Hydrophilic Pd-phosphines catalyzed one-pot synthesis of substituted isoquinolines,furopyridines and thienopyridines in aqueous medium

A first example of simple and efficient hydrophilic Pd-phosphine complexes catalyzed one-pot three-component reaction of ortho-bromo aldehydes, terminal alkynes and ammonium acetate proceeds through the tandem coupling-imination-annulation path for the synthesis of substituted isoquinolines, furopyridines and thienopyridines in good to excellent yields in green aqueous medium at mild temperature was described.     

Synthesis of Gossypium hirsutum‐derived silver nanoparticles and their antibacterial efficacy against plant pathogens

Malvaceae and Brassicaceae family crops are economically important; however, their production has been markedly decreased in recent years due to various plant pests. Hence, the search for novel classes of efficient biological approaches continues due to unavailability of precise pesticides. The present study was designed to synthesize, characterize and evaluate the efficacy of silver nanoparticles (AgNPs) obtained using stem extract of Gossypium hirsutum (cotton plant) against plant pathogens Xanthomonas axonopodis pv. malvacearum and Xanthomonas campestris pv. campestris. Biosynthesized AgNPs were characterized using UV–visible spectrophotometry, Dynamic Light Scattering, Scanning Electron Microscopy combined with energy‐dispersive X‐ray analysis and Fourier transform infrared spectroscopy. The synthesized AgNPs were spherical in shape with size ranging from 20 to 100 nm. The characterized AgNPs were investigated for their efficacy against bacterial plant pathogens using the paper disc method. In vitro studies with two concentrations of AgNPs (50 and 100 μg mL^?1) showed zone of inhibition 11.0 ± 1.0 and 12.3 ± 0.5 mm for X. axonopodis pv. malvacearum and 9.7 ± 0.6 and 15.33 ± 1.0 mm for X. campestris pv. campestris. Furthermore, the AgNPs exhibited strong antioxidant activity, and a phytotoxicity study on Vigna unguiculata (cowpea plant) showed no toxicity. Overall, the findings suggest that G. hirsutum stem extract could be efficiently used in the synthesis of AgNPs and showed antimicrobial activity against plant pathogens. Hence, the synthesized nanoparticles could be used to combat plant pathogens in the agriculture sector.     

Enhanced Induction of Apoptosis in HaCaT Cells by Luteolin Encapsulated in PEGylated Liposomes—Role of Caspase-3/Caspase-14

Applied Biochemistry and Biotechnology - Luteolin, a naturally derived polyphenol, has shown to induce apoptosis in HaCaT cells. Its role in induction of caspase-14 and thus in the terminal...     

Silver sequestration of halides for the activation of Pd(OAc)2 catalyzed Mizoroki‐Heck reaction of 1,1 and 1,2 ‐ Disubstituted alkenes

A ligand free catalytic system consisting of Pd(OAc)₂ (cat) and stoichiometric quantities of silver salts, AgOAc or AgBF₄, exhibit high efficiency in the Mizoroki‐Heck arylation, transforming aryl iodides and 1,1 as well as 1,2 disubstituted alkenes into 1,1,2 – trisubstituted aryl alkenes in excellent yields in very short reaction times.     

Fruit Extract of Averrhoa bilimbi: A Green Neoteric Micellar Medium for Isoxazole and Biginelli-Like Synthesis

Research on Chemical Intermediates - A transition metal/ligand/additive/promoter-free synthesis of 3-methyl-4-arylmethylene-isoxazol-5(4H)-ones and the Biginelli-like synthesis is carried out in a...     

The Active Site of a Prototypical “Rigid” Drug Target is Marked by Extensive Conformational Dynamics

Drug discovery, in particular optimization of candidates using medicinal chemistry, is generally guided by structural biology. However, for optimizing binding kinetics, relevant for efficacy and off-target effects, information on protein motion is important. Herein, we demonstrate for the prototypical textbook example of an allegedly “rigid protein” that substantial active-site dynamics have generally remained unrecognized, despite thousands of medicinal-chemistry studies on this model over decades. Comparing cryogenic X-ray structures, solid-state NMR on micro-crystalline protein at room temperature, and solution NMR structure and dynamics, supported by MD simulations, we show that under physiologically relevant conditions the pocket is in fact shaped by pronounced open/close conformational-exchange dynamics. The study, which is of general significance for pharmacological research, evinces a generic pitfall in drug discovery routines.     

A novel imidazolium‐supported palladium–chloroglycine complex: copper‐ and solvent‐free high‐turnover catalysts for the Sonogashira coupling reaction

A novel, effective 1‐glycyl‐3‐methyl imidazolium chloride–palladium(II) complex ([Gmim]Cl–Pd(II)) was synthesized and studied as an organocatalyst for the Sonogashira coupling reaction under solvent‐free conditions at 25 °C. The hydrophobic group on amino acid favors reagent diffusion toward the chloroglycine moiety, increasing the catalytic activity of supported palladium complex. By this protocol, different aryl halides (Cl, Br and I) were reacted with phenylacetylene in good to excellent yields with turnover number 8.0 × 10² to 9.6 × 10². The catalyst was recycled for the reaction of bromobenzene with phenylacetylene for eight runs without appreciable loss of its catalytic activity and negligible metal leaching. Copyright © 2012 John Wiley & Sons, Ltd.     

Electrochemical studies of LiMnPO4 as aqueous rechargeable lithium–ion battery electrode

A study of the electrochemical behavior of LiMnPO₄ prepared by RAPET method in different aqueous electrolytes using cyclic voltammetry (CV), galvanostatic charge–discharge experiments, and electrochemical impedance spectroscopy is reported. CV peak current is proportional to the square root of scan rate under 0.2 mV s⁻¹. The system satisfied the required conditions for a reversible system with a resistive behavior. LiMnPO₄ was found to undergo proton insertion at lower concentrations of electrolyte. At higher concentrations or saturated solutions of electrolytes, lithium insertion/de-insertion becomes the main reaction though the effect of proton insertion/de-insertion reaction cannot be ignored. Electrochemical insertion/de-insertion of lithium in LiMnPO₄ was studied using EIS technique. The kinetic parameter, charge transfer resistance (R _ct), obtained by simulating the experimental impedance data with an equivalent circuit showed a minimum at the potential close to the CV peak potential. The cell LiTi₂(PO₄)₃/5 M LiNO₃/LiMnPO₄ delivers a discharge capacity of 84 mAh g⁻¹ in the first cycle at an applied current of 0.2 mA cm⁻² and it retains its initial capacity over 50 cycles with good rate capability.