InCl3 catalyzed carbene insertion into O-H bonds: efficient synthesis of ethers

An efficient InCl₃ mediated insertion of the carbene fragment (:CHCO₂Et), generated in situ from ethyl diazoacetate into O-H bond of a series of saturated and unsaturated alcohols under mild conditions has been developed to afford the corresponding ethers as exclusive products in good to high yields (70-95%) and in shorter reaction times. In the case of unsaturated alcohols, the reaction proceeded with unprecedented selectivity resulting in ethers as the only products and in high yields.     

Functionalization of mesoporous carbon with superbasic MgO nanoparticles for the efficient synthesis of sulfinamides

Highly basic MgO nanoparticles with different sizes have been successfully immobilized over mesoporous carbon with different pore diameters by a simple wet-impregnation method. The prepared catalysts have been characterized by various sophisticated techniques, such as XRD, nitrogen adsorption, electron energy loss spectroscopy, high-resolution TEM, X-ray photoelectron spectroscopy, and the temperature-programmed desorption of CO(2). XRD results reveal that the mesostructure of the support is retained even after the huge loading of MgO nanoparticles inside the mesochannels of the support. It is also demonstrated that the particle size and dispersion of the MgO nanoparticles on the support can be finely controlled by the simple adjustment of the textural parameters of the supports. Among the support materials studied, mesoporous carbon with the largest pore diameter and large pore volume offered highly crystalline small-size cubic-phase MgO nanoparticles with a high dispersion. The basicity of the MgO-supported mesoporous carbons can also be controlled by simply changing the loading of the MgO and the pore diameter of the support. These materials have been employed as heterogeneous catalysts for the first time in the selective synthesis of sulfinamides. Among the catalysts investigated, the support with the large pore diameter and high loading of MgO showed the highest activity with an excellent yield of sulfinamides. The catalyst also showed much higher activity than the pristine MgO nanoparticles. The effects of the reaction parameters, including the solvents and reaction temperature, and textural parameters of the supports in the activity of the catalyst have also been demonstrated. Most importantly, the catalyst was found to be highly stable, showing excellent activity even after the third cycle of reaction.     

Magnetic and electrical behavior of La1−xAxMnO3 (A=Li, Na, K and Rb) manganites

With a view to understand the magnetic and electrical behavior of monovalent substituted lanthanum manganites, a series of materials were prepared by sol-gel route by sintering at 1200 °C. The X-ray diffraction data were analyzed using Rietveld refinement technique and it has been found that all the samples were found to crystallize into rhombohedral structure with R3¯c space group. The values of ferro to paramagnetic (T_C) and metal-insulator transition (T_P) temperatures were obtained using ac susceptibility and electrical resistivity data, respectively. It has been found that sodium-, potassium- and rubidium-doped samples exhibit two peaks in the electrical resistivity vs. temperature plots. The observed behavior has been explained on the basis of oxygen deficiency present in the samples. The electrical resistivity data were analyzed using various theoretical models and it has been concluded that the electrical resistivity data in the low-temperature regime (T<T_P) can be explained using the equation ρ_(T)=ρ₀+ρ₂T²+ρ_4.5T^4.5, signifying the importance of the grain/domain boundary, electron-electron and two magnon scattering processes. On the other hand, the high-temperature resisitivity data (T>T_P) were explained using variable range and small polaron hopping mechanisms.     

Spin-alignment and g-factor measurement of the I^{\pi} = 12+ isomer in 192Pb produced in the relativistic-energy fragmentation of a 238U beam

Reactions of a 16.8 MeV ⁶He beam with a ⁹Be target have been investigated using highly segmented detector setup covering a large solid angle. Data on elastic and quasi-free scattering, as well as two-neutron transfer, are reported. The results for elastic scattering are fairly well reproduced by a CDCC calculation, in agreement with the interpretation of a breakup effect already observed for the scattering of ⁶He on other light targets. Exotic quasi-free scattering of ⁶He on $ \alpha$ -cluster in ⁹Be is clearly observed. Inclusive and coincident events were used to extract information on the two-neutron transfer reaction ⁹Be(⁶He, $ \alpha$ )¹¹Be . Sequential decay of the ¹¹Be state at the excitation energy $\ensuremath E_x = 10.6$ MeV through different channels is discussed.     

A systematic literature review of Burgers’ equation with recent advances

Even if numerical simulation of the Burgers’ equation is well documented in the literature, a detailed literature survey indicates that gaps still exist for comparative discussion regarding the physical and mathematical significance of the Burgers’ equation. Recently, an increasing interest has been developed within the scientific community, for studying non-linear convective–diffusive partial differential equations partly due to the tremendous improvement in computational capacity. Burgers’ equation whose exact solution is well known, is one of the famous non-linear partial differential equations which is suitable for the analysis of various important areas. A brief historical review of not only the mathematical, but also the physical significance of the solution of Burgers’ equation is presented, emphasising current research strategies, and the challenges that remain regarding the accuracy, stability and convergence of various schemes are discussed. One of the objectives of this paper is to discuss the recent developments in mathematical modelling of Burgers’ equation and thus open doors for improvement. No claim is made that the content of the paper is new. However, it is a sincere effort to outline the physical and mathematical importance of Burgers’ equation in the most simplified ways. We throw some light on the plethora of challenges which need to be overcome in the research areas and give motivation for the next breakthrough to take place in a numerical simulation of ordinary / partial differential equations.     

In Silico Molecular Docking Analysis of Karanjin against Alzheimer’s and Parkinson’s Diseases as a Potential Natural Lead Molecule for New Drug Design,Development and Therapy

Parkinson’s disease (PD) and Alzheimer’s disease (AD) are neurodegenerative disorders that have emerged as among the serious health problems of the 21st century. The medications currently available to treat AD and PD have limited efficacy and are associated with side effects. Natural products are one of the most vital and conservative sources of medicines for treating neurological problems. Karanjin is a furanoflavonoid, isolated mainly from Pongamia pinnata with several medicinal plants, and has been reported for numerous health benefits. However, the effect of karanjin on AD and PD has not yet been systematically investigated. To evaluate the neuroprotective effect of karanjin, extensive in silico studies starting with molecular docking against five putative targets for AD and four targets for PD were conducted. The findings were compared with three standard drugs using Auto Dock 4.1 and Molegro Virtual Docker software. Additionally, the physiochemical properties (Lipinski rule of five), drug-likeness and parameters including absorption, distribution, metabolism, elimination and toxicity (ADMET) profiles of karanjin were also studied. The molecular dynamics (MD) simulations were performed with two selective karanjin docking complexes to analyze the dynamic behaviors and binding free energy at 100 ns time scale. In addition, frontier molecular orbitals (FMOs) and density-functional theory (DFT) were also investigated from computational quantum mechanism perspectives using the Avogadro-ORCA 1.2.0 platform. Karanjin complies with all five of Lipinski’s drug-likeness rules with suitable ADMET profiles for therapeutic use. The docking scores (kcal/mol) showed comparatively higher potency against AD and PD associated targets than currently used standard drugs. Overall, the potential binding affinity from molecular docking, static thermodynamics feature from MD-simulation and other multiparametric drug-ability profiles suggest that karanjin could be considered as a suitable therapeutic lead for AD and PD treatment. Furthermore, the present results were strongly correlated with the earlier study on karanjin in an Alzheimer’s animal model. However, necessary in vivo studies, clinical trials, bioavailability, permeability and safe dose administration, etc. must be required to use karanjin as a potential drug against AD and PD treatment, where the in silico results are more helpful to accelerate the drug development.     

Application of Almost Increasing Sequence for Absolute Riesz $|\overline{N}, p_n^{\alpha, \beta}; \delta|_k$ Summable Factor

In this paper, we generate an extended result by Bor and Seyhan concerning absolute Riesz summability factors. Further, we develop some well-known results from our main result.     

Sulphonated poly(ether ether ketone): synthesis and characterisation

The paper describes the sulphonation of commercially available poly(ether ether ketone) PEEK (GATONE^TM, Gharda Chemicals Limited, India and VICTREX^®, ICI Limited, UK) by using concentrated sulphuric acid. The concentration of GATONE in conc. H₂SO₄ was varied from 4-10% (w/v) whereas in VICTREX^® the concentration was 4% (w/v). The temperature was varied from 35-55°C and the duration of reaction was 3-7 h. Structural characterisation of sulphonated polymers was done by elemental analysis, FT-IR and ¹H-NMR spectroscopy. On the basis of elemental analysis, the extent of sulphonation of GATONE was found to be 57-75%. The extent of sulphonation as determined by ¹H-NMR in case of GATONE was in the range of 53-80% and for VICTREX 58-87%. Thermal analysis, proton conductivity and water uptake of these samples were also studied. Proton conductivity of the films was comparable to the perflourinated polymer (Nafion).     

Iron-Catalysed [3+3] Annulation of Oxime Acetates and Enaminones towards the Synthesis of Multi-Substituted Pyridines

A direct access to unsymmetrical and symmetrical multi-substituted pyridines has been accomplished via iron-catalysed [3+3] annulation of oxime acetates with enaminones. This protocol is featured by easily available starting materials, no requirement of expensive additives and ligands, operational simplicity, and good tolerance with diverse functional groups.