Article ID 0026 April 2019
The sequential Michael addition/retro-Claisen condensation of 1,3-diarylpropan-1,3-diones with nitrostyrenes is described. 4-Nitro-1,3-diarylbutan-1-ones were efficiently synthesized in good to high yield under mild, transition-metal-free condition. This one-step method involving sequential carbon-carbon bond formation and cleavage provides a good alternative to the synthesis of various γ-nitro ketones.
Article ID 0027 April 2019
A small library of diverse 1,1-diaryl-2-(1,2,3)triazol-1-yl-ethanol derivatives was designed and prepared from CuAAC reaction as the key step. The molecular structure of some representative compounds was unambiguously determined from X-ray diffraction studies. In addition, synthesized 1,2,3-triazoles wereevaluated for activity against filamentous fungi (Mucor hiemalis, Aspergillus fumigatus, Trichosporon cutaneum, and Rhizopus oryzae) and yeasts that belong to the genus Candida. Two compounds showed high activity against C. utilis (MIC 0.5 μg/mL) and A. fumigatus (MIC 4 μg/mL) which is close to itraconazole used as reference compound.
Article ID 0028 April 2019
An electrochemical sensor for hydrogen peroxide (H2O2) detection was established using 1-aminopyrene (AP) as a linker between horseradish peroxidase (HRP) and reduced graphene oxides (rGO) modified glassy carbon electrode. The AP can combine with HRP via a covalent bond and combine withrGO via π-π conjugation. The covalent bond linkages can prevent the enzymes leaching of the enzymes and the π-π conjugate combination can facilitate electrons transfer, which plays synergistic effects to improve the performance of this sensor. The electrochemical activity of the HRP-AP/rGO was described by cyclic voltammetry, alternating current impedance and amperometric techniques. Under the optimal conditions, the biosensor showed a wide linear range from 1.5 μM to 28.5 μM and a low detection limit of 0.5 μM with good stability and high selectivity, confirming that the sensor is well-suited for the detection of H2O2 during biological processes.
Article ID 0029 April 2019
An efﬁcient synthesis of a series of pyrazolopyridocoumarins is reported by condensation of 4hydroxycoumarin, benzaldehydes and 1-alkyl-5-amino-pyrazoles in the presence of 10 mol% zinc chloride in ethanol under reﬂux conditions through one-pot reaction. The signiﬁcant attraction of this protocol is being a simple procedure, mild reaction condition, and excellent yield. The molecular structure of the compound (4e) is established by single crystal X-ray structure determination.
Article ID 0030 April 2019
In this study, 4,7-dihydrotetrazolo[1,5-a]pyrimidine derivatives (1–5) were prepared via Multicomponent Cyclocondensation Reactions(MCRs). All structures were determinedbyusingFT-IR,1H/13CNMR and elementalanalyses. The compounds were investigated as corrosion inhibitors using density functional theory (DFT) at the level of B3LYP/6-31G (d, p). According to the calculations, compound 1 appears to be a good inhibitor for corrosion. In addition, the electrochemical properties of the novel systems were investigated by CV.
Article ID 0031 April 2019
We investigate the role of the length scale of attraction on the dynamical heterogeneity in three dimensional core-softened (CS) model liquid having interaction potential of two different length scales. Using the simple CSmodel, we have shown that the presence of heterogeneity is attributed to the existence of attractive interactions in a system.The timescale associated with the peakposition of the non-Gaussian parameter is found to be strongly dependent on the temperature for different length scale of attraction.The dynamical heterogeneity dramatically decreases with the increase in temperature. We further characterize dynamical heterogeneity by calculating newnon-Gaussian parameter which indicates the existence of much longer relaxation timescale than that suggested by the peak position in the non-Gaussian parameter. Furthermore, we have shown the presence of particles, whose displacement distribution deviates from the Gaussian distribution and contributes towards the origin/presence of heterogeneity.
Article ID 0032 April 2019
Two novel tridentate SNS pincer type ligands, 2,6-bis[[(2'-methoxyphenyl)thio]methyl]pyridine (L1) and 2,6-bis[[(2'-chlorophenyl)thio]methyl]pyridine (L2), each possessing two sulfur and one nitrogen donor functionalities (SNS), based on 2,6-bis(thioether)pyridine ligands were prepared and metallised with CuCl2 · 2H2O and FeCl2 · 4H2O metal salts. Two new unanticipated complexes were obtained from the L,2 ligand, the dimeric bidentate Cu(I) complex [Cu2(κ2−L2)2Cl2] and tridentate Fe(II) complex [Fe(κ3−L2)Cl2] while two new tridentate pincer-type complexes M(κ3-L1)Cl2] (M = Cu, Fe) were formed from the L1 ligand It was observed that the structure of this Cu(I) complex has a tetrahedral geometry using single crystal Xray diffraction analysis. In addition, catalytic properties of metal complexes towards the formation of cyclic carbonates from CO2 and epoxides were investigated. The less sterically hindered Fe(II) complex with theL1 ligand [Fe(κ3−L1)Cl2] (2) showed the best catalytic activity. Several parameters including temperature, time, epoxide identity and CO2 pressure were investigated to find the optimum catalytic reaction conditions. Moreover, DFT studies of these compounds are presented in the study.
Article ID 0033 April 2019
A range of commercially produced TiO2 was deposited with Pd nanoparticles and the activities of the anaerobic, ambient temperature photocatalytic hydrogen production from water-methanol mixture were evaluated. The photocatalytic reactions were carried out in the liquid and gas phase conditions with the rate ofhydrogen evolutions were higher was when in the gas phase. The Pd/TiO2 catalysts were characterised using XRD, N2 adsorption, infrared and XPS in order to investigate the influence of structural properties of TiO2 in determining photocatalytic activity. A positive relationship was established in the rate of hydrogen production from the gas and liquid phase conditions with the size of crystallite TiO2. Analysis of the surface properties of TiO2 using XPS shows the presence of surface hydroxyl that also influenced the photocatalytic activity of TiO2.
Article ID 0034 April 2019
In this paper, we explore the catalytic activity of SiO2 nanoparticles (NPs) as an eco-friendly, efﬁcient and reusable catalyst in the synthesis of 2,3-dihydro-1H-perimidines as well as tetraketones. For tetraketones syntheses, a simple tandem Knoevenagel condensation following Michael addition procedure is performed by the reaction between benzaldehydes and 5,5-dimethyl-1,3-cyclohexanediones under solvent-free condition using SiO2 NPs as an efﬁcient solid catalyst. In addition, for 2,3-dihydro-1H-perimidines syntheses, cyclocondensation of various aldehydes with 1,8-diaminonaphthalene is achieved under solvent-free condition using SiO2 NPs as a catalyst at room temperature. The results showed catalytic enhancement in both synthetic procedures.In this work,4-(2,3-dihydro-1H-perimidin-2-yl)benzonitrileand2-(pyridin-4-yl)-2,3-dihydro-1Hperimidine are synthesized as new compounds. Also, reusability study of SiO2 NPs was done to ensure its applicability as a recycled catalyst in this work.