Facile <Emphasis Type="Italic">Aglaia elaeagnoidea</Emphasis> Mediated Synthesis of Silver and Gold Nanoparticles: Antioxidant and Catalysis Properties

A facile and green route for the synthesis of metallic nanoparticles is of significant intriguing, as it provides simple, rapid, clean, nontoxic, easily available, energy-efficient, cost-effective fabrication method. We reported environmentally benign and unexplored plant Aglaia elaeagnoidea flower extract for the synthesis of spherical and crystalline silver (Ag) and gold (Au) nanoparticles with an excellent robustness against agglomeration. The resultant nanoparticles were characterized using UV–Vis spec., FTIR, XRD, FESEM, EDAX, and TEM techniques. The uniqueness of our method lies in fast synthesis (10 min for Ag NPs) and ultra rapid homogeneous and heterogeneous complete degradation of Methylene Blue and Congo Red within few seconds using the synthesized Ag and Au NPs as the catalyst, respectively. Whereas more than 90% conversion of 4-Nitrophenol to 4-Aminophenol within few minutes for homogenous and few seconds for heterogeneous method using Ag and Au NPs were obtained. Hence, the results of this study demonstrate the possible application of biosynthesized of Ag and Au NPs as nanocatalyst in waste water treatment.     

Evaluation of serum metal profile in relation to biri smoking using ICP-MS

The metals intake through tobacco smoking is associated with adverse effects for human health. The present study was aimed to understand the effects of biri smoking on smoker’s serum metal profile. Seven metals, cadmium (Cd), nickel (Ni), lead (Pb), chromium (Cr), copper (Cu), iron (Fe) and zinc (Zn), were analysed in serum samples of 20 biri smokers and 20 non-smokers from North India. The Cd, Ni, Pb, Cr and Cu concentrations were higher while Fe and Zn concentrations were lower in smokers compared to non-smokers. The Fe concentrations, the highest among all metals, seemed to be unassociated with the smoking activity. This study indicated that biri smoking is a contributor to the body burden of Cd, Ni, Cu and Cr in the smoker’s body. The Cd, Ni, Cu and Fe concentrations are non-significantly associated with the age of smokers at p < 0.01 significance level, whereas Pb and Cr concentrations increase and Zn concentrations decrease with the increase in the age of smokers. Serum metal concentrations in the smoker subjects of North India are higher compared to the results of other similar studies. This could be linked to the poor quality of tobacco used in biri. We recommend conducting more detailed and controlled studies in this regard as a smoker is also subjected to other sources of exposure to metals.     

Pesticides as Microemulsion Formulations

Conventional systems like wettable powders, emulsifiable concentrates (ECs), oil in water emulsions (O/W emulsions), water in oil emulsions (W/O emulsions), aqueous suspension concentrates etc. are popularly used as the pesticide formulations. However, the microemulsion systems are preferred for their long-term thermodynamic stability, low viscosity, cost economy, and aesthetic appeal. Such systems provide a method for preparing an isotropic mixture of oil and water. Major advantage of microemulsion is in usage of the widely, easily available, environmentally friendly, and least expensive diluents, water. Formulation of pesticide microemulsion is a difficult task. The present investigation deals with the systematic study to arrive at the economical composition for microemulsion and solubilized systems. These compositions gave maximum stability with the optimum usage of surfactants. The microemulsion and solubilized systems when further diluted with water gave macroemulsion and microemulsion respectively, which were stable over an extended period of time.     

Synthesis of Two Isomeric Tetrasaccharides 0-α-L-Fucopyranosyl-(1→3) and (1→4)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl)-(1→3)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose and a Related Tetrasaccharide 0-α-L-Fucopyranosyl-(1→3)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl-(1→6)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose

ABSTRACT

Synthesis of three tetrasaccharides, namely, 0-α-L-fucopyranosyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-β-D-glucopyranose (7), 0-α-L-fucopyranosyl-(1→4)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (9), and 0-α-L-fucopyransoyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyransoyl)-(1→6)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (15) has been described. Their structures have been established by ¹³C NMR spectroscopy.     

Synthesis of Azetidin-2-Ones from Imines and Acids Using Trichloroacetonitrile-Triphenylphosphine Reagent

A one step synthesis of azetidin-2-ones (3a-j) has been described by the reaction of imines (1) with acids (2) in presence of trichloroacetonitrile, triphenylphosphine and triethylamine.     

Facile and Highly Selective Deprotection of tert‐Butyldimethyl Silyl Ethers using Sulfated SnO2 as a Solid Catalyst

Highly selective deprotection of tert‐butyldimethylsilyl ethers at room temperature has been described using sulfated SnO₂ as an efficient solid catalyst.     

Intramolecular Acylation During Acid Chloride Formation of Some o-Styryl Phenoxyacetic Acids

o-Isopropenyl phenoxyactic acids 1 and 8 on treatment with thionyl chloride followed by aqueous workup furnished the acylated products 4 and 9 in moderate yields. The corresponding acid chlorides could also be cyclised with stannic chloride. The acid chlorides from 10 and 11 however did not undergo cyclisation.     

Efficient Synthesis of (1R)‐[3,5‐Bis(trifluoromethyl)phenyl] Ethanol,a Key Intermediate for Aprepitant,an NK‐1 Receptor Antagonist

Enzyme‐catalyzed efficient synthesis of (1R)‐[3,5‐bis (trifluoromethyl) phenyl] ethanol (R)‐(3), a key intermediate for aprepitant, via enantioselective transesterification of racemic 1‐[3,5‐bis (trifluoromethyl) phenyl] ethanol (RS)‐3 using vinyl acetate as the acyl donor in the presence of Candida antarctica lipase‐B (CAL‐B) in an overall yield of 84% with >99% ee is described.     

Generalized Bernstein‐Kantorovich–type operators on a triangle

In this note, we construct generalized Bernstein‐Kantorovich–type operators on a triangle. The concern of this note is to present a Voronovskaja‐type and Grüss Voronovskaja‐type asymptotic theorems, and some estimates of the rate of approximation with the help of K‐functional, first and second order modulus of continuity. We also obtain Korovkin‐ and Voronovskaja‐type statistical approximation theorems via weighted mean matrix method. Lastly, we show that the numerical results which explain the validity of the theoretical results and the effectiveness of the constructed operators.     

Molecular dynamics simulations of triflic acid and triflate ion/water mixtures: a proton conducting electrolytic component in fuel cells

Triflic acid is a functional group of perflourosulfonated polymer electrolyte membranes where the sulfonate group is responsible for proton conduction. However, even at extremely low hydration, triflic acid exists as a triflate ion. In this work, we have developed a force-field for triflic acid and triflate ion by deriving force-field parameters using ab initio calculations and incorporated these parameters with the Optimized Potentials for Liquid Simulations - All Atom (OPLS-AA) force-field. We have employed classical molecular dynamics (MD) simulations with the developed force field to characterize structural and dynamical properties of triflic acid (270-450 K) and triflate ion/water mixtures (300 K). The radial distribution functions (RDFs) show the hydrophobic nature of CF(3) group and presence of strong hydrogen bonding in triflic acid and temperature has an insignificant effect. Results from our MD simulations show that the diffusion of triflic acid increases with temperature. The RDFs from triflate ion/water mixtures shows that increasing hydration causes water molecules to orient around the SO(3)(-) group of triflate ions, solvate the hydronium ions, and other water molecules. The diffusion of triflate ions, hydronium ion, and water molecules shows an increase with hydration. At λ = 1, the diffusion of triflate ion is 30 times lower than the diffusion of triflic acid due to the formation of stable triflate ion-hydronium ion complex. With increasing hydration, water molecules break the stability of triflate ion-hydronium ion complex leading to enhanced diffusion. The RDFs and diffusion coefficients of triflate ions, hydronium ions and water molecules resemble qualitatively the previous findings using per-fluorosulfonated membranes.