Indium(III) bromide catalyzed direct azidation of α-hydroxyketones using TMSN3

The direct catalytic azidation of 2-hydroxy-1,2,2-triarylethanones occurs at room temperature using 2 mol % of InBr₃ as Lewis acid and TMSN₃ as soluble azide source. 2-Azido-1,2,2-triarylethanones have been isolated in excellent yields. The role of aryl group and stereoelectronic factors indicate that the mechanism may involve the formation of a stable carbenium ion towards azidation.     

Facile One-Pot Synthesis of Novel Tricyclic Dibenzoheterocycles via the Dianion Protocol of Ditopic Ligands

In our ongoing studies on the synthesis of new heterocyclic ring systems via a dianion intermediate, we herein describe the preparation of novel dibenzoazadioxoninone, dibenzoazadioxoninethione, dibenzoazadioxocine, dibenzoazadioxacycloundecine, dibenzoazadioxacyclododecine, dibenzoaza-2-oxodioxaphosphonine, and dibenzoaza-2-oxo-1,3-thioxaphosphonine in good yields.     

N‐Alkylation of Indole Compounds in Modified Wittig–Horner Reaction

N‐Ethyl‐3‐styrylindoles are prepared under modified Wittig–Horner reaction conditions.     

Facile Synthesis of Substituted N-Monoalkylaromatic Amines Under PTC Conditions

Substituted aromatic amides were alkylated under PTC conditions. Compounds with ortho electron withdrawing substituents furnished exclusively monoalkyl amines. A plausible mechanism has been suggested.     

Electrostatic Complementarity Drives Amyloid/Nucleic Acid Co‐Assembly

Proteinaceous plaques associated with neurodegenerative diseases contain many biopolymers including the polyanions glycosaminoglycans and nucleic acids. Polyanion‐induced amyloid fibrillation has been implicated in disease etiology, but structural models for amyloid/nucleic acid co‐assemblies remain limited. Here we constrain nucleic acid/peptide interactions with model peptides that exploit electrostatic complementarity and define a novel amyloid/nucleic acid co‐assembly. The structure provides a model for nucleic acid/amyloid co‐assembly as well as insight into the energetic determinants involved in templating amyloid assembly.     

Chromatography: An important tool for drug discovery

Despite substantial developments of extraction and separation techniques, isolation of natural products from natural sources is still a challenging task. Undoubtedly hybrid methods like liquid chromatography with NMR spectroscopy or liquid chromatography coupled with mass spectrometry made on‐line structure elucidation possible and provided impressive examples of natural product identification without prior isolation, however, in many cases the necessity to get the purified compounds in hand is still a fact. The process begins with the collection of desired plant material which is subjected to the suitable extraction process. The complex crude extracts are then monitored by various chromatographic procedures to separate and quantify the desired compounds. The active plant extracts are then fractionated to isolate the bioactive compounds in their pure form. The fully identified compound is used as a lead for the production of related analogues to modulate the biological activity and to carry out structure‐activity relationship. The major isolated bioactive compound is used for semi‐synthetic modification or total synthesis should be carried out such that it is relatively easy to modify the structure of the lead compound. This is a simple and cost‐effective way to increase the chance to discover lead compounds. The biological activity in vitro and in vivo has to be done after purification.     

Modification in structure of La and Nd co‐doped epitaxial BiFeO3 thin films probed by micro Raman spectroscopy

The influence of La and Nd co‐substitution on structure, electric and magnetic properties of epitaxial thin films of BiFeO₃ (BFO) was examined. We demonstrate structural phase transition in co‐doped La and Nd BFO thin films using Raman spectroscopy. Based on group theoretical analysis of the number and symmetry of Raman lines, we provide strong experimental evidence that the structure has been changed from rhombohedral to monoclinic due to co‐doping in BFO. The change in structure was also reflected in morphology of these films. Room temperature magnetic hysteresis curves showed that doped films exhibit enhanced ferromagnetic properties with remnant magnetization of ~10 emu/cm³ and coercive field of 1.2 kOe. The enhanced magnetic properties highlight the potential applications of doped BLNFO thin film for smart devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Biodegradable Polycaprolactone (PCL) Nanosphere Encapsulating Superoxide Dismutase and Catalase Enzymes

Biodegradable polycaprolactone (PCL) nanosphere encapsulating superoxide dismutase (SOD) and catalase (CAT) were successfully synthesized using double emulsion (w/o/w) solvent evaporation technique. Characterization of the nanosphere using dynamic light scattering, field emission scanning electron microscope, and Fourier transform infrared spectroscopy revealed a spherical-shaped nanosphere in a size range of 812?±?64 nm with moderate protein encapsulation efficiency of 55.42?±?3.7 % and high in vitro protein release. Human skin HaCat cells were used for analyzing antioxidative properties of SOD- and CAT-encapsulated PCL nanospheres. Oxidative stress condition in HaCat cells was optimized with exposure to hydrogen peroxide (H₂O₂; 1 mM) as external stress factor and verified through reactive oxygen species (ROS) analysis using H₂DCFDA dye. PCL nanosphere encapsulating SOD and CAT together indicated better antioxidative defense against H₂O₂-induced oxidative stress in human skin HaCat cells in comparison to PCL encapsulating either SOD or CAT alone as well as against direct supplement of SOD and CAT protein solution. Increase in HaCat cells SOD and CAT activities after treatment hints toward uptake of PCL nanosphere into the human skin HaCat cells. The result signifies the role of PCL-encapsulating SOD and CAT nanosphere in alleviating oxidative stress.     

Microdetermination of Lead in Water Samples,Preconcentration by Coprecipitation Followed by its Atomic Absorption Spectrophotometric Determination

Abstract

The method incorporates coprecipitation of lead on zirconium hydroxide and its quantitative spectrophotometric determination in natural, polluted and synthetic water samples. The method incorporates coprecipitation of lead on zirconium hydroxide and its quantitative determination by AAS using 283.3 nm wavelength.     

4-Aminothiophenol functionalized gold nanoparticles as colorimetric sensors for the detection of cobalt using UV–Visible spectrometry

The 4-aminothiophenol functionalized gold nanoparticles (4-ATP-Au NPs) were used as colorimetric sensors for the detection of Co²⁺ in aqueous solution by using UV–Visible spectrometry. The 4-ATP-Au NPs were characterized by UV–Visible, FT-IR, TEM and dynamic light scattering (DLS) which confirmed their higher binding affinity towards Co²⁺ through coordinate covalent interactions that can be observed with the naked eye. The absorbance ratio (A₅₇₀/A₅₂₃) was linear with Co²⁺ concentration in the range of 15 × 10^?3 to 1 × 10^?3 M with a correlation coefficient of (R ²) 0.994, and the limit of detection was 5.79 × 10^?5 M.