Convergent synthesis of carbonic anhydrase inhibiting bi-heterocyclic benzamides: Structure–activity relationship and mechanistic explorations through enzyme inhibition,kinetics, and computational studies

By using a convergent methodology, a novel series of N-arylated 4-yl-benzamides containing a bi-heterocyclic thiazole–triazole core was synthesized, and the structures of these hybrid molecules, 9a–k , were corroborated through spectral analyses. The in vitro studies of these multifunctional molecules demonstrated their potent carbonic anhydrase inhibition relative to the standard used. The kinetics mechanism was exposed by Lineweaver–Burk plots, which revealed that 9j inhibited carbonic anhydrase non-competitively by forming an enzyme-inhibitor complex. The inhibition constants K_i calculated from Dixon plots for this compound was 1.2 μM. The computational study was also persuasive with the experimental results, and these molecules disclosed good results of all scoring functions and interactions, which suggested a good binding to carbonic anhydrase. So, it was predicted from the inferred results that these molecules might be considered as promising medicinal scaffolds for various diseases related to the uncontrolled production of this enzyme.     

Benzimidazole tethered thioureas as a new entry to elastase inhibition and free radical scavenging: Synthesis,molecular docking,and enzyme inhibitory kinetics

The porcine pancreatic elastase inhibition and free-radical scavenging play a crucial role in age progression. All the series of 10 newly synthesized benzimidazole thioureas ( 4a-j ) were assessed for elastase inhibition and radical scavenging activity to identify the suitable anti-aging ingredient for cosmetics products. The compounds 4e , 4f , 4g , and 4h showed inhibition better than the standard, while compound 4f showed the most significant elastase inhibition with the IC₅₀ value of 1.318 ± 0.025 μM compared with oleanic acid IC₅₀ 13.451 ± 0.014 used ±1.989 and 41.563 ± 0.824, respectively, as standard. Molecular docking studies were performed and the compound 4f showed binding energy of 7.2 kcal/mol. Kinetics studies revealed inhibition of the pancreatic elastase in a competitive manner. The relative binding energy and structure activity relationship (SAR) identified compound 4f as an effective inhibitor of porcine pancreatic elastase. Compounds 4e and 4i showed remarkable free-radical scavenging activity with SC₅₀ values of 26.421.     

Rapid and label-free classification of pathogens based on light scattering,reduced power spectral features and support vector machine

The rapid identification of pathogens is crucial in controlling the food quality and safety. The proposed system for the rapid and label-free identification of pathogens is based on the principle of laser scattering from the bacterial microbes. The clinical prototype consists of three parts: the laser beam, photodetectors, and the data acquisition system. The bacterial testing sample was mixed with 10 mL distilled water and placed inside the machine chamber. When the bacterial microbes pass by the laser beam, the scattering of light occurs due to variation in size, shape, and morphology. Due to this reason, different types of pathogens show their unique light scattering patterns. The photo-detectors were arranged at the surroundings of the sample at different angles to collect the scattered light. The photodetectors convert the scattered light intensity into a voltage waveform. The waveform features were acquired by using the power spectral characteristics, and the dimensionality of extracted features was reduced by applying minimal-redundancy-maximal-relevance criterion (mRMR). A support vector machine (SVM) classifier was developed by training the selected power spectral features for the classification of three different bacterial microbes. The resulting average identification accuracies of E. faecalis,E. coli and S. aureus were 99%, 87%, and 94%, respectively. The overall experimental results yield a higher accuracy of 93.6%, indicating that the proposed device has the potential for label-free identification of pathogens with simplicity, rapidity, and cost-effectiveness.     

Fabrication of Sensitive Potentiometric Cholesterol Biosensor Based on Co3O4 Interconnected Nanowires

Highly sensitive, selective, reliable and inexpensive cholesterol biosensors are highly demanded for the routine monitoring of cholesterol molecules in order to prevent heart failure incidents. In this study, Co₃O₄ nanostructures are synthesized using polyvinyl pyrrolidone surfactant as growth template by a low temperature aqueous chemical growth method. The morphology of nanostructures was investigated by scanning electron microscopy and X‐ray diffraction techniques. The nanostructures exhibit interconnected nanowires like morphology with interconnected network of nanowires. The nanostructures of Co₃O₄ are polycrystalline. The cholesterol oxidase was physically adsorbed on the interconnected nanowires of Co₃O₄ for the chemical sensing of cholesterol molecules. The sensor device detected a wide range of cholesterol from 1×10^?7 M to 1×10^?3 M concentrations with sensitivity of ?94.031 mV/decade. A detection limit of 0.035×10^?7 M cholesterol concentration was observed and a fast response time of 10 s was also noticed. The fabricated device is highly stable, selective, sensitive, reproducible and repeatable. All the collected information about presented cholesterol biosensor indicates its potential application for the monitoring of cholesterol concentrations from human blood serum and real‐life samples.     

Synthesis and structural characterization of binuclear ytterbium(III) complexes with 2-amino and 3-amino benzoic acid

Two novel homobinuclear ytterbium(III) complexes, [Yb₂(2AMB)₆(H₂O)₄] · 2C₂H₆O (I) and Yb₂(3AMB)₆(H₂O)₄] · 3H₂O (II) (2AMB = 2-aminobenzoic acid, 3AMB = 3-aminobenzoic acid) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and X-ray crystallography (CIF files CCDC nos. 950103 (I), 921652 (II)). Complex I crystallizes in triclinic space group \(P\bar 1\) and complex II crystallizes in monoclinic space group P2₁/n. X-ray analysis shows that both complexes (I, II) have the dinuclear structure. The central Yb³⁺ ions in both complexes are eight-coordinated adopting distorted YbO₈ dodecahedral geometry. Each Yb³⁺ ion is coordinated to two O atoms from bridging carboxylate, four O atoms from the chelating carboxylate ligands and two O atoms of water molecules. The crystal structure of I and II are stabilized by N-H…O, O-H…O, O-H…N, and C-H…O hydrogen bonds, C-H…π interactions and weak π-π stacking interactions.     

Stability-Indicating Densitometric High-Performance Thin-Layer Chromatographic Method for the Quantitative Analysis of Biomarker Naringin in the Leaves and Stems of Rumex vesicarius L.

JPC – Journal of Planar Chromatography – Modern TLC - A simple, sensitive, and stability-indicating high-performance thinlayer chromatography (HPTLC)-densitometric method was developed...     

Highly Tin‐Selective Stille Coupling: Synthesis of a Polymer Containing a Stannole in the Main Chain

The incorporation of heavier Group 14 element heteroles into semiconducting polymers leads to unusual optoelectronic properties. However, polymers containing stannoles have not been accessible to date. We report a synthetic route to a well‐defined, stannole‐containing polymer, the first example of this class of π‐conjugated polymers. This route was made possible by developing difunctionalized stannole monomers and highly tin‐selective Stille coupling reactions that leave the tin in the stannole untouched. Compared to poly(3‐n‐hexylthiophene), the resulting polymer displays a remarkable bathochromic shift in its absorption.     

Thermal dry reforming of methane over La2O3 co-supported Ni/MgAl2O4 catalyst for hydrogen-rich syngas production

Research on Chemical Intermediates - The excess emission of greenhouse gases (GHGs) such as CO2 and CH4 is posing an acute threat to the environment, and efficient ways are being sought to utilize...     

Resilient and agile engineering solutions to address societal challenges such as coronavirus pandemic

The world is witnessing tumultuous times as major economic powers including the US, UK, Russia, India, and most of Europe continue to be in a state of lockdown. The worst-hit sectors due to this lockdown are sales, production (manufacturing), transport (aerospace and automotive) and tourism. Lockdowns became necessary as a preventive measure to avoid the spread of the contagious and infectious “Coronavirus Disease 2019” (COVID-19). This newly identified disease is caused by a new strain of the virus being referred to as Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS CoV-2; formerly called 2019-nCoV). We review the current medical and manufacturing response to COVID-19, including advances in instrumentation, sensing, use of lasers, fumigation chambers and development of novel tools such as lab-on-the-chip using combinatorial additive and subtractive manufacturing techniques and use of molecular modelling and molecular docking in drug and vaccine discovery. We also offer perspectives on future considerations on climate change, outsourced versus indigenous manufacturing, automation, and antimicrobial resistance. Overall, this paper attempts to identify key areas where manufacturing can be employed to address societal challenges such as COVID-19.     

Understanding the Origin of Highly Selective CO2 Electroreduction to CO on Ni,N‐doped Carbon Catalysts

Ni,N‐doped carbon catalysts have shown promising catalytic performance for CO₂ electroreduction (CO₂R) to CO; this activity has often been attributed to the presence of nitrogen‐coordinated, single Ni atom active sites. However, experimentally confirming Ni?N bonding and correlating CO₂ reduction (CO₂R) activity to these species has remained a fundamental challenge. We synthesized polyacrylonitrile‐derived Ni,N‐doped carbon electrocatalysts (Ni‐PACN) with a range of pyrolysis temperatures and Ni loadings and correlated their electrochemical activity with extensive physiochemical characterization to rigorously address the origin of activity in these materials. We found that the CO₂R to CO partial current density increased with increased Ni content before plateauing at 2 wt % which suggests a dispersed Ni active site. These dispersed active sites were investigated by hard and soft X‐ray spectroscopy, which revealed that pyrrolic nitrogen ligands selectively bind Ni atoms in a distorted square‐planar geometry that strongly resembles the active sites of molecular metal–porphyrin catalysts.