Synthesis and Antimicrobial Studies of Novel Imidazole Containing Bisazetidinones and Bisthiazolidinone Derivatives

A simple, practical, and efficient approach to new series of imidazole containing bisazetidinones ( 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j and 9a , 9b , 9c , 9d , 9e , 9f , 9g , 9h , 9i , 9j ) was prepared by Staudinger [2 + 2] cycloaddition reaction, and bisthiazolidinones ( 8a , 8b , 8c , 8d , 8e , 8f , 8g , 8h , 8i , 8j and 10a , 10b , 10c , 10d , 10e , 10f , 10g , 10h , 10i , 10j ) were obtained by cyclization of bisimines with thioglycolic acid. The bisimines ( 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j and 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j ) were synthesized by the condensation of 3‐(1‐(3‐aminobenzyl)‐4, 5‐dihydro‐1H‐imidazol‐2‐yl) aniline ( 3 , 4 ) with a series of different substituted aromatic aldehydes. All the newly synthesized target compounds were evaluated for their in vitro antimicrobial activity against two Gram‐positive bacteria and two Gram‐negative bacteria. Additionally, these synthesized compounds were tested for their antifungal activities. Few compounds showed very good antibacterial and antifungal activity.     

Structure-based design and analysis of MAO-B inhibitors for Parkinson’s disease: using in silico approaches

Parkinson’s disease (PD) is a degenerative disorder of the CNS, characterized by cerebral depletion of dopamine (DA), hence one of the approaches to delay the depletion of DA is to inhibit its oxidative deamination. Monoamine oxidases (MAO) carry out the oxidative deamination of monoamines like DA. These are intracellular enzymes, located on the outer mitochondrial membrane. MAO-A and MAO-B are the two subtypes of which MAO-B is the most predominant enzyme and is commonly found in the brain. Inhibition of the MAO-B enzyme boosts the effect of both endogenous and exogenous DA. In this study, we have carried out crystal structure analysis and structure-based design of MAO-B inhibitors. We also performed molecular dynamics, flexible docking, induced-fit docking and ADME prediction of the newly designed compounds.     

Regioselective synthesis of 2,3,4- or 2,3,5-trisubstituted pyrroles via [3,3] or [1,3] rearrangements of O-vinyl oximes

The regioselective synthesis of 2,3,4- or 2,3,5-trisubstituted pyrroles has been achieved via [3,3] and [1,3] sigmatropic rearrangements of O-vinyl oximes, respectively. Iridium-catalyzed isomerization of easily prepared O-allyl oximes enables rapid access to O-vinyl oximes. The regioselectivity of pyrrole formation can be controlled by either the identity of the α-substituent or through the addition of an amine base. When enolization is favored, a [3,3] rearrangement followed by a Paal-Knorr cyclization provides a 2,3,4-trisubstituted pyrrole; when enolization is disfavored, a [1,3] rearrangement occurs prior to enolization to produce a 2,3,5-trisubstituted pyrrole after cyclization. Optimization and scope of the O-allyl oxime isomerization and subsequent pyrrole formation are discussed and mechanistic pathways are proposed. Conditions are provided for selecting either the [3,3] rearrangement or the [1,3] rearrangement product with β-ester O-allyl oxime substrates.     

A novel concept for in situ gas-phase laser Raman spectroscopy for solid oxide fuel cell research

A planar solid oxide fuel cell (SOFC) operated with hydrogen at T = 1,123 K was equipped with an optically transparent anode flow field to apply species concentration measurements by 1D laser Raman scattering. The flow channels had a cross section of 3 mm × 4 mm and a length of 40 mm. The beam from a pulsed high-power frequency-doubled Nd:YAG laser (λ = 532 nm) was directed through one channel and the Raman-scattered light from different molecular species was imaged onto an intensified CCD camera. The main goal of the study was an assessment of the potential of this experimental configuration for a quantitative determination of local gas concentrations. The paper describes the configuration of the optically accessible SOFC, the laser system and optical setup for 1D Raman spectroscopy as well as the challenges associated with the measurements. Important aspects like laser pulse shaping, signal background and signal quality are addressed. Examples of measured species concentration profiles are presented.     

Biowaste-Derived,Highly Efficient,Reusable Carbon Nanospheres for Speedy Removal of Organic Dyes from Aqueous Solutions

The current work explores the adsorptive efficiency of carbon nanospheres (CNSs) derived from oil palm leaves (OPL) that are a source of biowaste. CNSs were synthesized at 400, 600, 800 and 1000 °C, and those obtained at 1000 °C demonstrated maximum removal efficiency of ~91% for malachite green (MG). Physicochemical and microscopic characteristics were analysed by FESEM, TEM, FTIR, Raman, TGA and XPS studies. The presence of surface oxygen sites and the porosity of CNSs synergistically influenced the speed of removal of MG, brilliant green (BG) and Congo red (CR) dyes. With a minimal adsorbent dosage (1 mg) and minimum contact time (10 min), and under different pH conditions, adsorption was efficient and cost-effective (nearly 99, 91 and 88% for BG, MG and CR, respectively). The maximum adsorption capacities of OPL-based CNSs for BG were 500 and 104.16 mg/g for MG and 25.77 mg/g for CR. Adsorption isotherms (Freundlich, Langmuir and Temkin) and kinetics models (pseudo-first-order, pseudo-second-order and Elovich) for the adsorption processes of all three dyes on the CNSs were explored in detail. BG and CR adsorption the Freundlich isotherm best, while MG showed a best fit to the Temkin model. Adsorption kinetics of all three dyes followed a pseudo-second-order model. A reusability study was conducted to evaluate the effectiveness of CNSs in removing the MG dye and showed ~92% efficiency even after several cycles. Highly efficient CNSs with surface oxygen groups and speedy removal of organic dyes within 10 min by CNSs are highlighted in this paper.     

Solution of a stefan problem in the theory of laser welding by the method of lines

Use of a laser beam as the source of energy for penetration welding gives rise to a long, thin cylindrical hole surrounded by molten metal. Material moves from the front to the rear of the hole as the workpiece is translated relative to the laser, by flowing around the hole. A computer program has been written which solves the equations governing a 2-dimensional steady-state mathematical model in which the only spatial variations considered are in a plane perpendicular to the axis of the hole. The program uses the method of lines applied to a reformulation of the problem suitable for solution by the isotherm migration technique. Computed results have been found to agree satisfactorily with those derived from an analytical model valid for low speeds of welding, and at higher speeds they give results similar to what is observed in practice, although lack of experimental evidence precludes a detailed quantitative comparison at present.     

A simple molecular theory of double reentrance exhibited by highly polar compounds

We show by simple model calculations that dipole-induced dipole and interchain interactions lead to a parallel alignment of molecules with strong longitudinal dipoles for intermolecular separations below a certain value. On the other hand an antiparallel alignment is favoured for larger separations because of dipole-dipole interactions. We incorporate this change in the intermolecular configuration, which naturally leads to two 'lengths' in the problem, in developing a simple McMillan type molecular theory of the double reentrance phenomenon in which the following phase sequence is observed on cooling the sample: isotropic-nematic-smectic A_d-reentrant nematic-smectic A₁. The calculated properties including the phase diagram are in broad agreement with experimental trends.     

Solvent extraction of Zn/II/ with 1,2,3-benzotriazole into n-hepatanol

A method based on solvent extraction has been developed for the radiochemical separation of Zn/II/ from other elements employing 1,2,3-benzotriazole as a complexing agent and n-heptanol as an extractant. Optimum conditions for the extraction have been established. The effect of various anions and cations on the extraction coefficient value of Zn/II/ has been studied. The stoichiometry of the metal to reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 12.     

Investigation of interaction strategies between pyrazolone dyes and poly(acrylamide-co-acrylic acid)

The removal of dyes from waste water before their discharge into aquatic ecosystems is of substantial concern. Amongst functional macromolecules, the combination of polymers with dyes is a research field of enormous potential with regard to high-performance materials. The present study investigates interactions strategies between P(AM-co-AA) polymer with pyrazolone azo dyes in water as green solvent. These interactions were confirmed by FTIR spectroscopy, Ultra-visible spectroscopy, EDAX analysis, and FE-SEM analysis. Polymer P(AM-co-AA) has porous structure in which dyes present in the water get absorb hence it is use to remove pyrazolone dyes from water.