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When ketones were treated with ammonium chloride and Oxone® in MeOH at room temperature, a direct α-chlorination of ketones was occurred and a series of the corresponding α-chloroketones were obtained in moderate to good yields after 24 hours. In this reaction, ammonium chloride was used as the source of chlorine and Oxone® was used as an oxidant. This method was simple, convenient and providing a novel procedure for preparation of α-chloroketones.
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Lewis acidic ionic liquids were used to catalyze the reaction of epoxypropane with POCl3. Considering the lower cost and catalytic activities, we concluded that [Et3NH]Cl/AlCl3 was the most attractive ionic liquid from an economical point of view. But it would be easily inactivated because of sensitive to water and air. Moreover, it could not be reused easily because of difficulty recovery in the reaction. However, supporting [Et3NH]Cl/AlCl3 catalyst could resolve above problems. Supporting [Et3NH]Cl/AlCl3 catalyst could be separated by filter easily and reused 5 times in 98% yield. Furthermore, the catalyst was applicable to other epoxy ether cleaving reactions.
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A convenient solvent less cyclocondensation from thiosemicarbazone of benzofuranone and chloroacetic acid using an ionic liquid, N-methylpyridinium tosylate for obtaining novel 4-thiazolidinones in excellent yields is reported. Also, the green expedient synthesis of new 2,4-disubstituted thiazoles under grinding condition from phenacyl bromides and thiosemicarbazide derivatives in quantitative yields is reported.
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A novel and efficient route for the synthesis of 1,8-dioxooctahydroxanthenes and 14-aryl-14H-dibenzo[a,j]xanthenes is described through one-pot multi-component reaction of dimedone and 2-naphthol with various aryl aldehydes using ZnO nanoparticles under solvent-free conditions. This method provides a novel and improved pathway for the synthesis of xanthenes in the terms of excellent yields, short reaction times, reusability and low catalyst loading.
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A new class of 3-phenyl 4-substituted-β-carbolines via iodine-mediated electrophilic cyclization as key step were synthesized and their inhibitory activity against three tumor cell lines was evaluated in vitro. It was found that some of the tested compounds showed better cytotoxicity against HeLa and MCF-7 cells than harmine.
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A series of novel N-tert-butyl-N'-acyl-5-methyl-1,2,3-thiadiazole-4-carbohydrazides were designed and synthesized. Their structures were characterized by melting points, 1H NMR, IR, ESI-MS, and elemental analysis. The bioassay tests indicated that compound 7o exhibited excellent direct anti-TMV activity and induction activity in vivo at 50 μg/mL, which was better than that of Ninamycin and tiadinial. Our studies indicated that 1,2,3-thiadiazole was an active substructure for novel pesticide development.
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Straight-chain aliphatic tert-amine N-oxides was found to be useful oxidizing agent for epoxidation of tri- and tetra-substituted perfluoroalkenes under mild conditions in high yields. The process for epoxidation by employing tri-n-butylamine N-oxide gave the best result in the reagent survey.
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Two new phenylpropanoid glycosides, 9-O-[6-O-acetyl-β-D-glucopyranosyl]-4-hydroxycinnamic acid (1) and 8-O-β-D- glucopyranosyl-(R)-(+)-3,4,8-trihydroxy methyl phenylpropionate (2) were isolated from the 80% EtOH extract of the roots of Sanguisorba officinalis. Their structures were characterized by spectroscopic analysis and chemical method, including 1D NMR, 2D NMR, and HR-ESI-MS. Compounds 1 and 2 exhibited the moderate antimicrobial activities against all Gram-positive and Gram-negative bacteria tested.
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Two new unsaturated alkylamides (2E,7E,9E)-N-(2-hydroxy-2-methylpropyl)-6,11-dioxo-2,7,9-dodecatrienamide (1) and (2E,6E,8E)-N-(2-hydroxy-2-methylpropyl)-10-oxo-2,6,8-decatrienamide (2) together with six known compounds (3−8) have been isolated from the pericarps of Zanthoxylum bungeanum. Their structures were elucidated on the basis of extensive spectroscopic analysis, including MS, IR, 1D and 2D NMR experiments.
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One new and 16 known compounds were isolated from Abies sibirica. Their structures were assigned mainly on the basis of NMR and MS spectroscopic data. In bioassay for anti-proliferative activity against four human tumor cells, compound 7 exhibited selective anti-proliferative activity against COLO-205 tumor cell with an IC50 value of 0.9 μg/mL.
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The mechanism for synthesis of 4,4-methylenedianiline (MDA) via condensation reaction of aniline with formaldehyde has been studied extensively in this paper. The intermediate and by-products were isolated and identified. The combination of isotope labeling and HPLC-MS characterizations disclosed that the reaction proceeded through an SN2 reaction mechanism. Moreover, the effect of aniline/formaldehyde molar ratio on the formation of MDA was investigated. This work would be of significance to understand the reaction mechanism deeply and provide valuable information for further improving the yield of desired product.
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A new β-cyclodextrin modified hyperbranched carbosilane stationary phase for gas chromatography was synthesized by substituting the -OH groups of β-cyclodextrin with hyperbranched carbosilane and was coated on the inner wall of fused silica capillary column for gas chromatography. The chromatographic behaviors of the stationary phase were studied. The initial testing results showed that it possessed good separation abilities for several kinds of mixtures, such as benzenes, acrylates, ketones and alkylchlorides.
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A new and simple method was developed to determine anions in oxalate of analytical reagent grade. After UV photolysis with optimal 1% H2O2 in 10000 mg/L oxalate in the fabricated photoreactor, sample was directly injected into IC system. Satisfactory linearity, detections limits, good repeatability and spiked recovery were obtained. The method was successfully applied to determine anions in two commercial oxalate samples.
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A novel magnetic weak acid resin NDMC-1 was prepared in the presence of methyl acrylate (MA), divinylbenzene (DVB) and titanate coupling agent (TCA) coated γ-Fe2O3 particles. To evaluate the adsorption of Cu2+ on the obtained resin NDMC-1, another two magnetic resins NDMC-0 (the precursor of NDMC-1 without hydrolyzation) and NDMO-1 (the synthesized weak acid resin using oleic acid coated γ-Fe2O3 ) were chosen for comparison. The results showed that the carboxyl groups were formed after hydrolyzation, and NDMC-1 exhibited a greater adsorption capacity to Cu2+. The desorption experiment demonstrated that the desorption ratio at pH 2 (95.14%) was greatly higher than pH 3 (25.97%). Moreover, the magnetic resin NDMC-1 was proved to be stable at pH 2, extending the application of magnetic materials which were always considered to be acid-nonresistant.
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A new procedure based on generation and subsequent reduction of orange-colored fluphenazine hydrochloride radical (FPH•+) is presented for the screening of total antioxidant capacity (TAC) of various fruit matrices. The FPH•+ was obtained by mixing fluphenazine hydrochloride with persulfate (final concentration 2 mmol/L and 0.05 mmol/L, respectively) in 3 mol/L H2SO4 with constant shaking for five minutes. The solution formed showed maximum absorption as 0.8 ± 0.02 at 500 nm in first-order derivative spectrum. The percent inhibition of the solution increased linearly on addition of increasing amounts of standard antioxidants i.e., ascorbic acid etc. The TACs of sample citrus juices were calculated in terms of ascorbic acid equivalents (AAEs) by comparing their inhibition curves with that of ascorbic acid. Comparison of AAE values of different commercial orange juices using the newly developed FPH•+ assay and the well-known ABTS/K2S2O8 and DMPD/FeCl3 assays indicated the precision and comparable sensitivity of the method. The proposed procedure is quick, economical, and more precise and gives results comparable to contemporary assays.
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Nitrous oxide adsorption on the pristine (6,0) magnesium oxide nanotube was studied by using density functional theory calculations. We present the nature of the N2O interaction in selected sites of the nanotube. Adsorption energies corresponding to adsorption of the N2O on the nanotube were calculated to be in the range -11.67 to –22.21 kJ mol-1. Our results indicate that the N2O molecule has a weak physical adsorption on the pristine models due to weak Vander Waals interaction between the nanotubes and N2O molecule. The important results can be useful in production of the N2O sensors.
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A series of salicylideneaniline derivatives 1a-1f were synthesized under mild condition in high yields, and characterized by 1H NMR, HRMS, UV-vis and emission spectra. In solid and aprotic solvents 1a-1f exist mainly as E conformers that possess a six-membered-ring hydrogen bond and undergo excited-state intramolecular proton transfer (ESIPT) reactions, resulting in a proton-transfer tautomer emission. Depending on the electronic donor or acceptor strength of the substituent in either the HOMO or LUMO site, a broad tuning range of the emission from green (1c) to red (1a) has been achieved.
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The interaction between [Hg(SCN)4]2− and hemoglobin (Hb) under conditions that simulate a physiological environment was investigated by UV-vis spectroscopy, ?uorescence spectroscopy, resonance Rayleigh scattering (RRS) spectroscopy and circular dichroism (CD) spectroscopy. The results obtained from the change of UV-vis and CD spectra, the quenching of Hb ?uorescence and the enhancement of RRS intensity proved that a 10:1 type complex was formed between [Hg(SCN)4]2− and Hb. The possible mechanism suggested for the interaction was that ten Hg(SCN)4]2− anions entered the four subunits of a Hb molecule to react with some residues to form an adduct by coordination and electrostatic forces. The coordination of [Hg(SCN)4]2− with Trp was the major cause of the ?uorescence quenching of Hb.
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Flooded soil samples were collected in the typical area of the Yangtze Delta Region, fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption spectrometry. In flooded soils, fractions of heavy metals increased in the order of acid soluble < oxidisable < reducible < residual. The acid soluble and reducible fractions significantly decreased but residual fraction significantly increased when the samples were air dried. The data obtained from air dried soil samples could not accurately represent the speciation of heavy metals in flooded field conditions.
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A new type of sample cell specially designed for micro-Raman spectrum study on volatile melts is described. The cell is made of quartz. The lower section of the cell is circular ring-shaped and the one-end-closed hole in the cell is used for locating the heating body. The tube attached to the cell lid for placing the thermal couple is inserted into the sample, which ensures that the temperature measurement accuracy is good. The cell can be sealed for reducing the effect of the composition change caused by the inhomogeneous volatilization. During the Raman spectra scanning, the laser beam is transmitted into the cell through the side but not the top. Meanwhile, a furnace has been designed to match the cell. The heating body is closely coupled with the sample cell, and there is a hole on the side wall of the furnace for the entrance of the microlens. The assembly has performed well in the tested Raman spectrum measurement of molten NaNO3 at 602 ℃.
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New experimental data of densities and surface tensions are presented for the binary mixtures of the ionic liquid 1-ethyl-3-methyl imidazolium nitrate ([EMIM]NO3) with methanol and ethanol. Measurements were performed at 298.15 K and atmospheric pressure, covering the whole composition range. Excess molar volumes VE and the surface tension deviations δγ have been determined. For the excess molar volumes of binary mixture, there is a region of negative VE at low IL mole fraction, passing through a minimum and then VE increases and becomes positive, showing maximum at higher IL mole fraction. It is shown that the surface tension deviations δγ of [EMIM]NO3+methanol system are positive but those of [EMIM]NO3+ethanol system are negative over the entire mole fraction range.
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Erbium-doped lutetia nanopowders were synthesized by a novel co-precipitation method using tartaric acid as precipitant. The properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), TG-DSC, field emission scanning electron microscopy (FE-SEM), and upconversion luminescence analysis. Pure cubic Lu2O3 nanopowders were directly obtained when the precursor was calcined at 800 °C for 2 h, the samples showed strong upconversion luminescence under excitation of 980 nm laser diode.
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A series of poly(arylenethynylene)s containing dibenzosilole unit has been synthesized by palladium-catalyzed Sonogashira cross-coupling reactions with 2,7-diethynyl-9,9-dihexyl-3,6-dimethoxy-9H-dibenzosilole (4) as the key monomer. Their photo- physical properties in solution were investigated. All of the polymers showed intense fluorescence with high quantum efficiencies.
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A novel bifunctional comonomer 3-ammoniumcarboxylate-butenoic acid-methyl ester (ACBM) was synthesized for preparing poly[acrylonitrile-co-(3-ammoniumcarboxylate-butenoic acid-methyl ester)] [P(AN-co-ACBM)] copolymer as a carbon fiber precursor. Differential scanning calorimetry results show that the P(AN-co-ACBM) exhibits a significantly improved stabilization performance compared with polyacrylonitrile (PAN), such as lower cyclization temperature and smaller rate of heat release, which is mainly attributed to the initiation of ACBM through an ionic cyclization mechanism. Simultaneously, the rheological analysis show that P(AN-co-ACBM) possesses better spinnability than PAN.
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Electrochemical synthesis of poly(2,6-pyridinediamine) (PPa) in aqueous sodium hydroxide solution has been carried out by using cyclic voltammetry for the first time. The scanning electron microscopy (SEM) revealed the interpenetrating network structure of the as-prepared PPa film, which makes it possible that anions can be doped into the polymer in the oxidation process, and vice versa in the reduction process. The results from FT-IR spectrum provided a possible polymerization mechanism of 2,6-pyridinediamine.
