attractive potentials of variable range (SAFT-VR; A. Gil-Villegas, A. Galindo, P. J. Whitehead, S.J. Mills, G. Jackson, A. N. Burgess, J. Chem. Phys. 106 (1997) 4168-4186). In order to test the accuracy of the theoretical predictions, experimental results were obtained for the esterification of lauric acid with methanol to produce methyl laurate.
- Perdomo, Felipe A.,Millán-Malo, Beatriz M.,Mendoza-Díaz, Guillermo,Gil-Villegas, Alejandro
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- Calcium Hypochlorite-Mediated Oxidation of Primary Alcohols to Methyl Esters
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Primary aliphatic alcohols can be converted to methyl esters using calcium hypochlorite as the oxidant.Primary benzyl alcohols can also be converted efficiently to methyl benzoates.
- McDonald, Chriss E.,Nice, Lois E.,Shaw, Anthony W.,Nestor, Nestor B.
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- Sulfonated porous organic polymer as a highly efficient catalyst for the synthesis of biodiesel at room temperature
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A new functionalized porous organic polymer bearing sulfonic acid groups (PDVTA-SO3H) at the pore surface with high surface area (SBET = 406 m2 g-1) and Bronsted acidity is reported. The material has been synthesized via post-synthetic sulfonation of the porous co-polymer poly-divinylbenzene-co-triallylamine (PDVTA-1) using chlorosulfonic acid as sulfonating agent. A detailed characterization of the -SO3H functionalized porous polymeric material has been carried out using N2 sorption, FT-IR and UV-vis spectroscopy, HR-TEM, FE-SEM, thermogravimetric and elemental analyses. Temperature programmed desorption of NH3 (TPD-NH3 analysis) of PDVTA-SO3H revealed a very high surface acidity of 2.3 mmol g-1. Such high acidity of PDVTA-SO3H has been explored to investigate its catalytic efficiency towards eco-friendly production of biodiesel via esterification of long-chain free fatty acids (FFA) to the respective fatty acid monoalkyl esters (FAMEs) at room temperature using methanol as reactant as well as solvent. The sulfonated porous polymer is found to be a very active and reusable solid acid catalyst giving high yields (~92-98%) of various biodiesel compounds under very mild reaction conditions.
- Gomes, Ruth,Bhanja, Piyali,Bhaumik, Asim
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- The inhibition performance of hydroxy lauric imidazoline for mild steel in chloride solution saturated with CO2
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In the paper, a novel hydroxy lauric imidazoline (HL-IM) was synthesized using lauric acid and ethylene diamine as raw materials. Methanol reaction method was introduced to prepare the hydroxy lauric imidazoline (HL-IM). According to the results of experiments, the optimum synthesis conditions of methanol reaction was determined through orthogonal experiment, which were: methyl laurate: ethylene diamine = 1: 1, sodium methoxide (0.75 wt %), reaction temperature 100°C, reaction time 2 h. The inhibition efficiency of HL-IM inhibitor was investigated in the condition of 5 wt % NaCl solutions saturated with CO2 at 333.15 K for 72 h. With 150 mg L–1 inhibitor dosage, the efficiency of inhibition reached 90.17% by weight loss method. Through film-forming property, foaming characteristic, and emulsification tendency test, it w a s shown that HL-IM had good water-solubility, a smaller emulsification tendency in 5 wt % NaCl solution, and a little foaming performance. Meanwhile, referring to the polarization curves tests, the synergistic effect of HL-IM with the potassium iodide, methylbutynol, and cetyltrimethyl ammonium bromide was studied.
- Ma, Lan,He, Yi,Luo, Pin Ya,Zhan, Yingqing,Yang, Ran Ran,Zhou, Yanqiu
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- An experimental investigation into methyl laureate production via direct esterification of solid fatty acid by using amylum sulfuric acid: An efficient, biodegradable, and recyclable solid acid catalyst
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Recently, many processes have been reported to produce biodiesel via alkali-catalyzed transesterification of triglyceride molecules. However, this requires certain precautions. First, the triglyceride should be nearly pure. Studies show that the presence of water or free fatty acids acts as a poison for the catalyst. Second, the price of pure triglyceride does not allow biodiesel to compete with diesel fuel in cost. These disadvantages are the main reasons why researchers have recently focused on other feedstocks for biodiesel fuel production. Therefore, we investigated the chemical conversion of lauric acid and methanol to methyl laureate fuel via esterification reaction over amylum sulfuric acid as an efficient, biodegradable, and recyclable solid acid catalyst. Synthesized methyl laureate fuel was fittingly characterized by Fourier transform infrared spectroscopy as well as by 1H and 13C nuclear magnetic resonance spectroscopic techniques.
- Savaliya, Mehulkumar L.,Dholakiya, Bharatkumar Z.
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- Isatin based Schiff bases as inhibitors of α-glucosidase: Synthesis, characterization, in vitro evaluation and molecular docking studies
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Isatin base Schiff bases (1-20) were synthesized, characterized by 1H NMR and EI/MS and evaluated for α-glucosidase inhibitory potential. Out of these twenty (20) compounds only six analogs showed potent α-glucosidase inhibitory potential with IC50 value ranging in between 2.2 ± 0.25 and 83.5 ± 1.0 μM when compared with the standard acarbose (IC50 = 840 ± 1.73 μM). Among the series compound 2 having IC50 value (18.3 ± 0.56 μM), 9 (83.5 ± 1.0 μM), 11 (3.3 ± 0.25 μM), 12 (2.2 ± 0.25 μM), 14 (11.8 ± 0.15 μM), and 20 (3.0 ± 0.15 μM) showed excellent inhibitory potential many fold better than the standard acarbose. The binding interactions of these active analogs were confirmed through molecular docking.
- Rahim, Fazal,Malik, Fazal,Ullah, Hayat,Wadood, Abdul,Khan, Fahad,Javid, Muhammad Tariq,Taha, Muhammad,Rehman, Wajid,Ur Rehman, Ashfaq,Khan, Khalid Mohammed
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- Insecticidal compounds against mosquito larvae from Oscillatoria agardhii strain 27
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It was found that Oscillatoria agardhii strain 27 produced compounds toxic against mosquito larvae (Aedes albopictus), therefore, these compounds were extracted and separated for insecticide development. Structural characterization of the toxic fraction by 1H-NMR and GC-MS showed that these compounds are not the neurotoxins or hepatotoxins conventionally produced by Oscillatoria, but it contained a mixture of unsaturated fatty acids, oleic, linoleic, and γ-linolenic acids, as well as saturated fatty acids, myristic, palmitic, and stearic acids. In a bioassay developed for these hydrophobic compounds using mosquito larvae, authentic unsaturated fatty acids were shown to be toxic, whereas saturated ones were active. The results suggested that it might be possible to use unsaturated fatty acids as environmentally safe and effective insecticides without the side effects of the chemically synthesized insecticides. (C) 2000 by John Wiley and Sons, Inc.
- Harada, Ken-Ichi,Suomalainen, Mette,Uchida, Hideaki,Masui, Hiroaki,Ohmura, Kuniyo,Kiviranta, Jari,Niku-Paavola, Marja-Leena,Ikemoto, Takaya
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- Polystyrene-based superacidic solid acid catalyst: Synthesis and its application in biodiesel production
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A polystyrene-supported superacidic fluoroalkyl sulfonic acid catalyst (sPS-S) was synthesized using a combination of iridium-catalyzed C-H borylation and Suzuki-Miyaura coupling reactions. Catalytic activity of the new solid acid catalyst was examined for esterification of fatty acids and transesterification of triglyceride with methanol. Significantly higher activity than those of commercial sulfonated ion-exchange resins (Amberlyst 15 and Nafion NR50) was achieved with a catalyst loading as low as 0.5 wt%. The solid catalyst could be easily recovered by filtration and reused. Consistently high activities were obtained from the esterification for up to ten consecutive runs. This journal is
- Chang, Ying,Lee, Chohee,Bae, Chulsung
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- Tunable aryl imidazolium ionic liquids (TAIILs) as environmentally benign catalysts for the esterification of fatty acids to biodiesel fuel
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Herein, we describe the synthesis of tunable aryl imidazolium ionic liquid catalysts and tested for esterification of fatty acids to biodiesel. In this work, six tunable aryl imidazolium ionic liquids (TAIILs) 1a-1f were prepared. These ionic liquids were used as the economical and reusable catalysts for the synthesis of biodiesel fuels. The reaction has been preceded in a monophase at 80 °C for 4 h, after which the product was separated from the catalyst system by a simple liquid/liquid phase separation at room temperature with excellent yields. With the simple post-process, the catalyst is reusable at least 6 times. This novel method offers a short reaction time, good yields, and environmentally benign characteristics.
- Ho, Wen-Yueh,Lin, Wesley,Lin, Yi-Jyun,Luo, Shun-Yuan,Pantawane, Amit,Su, Po-Fang,Thul, Mayur,Tseng, Shao-An,Wu, Hsin-Ru
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- Novel synthesized microporous ionic polymer applications in transesterification of Jatropha curcas seed oil with short Chain alcohol
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New suites of sulfonic acid-functionalized microporous ionic polymers (PIPs) catalysts were synthesized with polymer, alkyl bromides, and 1, 3-propane sultone via a two-step procedure. The synthesized microporous PIP catalysts were characterized using FT-IR, SEM-Mapping, XPS, N2 adsorption–desorption isotherms, solid NMR spectroscopy, and element analysis. Esterification of several fatty acids with ethanol, which was used as a model reaction in the stabilization of Jatropha curcas seed oil, was checked over functionalized PIP. We tested the catalytic performance of PIP-C8 on the synthesis of fatty acid esters via the transesterification of J. curcas seed oil with a mixture of short-chain alcohols such as ethanol, ethanol–to–diethyl carbonate (1;1 molar ratio), and ethanol–to–dimethyl carbonate (1:1 molar ratio) with 170 mg of PIP-C8 at reflux temperature with agitation. The PIP-C8 catalyst was particularly effective, having achieved yields of 85%, 94%, and 70% for J. curcas seed oil with ethanol, J. curcas seed oil with ethanol–to–DEC, and J. curcas seed oil with ethanol–to–DMC, respectively, under the optimized reaction conditions. The catalyst could be recycled more than five times without significant deactivation. Kinetic studies performed at different temperatures revealed that the conversion of oleic acid to an ethyl ester follows a first-order reaction. The best catalysts with microporous structure (average pore diameter: 1.7–1.9 nm, pore volume: 0.23–0.33 cm3 g–1) and –SO3H density (0.70–0.84 mmol/gcat) were obtained by 1, 3-propane sultone of the chemically activated. The results indicate that the site activity of functionalized microporous ionic polymer materials shows promising approach for the development of environmentally friendly technology.
- Chang, Tao,Hao, Yongjing,Jinxi, Jinxi,Kai, Kai,Panchal, Balaji,Qin, Shenjun,Sun, Yuzhuang,Zhao, Cunling,Zhao, Qiaojing,Zhu, Zheng
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- Hybrid Nanocomposites Formed by Lanthanide Nanoparticles in Zr-MOF for Local Temperature Measurements during Catalytic Reactions
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Zr-metal organic frameworks (MOFs) are water-stable materials with high surface properties and chemical stabilities and are often employed for catalysis. They can also become hosts for various upconverting nanoparticles via self-assembly, which opens up possibilities to use such nanocomposite materials for combined catalysis-thermometry applications. In our work, we show that the NaGdF4:Er,Yb@UiO-66-NH2, NaGdF4:Tm,Yb@UiO-66-NH2, and NaYF4:Er,Yb@NaYF4@UiO-66-NH2 nanocomposite materials display excellent temperature-dependent luminescence properties. Additionally, these nanocomposite materials can perform as a stable and reusable catalyst for the esterification of lauric acid (biomass-derived free fatty acid) with methanol to obtain methyl laurate. The NaGdF4/NaYF4 nanoparticles incorporated in the MOF do not significantly decrease their catalytic performance. At the same time, photoluminescence measurements can be performed in a working catalytic environment and the temperature can be read out from the ratio of the 2H11/2 and 4S3/2 transition peaks of Er3+ or 3F3 and 3H4 transition peaks of Tm3+ from the nanocomposites. The correlation between temperature, luminescent intensities, and catalytic reactivity was studied and showed that all the three factors depend on each other, but do not interfere. To the best of our knowledge, the combination of catalysis and luminescence thermometry in a MOF hybrid material has not been reported to date. However, it opens a wide range of possibilities, keeping in mind the large and versatile number of MOFs as well as different thermometry systems that can be incorporated into inorganic nanoparticles.
- Jena, Himanshu Sekhar,Rijckaert, Hannes,Krishnaraj, Chidharth,Van Driessche, Isabel,Van Der Voort, Pascal,Kaczmarek, Anna M.
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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- Palladium(II) complexes of (pyridyl)imine ligands as catalysts for the methoxycarbonylation of olefins
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Reactions of 2-methoxy-N-((pyridin-2-yl)methylene)ethanamine (L1), 2-((pyridin-2-yl)methyleneamino)ethanol (L2) and 3-methoxy-N-((pyridin-2-yl)methylene)propan-1-amine (L3) ligands with either [PdCl2(COD)] or [PdCl(Me)(COD)] produced the corresponding monometallic complexes [PdCl2(L1)] (1), [PdClMe(L1)] (2), [PdCl2(L2)] (3) and [PdCl2(L3)] (4). The solid state structure of complex 1 confirmed the bidentate coordination mode of L1, giving a distorted square planar geometry. All the complexes (1–4) formed active catalysts for the methoxycarbonylation of higher olefins to give linear and branched esters. The catalytic behavior of complexes 1–4 were influenced by both the complex structure and olefin chain length.
- Zulu, Zethu,Nyamato, George S.,Tshabalala, Thandeka A.,Ojwach, Stephen O.
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- Sulfonic acid modified hollow polymer nanospheres with tunable wall-thickness for improving biodiesel synthesis efficiency
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Precisely designing the morphology and size of nanostructures is vital in green chemistry as various advanced applications depend upon the shapes and dimensions of the functionalised materials. Herein, we report on a green and efficient self-assembly strategy for synthesising hollow polymeric nanospheres with tunable wall thicknesses. The morphology and shell thickness of the nanospheres can be easily tailored by rationally manipulating monomer and catalyst combinations during the one-pot Friedel-Crafts polymerisation process, without using any templates or surfactants. Heterogeneous solid sulfonic acid catalysts can be easily achievedviathe post-sulfonation strategy. These porous materials have preferable surface areas, ordered hollow pore structures, and accessible acidic sites, and they serve as promising catalysts for biodiesel production. This study provides insights into the production of template- and metal-free based catalysts for biofuel production, which is imperative for the green and efficient design and manufacture of high-activity heterogeneous catalysts.
- Kim, Il,Kim, Ji Su,Song, Wenliang,Varyambath, Anuraj,Zhang, Yu
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p. 3572 - 3583
(2020/08/28)
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- Highly ordered mesoporous functionalized pyridinium protic ionic liquids framework as efficient system in esterification reactions for biofuels production
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Polysiloxane acidic ionic liquids containing pyridinium trifluoroacetate salts (PMO-Py-IL) were synthesized from pyridine containing organosilane precursors. Characterization by SEM, XRD, TGA, and nitrogen porosimetry confirmed that both pyridinium cation and trifluoroacetate anion were successfully incorporated within the organosilica network. The resulting organic-inorganic hybrid nanomaterial (PMO-Py-IL) was studied as nanocatalyst in free fatty acids esterification into biodiesel-like compounds. Remarkably, the synergistic hydrophilic/hydrophobic effect of pyridinium and trifluoroacetate ionic liquid in the well-ordered channels of PMO-Py-IL nanomaterial enhanced the activity toward sustainable biodiesel-like esters production. More importantly, PMO-Py-IL nanocatalyst also exhibited an exceptional activity and stability. The catalyst could be easily separated to reuse at least in ten reactions runs preserving almost intact its catalytic activity under otherwise identical conditions to those employed for the fresh catalysts.
- Luque, Rafael,Rajabi, Fatemeh
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- Sulfonated Hyper-cross-linked Porous Polyacetylene Networks as Versatile Heterogeneous Acid Catalysts
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Two highly sulfonated micro/mesoporous polymers, P(1,3-DEB)-SO3H and P(1,4-DEB)-SO3H, with permanent porosity, the specific surface area about 550 m2 ? g?1 and the content of SO3H groups of 2.7 mmol ? g?1 were prepared as new acid Porous Polymer Catalysts, PPCs. The PPCs were achieved by easy sulfonation of parent hyper-cross-linked micro/mesoporous polyacetylene-type networks resulting from a chain-growth homopolymerization of 1,3- and 1,4-diethynylbenzenes. New PPCs are reported as highly active and reusable heterogeneous catalysts of esterification of fatty acids with methanol and ethanol, Prins cyclization of aldehydes with isoprenol and intramolecular Prins cyclization of citronellal to isopulegol. The catalytic activity of the micro/mesoporous PPCs (TON values up to 522 mol ? mol?1) was higher than that of commercial polymer-based heterogeneous catalyst Amberlyst 15 possessing gel texture without permanent pores and that of p-toluenesulfonic acid applied as a homogeneous catalyst.
- Sekerová, Lada,B?ezinová, Pavlína,Do, Thuy Tran,Vysko?ilová, Eli?ka,Krupka, Ji?í,?erveny, Libor,Havelková, Lucie,Bashta, Bogdana,Sedlá?ek, Jan
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p. 1075 - 1084
(2020/01/03)
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- MOFs based on 1D structural sub-domains with Br?nsted acid and redox active sites as effective bi-functional catalysts
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A novel family of lamellar MOF-type materials, which contain Br?nsted acid sites together with redox active centers, based on assembled 1D organic-inorganic nanoribbons were obtained through direct solvothermal synthesis routes, using specific monotopic benzylcarboxylate spacers with thiol substituents in thepara-position like structural modulator compounds and effective post-synthesis oxidized treatments to generate accessible sulfonic groups. Low-dimensional aluminum metal-organic materials, containing free sulfonic pendant groups (Al-ITQ-SO3H), were successfully tested in several acid reactions, such as acetalization, esterification and ring opening of epoxides with a significant impact on fine chemistry processes. The direct introduction of stabilized Pd nanoparticles, cohabitating with pendant sulfonic groups, allowed the preparation of active bi-functional MOF-type hybrid materials (Al-ITQ-SO3H/Pd) capable of carrying out one-pot two-step oxidation-acetalization reactions, exhibiting high yield and high activity during consecutive catalytic cycles.
- Díaz, Urbano,Moreno, José María,Velty, Alexandra
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p. 3572 - 3585
(2020/06/25)
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- Ni-catalyzed direct alcoholysis of N-acylpyrrole-type tertiary amides under mild conditions
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N-Acylpyrrole-type amides are a class of versatile building blocks in asymmetric synthesis. We report that by employing Ni(COD)2/2,2′-bipyridine (5 mol%) catalytic system, the direct, catalytic alcoholysis of N-acylpyrrole-type aromatic and aliphatic amides with both primary and secondary alcohols can be achieved efficiently under very mild conditions (rt, 1 h) even at gram scale. By increasing the catalyst loading to 10 mol%, prolonging reaction time (18 h), and/or elevating reaction temperature to 50 °C/80 °C, the reaction could be extended to both complex and hindered N-acylpyrroles as well as to N-acylpyrazoles, Nacylindoles, and to other (functionalized) primary and secondary alcohols. In all cases, only 1.5 equiv. of alcohol were used. The value of the method has been demonstrated by the racemization-free, catalytic alcoholysis of chiral amides yielded from other asymmetric methodologies.
- Chen, Hang,Chen, Dong-Huang,Huang, Pei-Qiang
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p. 370 - 376
(2020/03/03)
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- Ruthenium-catalyzed hydrogenation of CO2as a route to methyl esters for use as biofuels or fine chemicals
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A novel robust diphosphine-ruthenium(ii) complex has been developed that can efficiently catalyze both the hydrogenation of CO2 to methanol and its in situ condensation with carboxylic acids to form methyl esters; a TON of up to 3260 is achievable for the CO2 to methanol step. Both aromatic and aliphatic carboxylic acids can be transformed to their corresponding methyl esters with high conversion and selectivity (17 aliphatic and 18 aromatic examples). On the basis of a series of experiments, a mechanism has been proposed to account for the various steps involved in the catalytic pathway. More importantly, this approach provides a promising route for using CO2 as a C1 source for the production of biofuels, fine chemicals and methanol.
- Li, Yong,Liu, Qingbin,Ma, Yanping,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Zhang, Qiuyue,Zhao, Ziwei,Zhong, Yanxia
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p. 6766 - 6774
(2020/08/25)
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- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
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Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
- Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
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p. 7526 - 7533
(2020/06/27)
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- Development of small-molecule inhibitors of fatty acyl-AMP and fatty acyl-CoA ligases in Mycobacterium tuberculosis
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Lipid metabolism in Mycobacterium tuberculosis (Mtb) relies on 34 fatty acid adenylating enzymes (FadDs) that can be grouped into two classes: fatty acyl-CoA ligases (FACLs) involved in lipid and cholesterol catabolism and long chain fatty acyl-AMP ligases (FAALs) involved in biosynthesis of the numerous essential and virulence-conferring lipids found in Mtb. The precise biochemical roles of many FACLs remain poorly characterized while the functionally non-redundant FAALs are much better understood. Here we describe the systematic investigation of 5′-O-[N-(alkanoyl)sulfamoyl]adenosine (alkanoyl adenosine monosulfamate, alkanoyl-AMS) analogs as potential multitarget FadD inhibitors for their antitubercular activity and biochemical selectivity towards representative FAAL and FACL enzymes. We identified several potent compounds including 12-azidododecanoyl-AMS 28, 11-phenoxyundecanoyl-AMS 32, and nonyloxyacetyl-AMS 36 with minimum inhibitory concentrations (MICs) against M. tuberculosis ranging from 0.098 to 3.13 μM. Compound 32 was notable for its impressive biochemical selectivity against FAAL28 (apparent Ki = 0.7 μM) versus FACL19 (Ki > 100 μM), and uniform activity against a panel of multidrug and extensively drug-resistant TB strains with MICs ranging from 3.13 to 12.5 μM in minimal (GAST) and rich (7H9) media. The SAR analysis provided valuable insights for further optimization of 32 and also identified limitations to overcome.
- Aldrich, Courtney C.,Baran, Marzena,Boshoff, Helena I. M.,Fu, Peng,Grimes, Kimberly D.,Sibbald, Paul A.,Wilson, Daniel J.
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- Method for synthesis of long-chain fatty acid ester derivative
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The invention relates to a method for synthesis of a long-chain fatty acid ester derivative. Specifically, a hydrochloride of glycine methyl ester or glycine ethyl ester is used as a catalyst to catalyze the esterification reaction of long-chain fatty acid. The method includes: subjecting alcohol and long-chain fatty acid to esterification reaction under the action of the catalyst at certain temperature condition, then conducting extraction and precipitation with ethyl acetate, performing flushing with a sodium chloride aqueous solution for purification. A hydrochloride of glycine methyl esteror glycine ethyl ester is adopted as the catalyst, which belongs to a green catalyst, is the development trend of modern chemistry, has the characteristics of no corrosion to the reaction kettle, lowprice, no toxicity and the like, and is suitable for use as a catalyst to produce palmitate and laurate perfume raw materials.
- -
-
Paragraph 0019-0020
(2020/01/12)
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- Structure determination of fatty acid ester biofuels via in situ cryocrystallisation and single crystal X-ray diffraction
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In situ cryocrystallisation in combination with a zone-melting technique enabled the crystal structure determination of a homologous series of low-melting n-alkyl methyl esters Cn-1H2n+1CO2CH3, from methyl pentanoate (n = 5) to methyl tridecanoate (n = 13), by single crystal X-ray diffraction. Two isostructural groups were identified: the odd-numbered triclinic members (C9,11,13) and the even-numbered orthorhombic members (C8,10,12). All observed structural trends, similarities and differences in intermolecular contacts, including the odd-even effect observable in melting point behaviour and unit cell parameters, were easily visualised and described by 2D fingerprint plots generated from the calculated Hirshfeld surfaces, in combination with atom-atom Coulomb-London-Pauli (AA-CLP) lattice energy calculations.
- Prathapa, Siriyara Jagannatha,Slabbert, Cara,Fernandes, Manuel A.,Lemmerer, Andreas
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- Medium-chain fatty acids from Eugenia winzerlingii leaves causing insect settling deterrent, nematicidal, and phytotoxic effects
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Eugenia winzerlingii (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, Bemisia tabaci and Myzus persicae, on two plant parasitic nematodes, Meloidogyne incognita and Meloidogyne javanica, and phytotoxicity on Lolium perenne and Solanum lycopersicum. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC50 values of 21 and 6 nmol/cm2 for M. persicae and B. tabaci, respectively, and 192 and 64 nmol for M. incognita and M. javanica, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38-52% in root length and 50-60% in leaf length of L. perenne, but no effects were observed on S. lycopersicum. This study highlights the importance of the genus Eugenia as a source of bioactive metabolites for plant pest management.
- Cruz-Estrada, Angel,Ruiz-Sánchez, Esaú,Cristóbal-Alejo, Jairo,González-Coloma, Azucena,Andrés, María Fe,Gamboa-Angulo, Marcela
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- Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
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A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
- Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
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p. 8083 - 8092
(2019/08/26)
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- Aerobic oxidative esterification of primary alcohols over Pd-Au bimetallic catalysts supported on mesoporous silica nanoparticles
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We have prepared a series of mesoporous silica nanoparticle (MSN) supported Pd-Au bimetallic catalysts using a newly developed sequential impregnation method. These catalysts were fully characterized by various techniques including nitrogen sorption, powder X-ray diffraction, inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy (TEM) and high angle annular dark-field scanning transmission electron microscopy (HADDF-STEM). By using this synthetic approach, we observed metal nanoparticles (NP) with diameters of 1–2 nm homogeneously supported on the MSN. The catalytic performance of these MSN supported metal NPs was tested by aerobic oxidative esterification in a tandem reaction where primary alcohols are oxidized to their corresponding aldehydes and to esters in a subsequent reaction. We determined that Pd NPs are very efficient in the first step of oxidation; however, stagnant in the subsequent oxidation. On the contrary, Au NPs show slow reactivity in converting alcohols to aldehydes, but extraordinarily efficient in the oxidation of aldehydes to esters. By fine tuning the metal ratio, the bimetallic catalyst exhibits better reactivity and selectivity toward a variety of primary alcohols than the corresponding monometallic catalysts. In addition, we also found that the bimetallic Pd-Au@MSN catalysts can be recycled three times without a significant loss in activity.
- Tsai, Chih-Hsiang,Xu, Mengze,Kunal, Pranaw,Trewyn, Brian G.
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- Sulfonic acid-functionalized organic knitted porous polyaromatic microspheres as heterogeneous catalysts for biodiesel production
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The use of renewable energy sources decreases the consequences of greenhouse gas emission from fossil fuels. Biodiesel, an easily burning and biodegradable fuel, is an alternative to conventional diesel fuel. The esterification of long-chain fatty acids and transesterification of triglycerides are two major reactions widely used to convert vegetable oils or animal fats into biodiesel. As solid acid catalysts are considered promising candidates for biodiesel production, we have synthesized a series of organic knitted porous polyaromatics (OPPs) using pyrene, anthracene, and naphthalene as monomers via Friedel-Crafts alkylation, followed by crosslinking reactions. The resultant polymers showed good surface morphology, stability and swelling property, high capacity for functionalization due to the unreacted bromomethyl groups on the surface, and excellent hydrophobicity. The sulfonated polymer microspheres obtained by the surface sulfonation showed good surface acidity; thus, they can be employed as heterogeneous solid acid catalysts for the esterification of long-chain fatty acids and transesterification of triglycerides, and they are reusable without any leaching of functional groups.
- Varyambath, Anuraj,Kim, Mi-Ra,Kim, Il
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p. 12745 - 12753
(2018/08/04)
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- Clean and Green Procedure for the Synthesis of Biodiesel from the Esterification of Free Fatty Acids and Alcohol Catalyzed by 6-O-(sulfobutyl)-Β-cyclodextrin
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The catalyst of 6-O-(sulfobutyl)-β-cyclodextrin (SB-CD) is renewable, non-toxic, environmentally benign and biocompatible, which could be used as efficient and recyclable catalyst for the synthesis of biodiesel from free long-chain fatty acids with low-chain alcohols as substrates. The reaction was accomplished at 60°C for 1.5 h, while the products were separated from the catalyst system by liquid/liquid at room temperature with good conversion of 91–98%. The catalyst can be reused for 10 times. The novel and clean procedure offers advantages including short reaction time, good conversion, operational simplicity, and environmentally benign characteristics.
- Zhang, Guangqing,He, Leqin,Yuan, Mingxia,Li, Hui,Chang, Tao,Qin, Shenjun
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p. 1123 - 1128
(2018/10/24)
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- Selective Long-Distance Isomerization of Terminal Alkenes via Nondissociative Chain Walking
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Selective long-distance isomerization of terminal alkenes to silyl enol ethers proceeded via nondissociative chain walking using phenanthroline palladium catalysts. Notable features achieved taking advantage of the nondissociative chain walking mechanism
- Yamasaki, Yuya,Kumagai, Takaaki,Kanno, Shota,Kakiuchi, Fumitoshi,Kochi, Takuya
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p. 9322 - 9333
(2018/07/30)
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- Metal-free transesterification catalyzed by tetramethylammonium methyl carbonate
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Environmentally benign metal-free tetramethylammonium methyl carbonate is effective as a catalyst for the chemoselective, scalable, and reusable transesterification of various esters and alcohols in common organic solvents. In situ-generated highly active species, tetramethylammonium alkoxides, can greatly avoid self-decomposition at ≤110 °C, and are reusable. In particular, chelating substrates, such as amino alcohols, diols, triols, sugar derivatives, alkaloids, α-amino acid esters, etc., which deactivate conventional metal salt catalysts, can be used. A 100 gram scale biodiesel production was also demonstrated.
- Hatano, Manabu,Tabata, Yuji,Yoshida, Yurika,Toh, Kohei,Yamashita, Kenji,Ogura, Yoshihiro,Ishihara, Kazuaki
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supporting information
p. 1193 - 1198
(2018/03/27)
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- Methylation of Aliphatic and Aromatic Carboxylic Acids with Dimethyl Carbonate under the Influence of Manganese and Iron Carbonyls
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The synthesis of methyl esters has been carried out via the reaction of aliphatic and aromatic carboxylic acids with dimethyl carbonate in the presence of manganese and iron carbonyls. The optimal ratio of catalyst and reagents and other conditions for the synthesis of methyl esters of carboxylic acids with high yield have been found.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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- Ni-Catalyzed chemoselective alcoholysis of: N -acyloxazolidinones
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Although N-acyloxazolidinone-based (catalytic) asymmetric synthetic methodologies occupy an important position in modern organic synthesis, the catalytic cleavage of a chiral auxiliary remains underdeveloped. We report the Ni(cod)2/bipyr.-catalyzed alcoholysis of N-acyloxazolidinones to deliver esters. The reaction is broad in scope for both N-acyloxazolidinone substrates and alcohol nucleophiles, and displays good functional group tolerance and excellent chemoselectivity. A gram-scale methanolysis allowed the enantioselective synthesis of the C22-C26 segment of a close analogue of the potent immunosuppressant agent FK506.
- Huang, Pei-Qiang,Geng, Hui
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supporting information
p. 593 - 599
(2018/02/14)
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- Air-Stable α-Diimine Nickel Precatalysts for the Hydrogenation of Hindered, Unactivated Alkenes
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Treatment of a mixture of air-stable nickel(II) bis(octanoate), Ni(O2CC7H15)2, and α-diimine ligand, iPrDI or CyADI (iPrDI = [2,6-iPr2-C6H3N=C(CH3)]2, CyADI = [C6H11N=C(CH3)]2) with pinacolborane (HBPin) generated a highly active catalyst for the hydrogenation of hindered, essentially unfunctionalized alkenes. A range of tri- and tetrasubstituted alkenes was hydrogenated and a benchtop procedure for the hydrogenation of 1-phenyl-1-cyclohexene on a multigram scale was demonstrated and represents an advance in catalyst activity and scope for the nickel-catalyzed hydrogenation of this challenging class of alkenes. Deuteration of 1,2-dimethylindene with the in situ-generated nickel catalyst with iPrDI exclusively furnished the 1,2-syn-d2-dimethylindane. With cyclic trisubstituted alkenes, such as 1-methyl-indene and methylcyclohexene, deuteration with the in situ generated nickel catalyst under 4 atm of D2 produced multiple deuterated isotopologues of the alkanes, signaling chain running processes that are competitive with productive hydrogenation. Stoichiometric studies, titration, and deuterium labeling experiments identified that the borane reagent served the dual role of reducing nickel(II) bis(carboxylate) to the previously reported nickel hydride dimer [(iPrDI)NiH]2 and increasing the observed hydrogenation activity. Performing the catalyst activation procedure with D2 gas and HBPin generated both HD and DBPin, establishing that the borane is involved in H2 activation as judged by 1H and 11B nuclear magnetic resonance spectroscopies.
- Léonard, Nadia G.,Chirik, Paul J.
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p. 342 - 348
(2018/01/17)
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- Efficient flow fischer esterification of carboxylic acids with alcohols using sulfonic acid-functionalized silica as supported catalyst
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Flow Fischer esterification of carboxylic acids using hydroxy-substituted sulfonic acid-functionalized silica (HOSAS) packed into a stainless steel column reactor was investigated. HO-SAS well catalyzed flow esterification of long chain carboxylic acids with methanol within 3min of residence time at 110°C, and the methyl esters were quantitatively obtained. The flow esterification protocol was applied to the synthesis of a variety of esters (19 examples) and scalable synthesis was also successful.
- Furuta, Akihiro,Fukuyama, Takahide,Ryu, Ilhyong
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p. 607 - 612
(2017/06/19)
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- Surfactant-like Br?nsted acidic ionic liquid as an efficient catalyst for selective Mannich reaction and biodiesel production in water
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Abstract: The current study deals with the applications of a surfactant-like Br?nsted acidic ionic liquid (IL) 1-dodecyl-3-methylimidazolium hydrogen sulfate ([DMIm]HSO4) for Mannich reaction at room temperature. The reaction was efficiently preceded in water as solvent without using any harmful and expensive organic additives. Our findings showed that the reaction is selective for cyclohexanone and no Mannich product was observed when cyclopentanone was used as starting material. Density functional theory (DFT) calculations were performed to provide an evidence about the nature of reactivity of the cyclohexanone/cyclopentanone. The activity of the catalyst was also tested for biodiesel production of fatty acids with methanol and ethanol at mild thermal condition without applying additional water removal steps such as using additives or performing special methodologies like azeotropic distillation. In both reactions, the IL can be recycled and reused several times with relatively constant efficiency. Graphical Abstract: [Figure not available: see fulltext.]
- Vafaeezadeh, Majid,Karbalaie-Reza, Mina,Hashemi, Mohammad Mahmoodi,Soleimany, Kasra Qasempour
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p. 907 - 914
(2017/02/26)
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- Development and Application of a Recyclable High-Load Magnetic Co/C Hybrid ROMP-Derived Benzenesulfonyl Chloride Reagent and Utility of Corresponding Analogues
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The development and application of high-load, recyclable magnetic Co/C hybrid ROMP-derived benzenesulfonyl chloride and analogues is reported. The regeneration and utility of these reagents in the methylation/alkylation of various carboxylic acids is demonstrated via efficient retrieval of the magnetic reagent with a neodymium magnet. Additional reactions employing the analogue sulfonic acid and in situ generated magnetic benzenesulfonyl azide are also reported.
- Faisal, Saqib,Zang, Qin,Maity, Pradip K.,Brandhofer, Agnes,Kearney, Patrick C.,Reiser, Oliver,Grass, Robert N.,Stoianova, Diana,Hanson, Paul R.
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supporting information
p. 2274 - 2277
(2017/05/12)
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- Impact of Macroporosity on Catalytic Upgrading of Fast Pyrolysis Bio-Oil by Esterification over Silica Sulfonic Acids
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Fast pyrolysis bio-oils possess unfavorable physicochemical properties and poor stability, in large part, owing to the presence of carboxylic acids, which hinders their use as biofuels. Catalytic esterification offers an atom- and energy-efficient route to upgrade pyrolysis bio-oils. Propyl sulfonic acid (PrSO3H) silicas are active for carboxylic acid esterification but suffer mass-transport limitations for bulky substrates. The incorporation of macropores (200 nm) enhances the activity of mesoporous SBA-15 architectures (post-functionalized by hydrothermal saline-promoted grafting) for the esterification of linear carboxylic acids, with the magnitude of the turnover frequency (TOF) enhancement increasing with carboxylic acid chain length from 5 % (C3) to 110 % (C12). Macroporous–mesoporous PrSO3H/SBA-15 also provides a two-fold TOF enhancement over its mesoporous analogue for the esterification of a real, thermal fast-pyrolysis bio-oil derived from woodchips. The total acid number was reduced by 57 %, as determined by GC×GC–time-of-flight mass spectrometry (GC×GC–ToFMS), which indicated ester and ether formation accompanying the loss of acid, phenolic, aldehyde, and ketone components.
- Manayil, Jinesh C.,Osatiashtiani, Amin,Mendoza, Alvaro,Parlett, Christopher M.A.,Isaacs, Mark A.,Durndell, Lee J.,Michailof, Chrysoula,Heracleous, Eleni,Lappas, Angelos,Lee, Adam F.,Wilson, Karen
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p. 3506 - 3511
(2017/09/15)
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- Synthesis and antimicrobial studies of 5-n-alkyl-1,3,4-oxadiazole-2-thiol derivatives from fatty acids
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The novel 5-N-alkyl-1,3,4-oxadiazole-2-thiol derivatives have been synthesized by esterification of fatty acid followed by reaction the ester with hydrazine hydrate. The acid hydrazide was converted to 1,3,4-oxadiazole by ring closure mechanism. The synthesized compounds have been characterized by physical (melting point and TLC) and spectral (IR, 1H NMR and mass) data. All the compounds were screened for their antimicrobial activity. The compounds 3F1 & 3F4 showed good inhibition activity against all four types of bacteria; while compound 3F2 & 3F3 shown moderate activity.
- Naga Sudha,Yella Subbaiah,Srikanth,Venkata Ramana Reddy,Sneha Latha,Vijaya Lakshmi
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p. 2369 - 2371
(2017/10/31)
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- Lipophilic gold(I) complexes with 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione moieties: synthesis and their cytotoxic and antimicrobial activities
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Novel lipophilic gold(I) complexes containing 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione derivatives were synthesized and characterized by IR, high resolution mass spectrometry, and 1H, 13C 31P NMR. The cytotoxicity of the compounds was evaluated considering cisplatin and/or auranofin as reference in different tumor cell lines: colon cancer (CT26WT), metastatic skin melanoma (B16F10), breast adenocarcinoma (MCF-7), cervical carcinoma (HeLa), glioblastoma (M059?J). Normal human lung fibroblasts (GM07492-A) and kidney normal cell (BHK-21) were also evaluated. The gold(I) complexes were more active than their respective free ligands and cisplatin. Furthermore, antibacterial activity was evaluated against Gram-positive bacteria Staphylococcus aureus ATCC 25213, Staphylococcus epidermidis ATCC 12228 and Gram-negative bacteria Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 27853 and expressed as the minimum inhibitory concentration (MIC). The complexes exhibited lower MIC values when compared to the ligands and chloramphenicol against Gram-positive bacteria and Gram-negative bacteria. Escherichia coli was sensitive one to the action of gold(I) complexes.
- de Almeida, Angelina Maria,de Oliveira, Bruno Assis,de Castro, Pedro P?ssa,de Mendon?a, Camille Carvalho,Furtado, Ricardo Andrade,Nicolella, Heloiza Diniz,da Silva, Vania Lúcia,Diniz, Cláudio Galuppo,Tavares, Denise Crispim,Silva, Heveline,de Almeida, Mauro Vieira
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p. 841 - 857
(2017/10/07)
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- Methylation of mono- and dicarboxylic acids with dimethyl carbonate catalyzed with binder-free zeolite NaY
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Synthesis of methyl mono- and dicarboxylates was developed consisting in treating the corresponding acids with dimethyl carbonate in the presence of a heterogenic catalyst, crystalline aluminosilicate whose mechanically strong granules to 90–95% were built of crystal aggregates of zeolite Y with modulus of about 5.0 in the Na-form. Optimum catalyst and reagents ratio and the reaction conditions were found for the preparation in high yields of methyl esters of mono- and dicarboxylic acids.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Konovalova, Yu. S.,Khazipova,Kutepov
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p. 163 - 168
(2017/04/24)
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- Three new resin glycosides compounds from Argyreia acuta and their α-glucosidase inhibitory activity
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Three new phenolic compounds, acutacoside C (1), acutacoside D (2) and acutacoside E (3) were isolated from the aerial part of Argyreia acuta. The oligosaccharide chain was composed of two glucoses and three rhamnoses, and the aglycone was (11S)-hydroxyhexadecanoic acid (jalapinolic acid). The core of the three compounds was operculinic acid B, which was rare in resin glycosides. Their structures were established by a combination of spectroscopic and chemical methods. Compounds 1-3 have been evaluated for inhibitory activity against α-glucosidase, which all showed weak inhibitory activities.
- Wang, Li,Yan, You-Shao,Cui, Hong-Hua,Yin, Yong-Qin,Pan, Jie-Tao,Yu, Bang-Wei
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supporting information
p. 537 - 542
(2017/01/13)
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- CERAMIDE DERIVATIVES AS ANTICANCER AGENTS
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The invention provides a compound of formula (I): (I) wherein R1-R4 have any of the values defined in the specification, as well as compositions comprising a compound of formula (I) and methods for treating diseases (e.g. cancer).
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Page/Page column 21
(2017/02/09)
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- A magnetically recoverable nanocatalyst based on functionalized mesoporous silica
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A magnetically separable 2D-hexagonally ordered thiol functionalized mesoporous silica material (Fe@TFMS) has been synthesized through co-condensation reaction of 3-mercaptopropyltriethoxysilane (MPTES) and tetraethylorthosilicate (TEOS) using cetyltrimethylammonium bromide (CTAB) as a cationic surfactant followed by immobilization of Fe3O4 nanocrystallies at the functionalized mesopore surface. Powder X-ray diffraction (XRD), N2 adsorption/desorption analysis, FT-IR, TEM, FE-SEM, TGA/DTA, CHNS, XPS and NH3-TPD tools are employed to characterize the materials. This functionalized mesoporous material exhibited high catalytic activity in the biodiesel production from a wide range of long chain fatty acids and soybean oil. The material showed high Lewis acidity of 1.02 mmolg-1 with a good Brunauer-Emmett-Teller (BET) surface area of 411 m2 g-1. Fe@TFMS exhibited excellent catalytic efficiency for this esterification reaction using methanol as a solvent cum reactant under eco-friendly and mild reaction conditions (room temperature, 25 °C).
- Bhanja, Piyali,Sen, Tapas,Bhaumik, Asim
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- Model quinoline-sensitive ionic liquid and its catalytic preparation of long-chain fatty acid a method of esterification of
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The invention discloses a preparation method of a thermo-sensitive ionic liquid and a method for catalyzing a methyl esterification reaction of a long-chain fatty acid by adopting the thermo-sensitive ionic liquid. The structure of the thermo-sensitive ionic liquid is as shown in a general formula (I) and comprises a quinoline cation and anions such as a fluoboric acid radical, a methane sulfonic acid radical and hydrogen sulphate. The preparation method of the thermo-sensitive ionic liquid is mainly characterized in that number of phase states of a system is regulated and controlled by increasing and lowering temperature, namely the system can be in one phase at high temperature and in different phases at room temperature or low temperature after the ionic liquid is rapidly separated from products, so that the whole reaction system guarantees high catalytic efficiency in a homogeneous reaction, separation and recycling are simpler, the disadvantages of limited two-phase catalytic efficiency and difficult recycling of the ionic liquid during homogeneous catalysis are overcome, and a new thought is provided for solving the problems. The general formula (I) is as shown in the specification.
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Paragraph 0072; 0073
(2017/03/14)
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- gSK - 3 beta inhibitor or its salt and its pharmaceutical use
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The invention belongs to the pharmaceutical chemistry field, and discloses a compound for inhibiting glycogen synthase kinase-3beta (GSK-3beta) in a formula I, its pharmaceutically acceptable salt, or an application of its pharmaceutical composition for preventing and treating the GSK-3beta-related diseases. The compound is a GSK-3beta small-molecule inhibitor, its action mode is non-ATP-competitive competition, and can be used for preparing the medicines for preventing and treating the GSK-3beta-related diseases, and the GSK-3beta-related diseases can be diabetes, Alzheimer's disease, stomach cancer, colorectal cancer, pancreas cancer, liver cancer or mixed acute leukemia. According to the compound, R1, R2, R3, X, Y are consistent with detailed description in the invention.
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Paragraph 0084-0087
(2020/02/10)
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- Agent having neurotrophic factor-like activity
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The present invention provides a pharmaceutical agent having high safety and a neurotrophic factor-like activity, which contains, as an active ingredient, any one compound included in fatty acids each having 8 carbon atoms (C8) or having 10 carbon atoms (C10) to 12 carbon atoms (C12) or fatty acid esters thereof, such as 3,7-dimethyloctanoic acid ethyl ester, geranicacidethyl ester, and the like, eachof whichhas 8 carbonatoms (C8), decanoic acid methyl ester, trans-2-decenoic acid, trans-2-decenoic acid methyl ester, trans-2-decenoic acid ethyl ester, trans-2-decenoic acid-2-decenyl ester, trans-2-decenoic acid cyclohexyl ester, trans-2-decenoic acid isopropyl ester, trans-3-decenoic acid methyl ester, trans-9-decenoic acid methyl ester, and the like, each of which has 10 carbon atoms (C10), trans-10-undecenoic acid methyl ester, trans-10-undecenoic acid ethyl ester, and the like, each of which has 11 carbon atoms (C11), and dodecanoic acid, and the like, each of which has 12 carbon atoms (C12), or salts thereof or prodrugs thereof.
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Paragraph 0037-0038
(2016/01/25)
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- A new hypercrosslinked supermicroporous polymer, with scope for sulfonation, and its catalytic potential for the efficient synthesis of biodiesel at room temperature
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We have designed a new hypercrosslinked supermicroporous polymer (HMP-1) with a BET surface area of 913 m2 g-1 by FeCl3via a catalyzed Friedel-Crafts alkylation reaction between carbazole and α,α′-dibromo-p-xylene. Upon sulfonation HMP-1 yielded a very efficient solid acid catalyst for the production of biodiesels via esterification/transesterification of free fatty acids (FFA)/esters at room temperature.
- Bhunia, Subhajit,Banerjee, Biplab,Bhaumik, Asim
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supporting information
p. 5020 - 5023
(2015/03/30)
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- Sulfonic acid-functionalized periodic mesoporous organosilicas in esterification and selective acylation reactions
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The application of sulfonic acid-functionalized periodic mesoporous organosilicas (PMOs) having either phenyl (1a) or ethyl (1b) bridging groups was investigated in the esterification of a variety of alcohols and fatty acids. It was found that 1b consistently exhibited higher catalytic performance than 1a in the described reaction. In particular, it was proposed that the superior catalytic activity of 1b in esterification of fatty acids with methanol is a result of adequate hydrophobic-hydrophilic surface balance in the ethyl PMO catalyst. In addition, the study of chemoselective acylation of 1,3-butanediol with dodecanoic acid with varied mesoporous silica-supported solid sulfonic acids including both 1a and 1b implies that there is a compromise between the reaction selectivity and the surface physicochemical properties of the employed catalyst. Our results clearly show that the catalyst having high surface hydrophilic nature gives high selectivity toward the formation of mono-acylated products whereas those with relatively high hydrophobic characteristics showed enhanced selectivity toward the formation of di-acylated products.
- Karimi, Babak,Mirzaei, Hamid M.,Mobaraki, Akbar,Vali, Hojatollah
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p. 3624 - 3631
(2015/07/01)
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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supporting information
p. 3131 - 3134
(2015/06/17)
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