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A novel polystyrene-supported triol resin was first prepared by reaction of the Merrifield resin with trometamol. Using this resin, arylboronic acids were efficiently isolates and purified through a “capture-release” procedure in organic solvents. However, in basic aqueous solvents arylboronic acids were immobilized on the resin only with low yield.
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The one-pot three-component reaction of arylmethylidenepyruvic acids, 1,3-cyclohexandiones and ammonium acetate provides an economical and efficient synthetic route to 5-oxo-4-aryl-1,4,5,6,7,8-hexahydro-2-quinolinecarboxylic acid 4 under solvent-free conditions using a catalytic amount of TiO2 nanoparticles (TiO2 NPs) as an effective heterogeneous catalyst.
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To study structure-activity relationship of rhodomyrtone against Gram-positive bacteria, structural modification of rhodomyrtone was carried out to afford its 10 analogues. All compounds were assayed for their antibacterial potency using broth microdilution method. The results indicated that rhodomyrtone exhibited higher antibacterial activity against all Gram-positive bacteria than its analogues, with the exception of rhodomyrtone 6,8-diacetate (3) and oxime analogues 6 and 7 which demonstrated similar activity as the parent compound against Bacillus subtilis and Staphylococcus epidermidis with minimum inhibitory concentration and minimum bactericidal concentration ranging from 1 to 4 µg/mL and 2 to 4 µg/mL, respectively. In contrast, all analogues displayed no activity against Acinetobacter baumannii. Hydroxyl and ketone groups of rhodomyrtone were elucidated to be essential for the antibacterial property.
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A series of 8,9-dihydro-2-(2-oxo-2H-chromen-3-yl)-5-aryl-3H-chromeno[2,3-d]pyrimidine-4,6(5H,7H)-diones (5a-j) have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4H-chromene-3-carbonitrile (4a-j) with coumarin-3-catboxylic acid under neat conditions employing Brønsted acidic ionic liquid (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulphate as catalyst. Structures of all the compounds were established on the basis of analytical and spectroscopic data. All the compounds were evaluated for their in vitro antimicrobial activity against different bacterial and fungal strains.
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Two novel N-heterocycle-containing benzotriazole compounds, 5-(5-chloro-2-benzotriazolyl)-6-hydroxy-1,4-dimethyl-3- carbonitrile-2-pyridone (2) and 4-(5-chloro-2-benzotriazolyl)-5-methyl-2-phenyl-3-pyrazolone (4), were synthesized from reactant 4-chloro-2-nitroaniline via diazotization, azo coupling, reductive cyclization and acidification. Their structures were confirmed by FT-IR, 1H NMR, mass spectroscopy and elemental analysis. Their spectral properties were investigated and compared with that of a common commercial benzotriazole UV absorber Tinuvin 326. It is found that the novel N-heterocycle-containing benzotriazole compounds exhibit sharp single peak in the range of 280−400 nm and have much higher molar extinction coefficients than that of Tinuvin 326. Their anti-UV protection properties on polyester fabric were also evaluated and compound 4 was much superior to compound 2 due to its higher exhaustion.
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Ten novel 5-substituted derivatives of 3-(1-hydroxyethylidene)pyrrolidine-2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compounds showed noticeable herbicidal activities, and compounds 6f and 6j exhibited excellent inhibitory activities against the stalk of E. crusgalli, with EC50 values of 94.4 and 72.7 mg/L, respectively.
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One-pot synthesis of substituted pyrano- and furano[3,2-c]quinoline derivatives from appropriately substituted anilines, substituted benzaldehydes and dienophiles via Povarov reaction catalyzed by HCl-ethanol were reported. Good to excellent yields with high diastereoselectivity were obtained in all entries tested.
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In this article, series of novel bi-SO3H-functionalized ILs were synthesized using simple, efficient and economic procedure. Hammett method had been used to determine the acidity order of these ionic liquids, and the acidities of bi-SO3H-functionalized ILs were stronger than that of traditional single-SO3H-functionalized ILs. Their catalytic activities in the synthesis of N-(3-phenyl)-3-oxo-1-phenylpropyl)acetamide were investigated and they were consistent with their acidities.
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Alkynyl selenides were prepared under very mild conditions by reacting terminal alkynes with respective diorganic diselenides in the presence of potassium t-butoxide. The advantages of this protocol include the use of readily available substrates and reagent and good yield of the products.
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The present manuscript describes solid state synthesis of some reported steroidal pyrazolines by a novel eco-friendly route. The synthesized pyrazolines were compared with those obtained from conventional methods in terms of reaction time and overall yield. A substantial enhancement in reaction rate and yield was observed. The antimicrobial activity and the subsequent molecular docking studies of the steroidal pyrazolines have also been carried out.
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The title compound rac-11-t-butoxy-1,4-dihydro-1,4-methanoanthracene (C19H20O, Mr = 264.35) has been synthesized and characterized by FT-IR, 1H NMR, HRMS spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n, with a = 13.5240(10), b = 8.3453(6), c = 13.9604(9) Å, β=100.0190(10)°. The structure of the title compound comprises a norbornene unit with a t-butoxy group, having a naphthalene ring fused on one side. The naphthalene is essentially planar with a maximum deviation of 0.032(2) Å for atom C(3). In the crystal, inversion-related molecules are linked by pairs of C–H...O hydrogen bonds, forming a cyclic dimer with R22(16) graph-set motif. The C–H...π interactions are also observed, linking the molecules into a continuous two-dimensional framework structure.
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A near infrared universal quantitative analysis model was established to determinate the effective ingredient content in pesticide EC (hikernalisation) by the PLS (partial least squares) algorithm, the model predictive ability was evaluated by the external inspection method. The model was established among samples containing the same active ingredient from five different companies, and the model determination coefficient R2 and RMSECV (Root mean square error of cross validation) were 0.9997 and 0.0223 respectively, the relative error between predicted value and chemical value of the testing set samples was between −2.71% and 3.36%, which indicated that the method to determinate the effective ingredient content in pesticide EC by the established universal model can meet the need of pesticide market monitoring .
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To simplify the assessment method of soy protein isolate (SPI) functionalities, the viscosity and functionalities of commercial SPI products were studied. Viscosity value (y) increases with increasing concentration (x) and exhibits a highly significant correlation with the exponential equation y=a•ebx. The b values of products are gradually enhanced from dispersion, emulsion and injected to gel type. Products with low b values (< 0.2), and high dispersivity were dispersion-type. Products having high b values (>0.4) and gel springiness were gel-type. The other products with centered b value (0.2−0.4), high solubility and emulsifying capacity were emulsion-type.
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The determination of enantiomeric composition by partial least squares(PLS) modeling of UV-vis spectral data was investigated for samples of phenylalanine (phe) using sucrose as a chiral auxiliary. And a new data preprocess method, reference band normalization, was introduced to eliminate the spectral variations due to the changes of total concentration of phe. The determination coefficient (R2) and the standard error of calibration set (SEC) of 13 standard samples are 0.9987 and 0.0128 respectively. The standard error of validation set (SECV) of 7 validation samples is 0.0049. The standard error of predict (SEP) of 6 blind samples for evaluating the robustness of the model is 0.0366. The regression model is robust to determine enantiomeric composition when total concentration varied. It is demonstrated that the reference band normalization is a convenient method of compensating for variations in total concentrations without knowing that in advance.
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Influencing atmospheric OH radical budget and tropospheric ozone production, ambient formaldehyde (HCHO) is one of the key oxygenated volatile organic compounds (OVOCs). We present the variations on formaldehyde column densities in summertime in Beijing retrieved from ozone monitoring instrument (OMI) between 2005 and 2011. Satellite columns of HCHO correlated well with available ground-based measurements despite some noticeable differences. The orthogonal distance regression (ODR) method was used to estimate the ratio between satellite columns and ground-level concentrations, whereas ordinary least squares (OLS) method was used to fit the trend of ambient formaldehyde. The formaldehyde concentrations derived from HCHO columns were in the range of 7−12 ppbv and steadily increased at an approximate rate of 0.64 ppbv/yr (7.8% at 2005 level) with an uncertainty of 51%. VOC reactivity quantified by means of OH loss rates showed increasing contribution from formaldehyde and acetaldehyde, rising from 35% in 2005 to 40% in 2010, and decreasing contribution from anthropogenic VOCs, dropping from 49% in 2005 to 40% in 2010. More attention should be paid to understanding the net feedback of increasing formaldehyde to ozone formation potential.
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Three new transition metal complexes have been synthesized with a Schiff base, 3-(2-hydroxy-5-chlorophenylimino)-1,3-diphenylpropen-1-one. In all complexes Schiff base is completely deprotonated and coordinated to metal as tridentate ligand via phenolic and enolic oxygens and imine nitrogen. Thermal decomposition of the complexes has been studied by thermogravimetry. The in vitro antibacterial activity of Schiff bases and their complexes has been evaluated and compared with the standard drugs.
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Non-hygroscopic polystyrene-supported chloroaluminate ionic liquid was prepared from the reaction of Merrifield resin with 1-methylimidazole followed by reaction with aluminium chloride. This Lewis acidic ionic liquid is environmentally friendly heterogeneous catalyst for the Knoevenagel condensation of aromatic and aliphatic aldehydes with ethyl cyanoacetate. The catalyst is stable (as a bench top catalyst) and reusable.
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In this report, a novel thermosensitive poly(N-isopropylacrylamide-co-maleic anhydride-β-cyclodextrin)/(TiO2- multi-walled carbon nanotubes (MWCNTs)) composite (poly(NIPAM-co-MAH-β-CD)/(TiO2-MWCNTs)) was synthesized by UV light photoinitiating method. The results indicated that MAH modified β-CD (MAH-β-CD) could polymerize to NIPAM by UV light irradiation in the presence of TiO2-MWCNTs composite nanoparticles. The characteristic results confirmed that the TiO2-MWCNTs composite nanoparticles were embedded evenly within the thermally responsive copolymer of NIPAM and MAH-β-CD. The effects of irradiation time and TiO2-MWCNTs concentration on the yield of the composites were investigated by keeping NIPAM to MAH-β-CD mass ratio constant. The optimal polymerization reaction conditions were a TiO2-MWCNTs concentration of 10 wt% under UV light for the illumination of 3 h.
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A preceramic polymer, polyzirconosaal (PZSA), was synthesized by the ligand-exchange reaction between polyzirconoxane (PZO) and salicyl alcohol (SA). The precursor was air-stable and exhibited excellent solubility and rheology. These properties are useful for the processing of C/C-ZrC composites via precursor infiltration and pyrolysis (PIP) process. The polymer to ceramic conversion was investigated by TG, XRD and TEM. Nanosized ZrC was formed by pyrolysis of this precursor at 1300 ?C in argon with ceramic yield of 57.8%.
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Bilayer-silane-coated Fe3O4 nanoparticles with inner layer of tetraethoxy silane (TEOS) and outer layer of vinyltriethoxysilane (VTEO) were generated to enhanced their acid resistance. These nanoparticles were copolymerized with vinylbenzyl chloride (VBC) using suspension polymerization, and then post-crosslinked. The resulting hypercrosslinked magnetic resin M150 presented specific bimodal property with large specific surface area of 1109 m2/g. It exhibited more excellent adsorption capacity of p-nitrophenol compared to another two magnetic adsorbents Q150 and MIEX@. Moreover, the acid stable property of the magnetite in M150 extended its application at low pH value.
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One novel difunctionalized polyhedral oligomeric silsesquioxanes (POSS) derivative was designed and synthesized by a convenient method with high yield. 1H NMR and FT-IR characterizations suggested that Michael addition reaction successfully took place between 2-hydroxyethyl acrylate (HEA) and aminopropylisobutyl POSS (POSS-NH2) under mild conditions, which finally formed bi(hydroxyethyl) ester-functionalized POSS derivatives (BH-POSS). Due to the similar functional groups and high reactivity, BH-POSS could be easily incorporated into the main-chain of biodegradable aliphatic-aromatic copolyesters PBTL via in situ melt polycondensation to prepare corresponding degradable nanohybrids with high mechanical properties.
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A new kind of polytriazoleimide contained bisphenyl-1,2,3-triazole (BPT) was synthesized by copper-catalyzed 1,3-dipolar cycloaddition of azides and alkynes (CuAAC) and polycondensation. The thermal stability and degradation mechanism of the polytriazoleimide were investigated. The results show that the structure of BPT in polytriazoleimide transforms to phenylindole after thermal treatment, accompanying the release of N2.
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Uniform CdS colloidal spheres have been successfully synthesized via a simple hydrothermal method. X-ray diffraction (XRD) analyses indicate that the products exhibit a hexagonal structure. Scanning electron (SEM) and transmission electron microscopy (TEM) are used to characterize CdS colloidal spheres. The final size of the spheres may be selected from a range of 71 ± 2 nm to approximately 181 ± 5 nm by changing the amount of polyvinylpyrrolidone (PVP) and hexamethylenetetramine (HMT). The CdS colloidal spheres are not obtained in the absence of either of the capping agents. A synergistic effect between HMT and PVP is proposed to be crucial for the formation of colloidal spheres.
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A novel octazido substituted nanobuilding precursor, octakis[dimethy(p-azidomethylene)siloxyl]octasilsesquioxane (ODA), was prepared by the conventional diazo-transfer reaction of octakis[dimethy(p-chloromethylene)silyl]octasilsesquioxane (ODC) with NaN3, and its structure was characterized by FT-IR, 1H, 13C, 29Si NMR and MALDI-TOF MS, respectively. The structural rearrangement of POSS core in the synthesis strategy of ODA developed in this work was effectively prohibited in comparison with traditionary azidization process. The resultant ODA was not only soluble in common solvents such as CHCl3, THF, toluene, DMF and DMSO, but also could effectively serve as a versatile nanobuilding precursor for the architecture of well-defined organic-inorganic hybrids via click chemistry.
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A fast approach was described for the synthesis of water-dispersible monodisperse dopamine-coated Fe3O4 nanoparticles (DA-Fe3O4 ) with uniform size and shape via ligand-exchange of oleic acid on Fe3O4 using only 2 minutes. The prepared DA-Fe3O4 nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectrometry, and vibrating sample magnetometer. The results indicated that the resulting DA-Fe3O4 nanoparticles had an average diameter of about 19.2 nm. The magnetic saturation value of the prepared DA-Fe3O4 nanoparticles was determined to be 72.87 emu/g, which indicating a well-established superparamagnetic property.
