Triphenylphosphine-Catalyzed,Novel, One-Pot,Multicomponent Synthesis of Functionalized β-Acetamido Carbonyls

An efficient triphenylphosphine-catalyzed synthesis of β-acetamido carbonyls via multicomponent reaction of aromatic aldehydes, enolizable ketones or β-keto esters, acid chlorides and acetonitrile at room temperature is described. The process is remarkably simple, environmentally benign, and uses Lewis base for the first time in such type of reaction.     

An Untargeted Metabolomics Approach for Correlating Pulse Crop Seed Coat Polyphenol Profiles with Antioxidant Capacity and Iron Chelation Ability

Pulse crop seed coats are a sustainable source of antioxidant polyphenols, but are typically treated as low-value products, partly because some polyphenols reduce iron bioavailability in humans. This study correlates antioxidant/iron chelation capabilities of diverse seed coat types from five major pulse crops (common bean, lentil, pea, chickpea and faba bean) with polyphenol composition using mass spectrometry. Untargeted metabolomics was used to identify key differences and a hierarchical analysis revealed that common beans had the most diverse polyphenol profiles among these pulse crops. The highest antioxidant capacities were found in seed coats of black bean and all tannin lentils, followed by maple pea, however, tannin lentils showed much lower iron chelation among these seed coats. Thus, tannin lentils are more desirable sources as natural antioxidants in food applications, whereas black bean and maple pea are more suitable sources for industrial applications. Regardless of pulse crop, proanthocyanidins were primary contributors to antioxidant capacity, and to a lesser extent, anthocyanins and flavan-3-ols, whereas glycosylated flavonols contributed minimally. Higher iron chelation was primarily attributed to proanthocyanidin composition, and also myricetin 3-O-glucoside in black bean. Seed coats having proanthocyanidins that are primarily prodelphinidins show higher iron chelation compared with those containing procyanidins and/or propelargonidins.     

“Beyond an acronym,STEM is…”: Perceptions of STEM

Although STEM is at the forefront of many educational initiatives, little is known about various professionals’ perceptions of STEM. This mixed‐methods study surveyed 164 preservice teachers, inservice teachers, administrators, informal educators, and STEM professionals. Quantitative and qualitative questions on the survey elicited participants’ perceptions of STEM, STEM support, and STEM careers. Quantitative analysis revealed that profession influenced understandings of STEM, importance of STEM, support for STEM, and perceptions of STEM career opportunities. Qualitative analysis provided rich explanations for the differences in perceptions among professions. This study suggests that science teacher educators need to ensure preservice teachers have understandings of STEM and STEM careers, K‐16 educators need to emphasize the current importance of STEM, and administrators and policymakers need to align visions of STEM with curriculum and pacing guides so teachers feel supported in their STEM endeavors.     

Synthesis,Spectroscopic Properties,and Quantum Mechanical Study of 5-Oxo-1-phenyl-4-(piperidin-1-ylmethyl)pyrrolidine-3-carboxylic Acid

Russian Journal of Organic Chemistry - The spectroscopic properties of 5-oxo-1-phenyl-4-(piperidin-1-ylmethyl)pyrrolidine-3-carboxylic acid were investigated using FT-IR, NMR, and UV techniques and...     

A new zwitterionic electrochromatographic stationary phase based on poly(3‐chloro‐2‐hydroxypropyl methacrylate‐co‐ethylene dimethacrylate) reactive monolith

A new reactive monolith, poly(3‐chloro‐2‐hydroxypropyl methacrylate‐co‐ethylene dimethacrylate), poly(HPMA‐Cl‐co‐EDMA) was synthesized and post‐functionalized by taurine (2‐aminoethane sulfonic acid) to obtain a zwitterionic stationary phase for capillary electrochromatography. The new stationary phase contained charged groups such as secondary amine providing anodic electroosmotic flow and sulfonic acid groups providing cathodic electroosmotic flow. Hence, the capillary electrochromatography separations with the new zwitterionic monolith were performed with either anodic or cathodic electroosmotic flow. The electrochromatographic separation of alkylbenzenes and phenols was successfully performed. The zwitterionic monolith also allowed the separation of nucleosides using only electrokinetic mode. Theoretical plate numbers up to ~10⁵ plates/m were achieved. Our study is the first report based on poly(HPMA‐Cl‐co‐EDMA) reactive monolith post‐functionalized with a zwitterionic ligand allowing to operate in both anodic and cathodic electroosmotic flow modes. Copyright © 2014 John Wiley & Sons, Ltd.     

Surface molecularly imprinted magnetic microspheres for the recognition of albumin

A new approach, combining metal coordination with the molecular imprinting technique, was developed to prepare affinity materials. Magnetic poly(glycidyl methacrylate) microspheres in monosize form were used for specific recognition toward the target protein. The magnetic poly(glycidyl methacrylate) microspheres were prepared by dispersion polymerization in the presence of magnetite nanopowder. Surface imprinted magnetic poly(glycidyl methacrylate) microspheres based on metal coordination were prepared and used for the selective recognition of human serum albumin. Iminodiacetic acid was used as the metal coordinating agent and human serum albumin was anchored by Cu²⁺ ions on the surface of magnetic poly(glycidyl methacrylate) microspheres by metal coordination. The magnetic poly(glycidyl methacrylate) microspheres were coated with a polymer formed by condensation of tetraethyl orthosilicate and 3‐aminopropyltrimethoxysilane. The human serum albumin imprinted magnetic poly(glycidyl methacrylate) microspheres were characterized by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy and particle size analysis. The maximum adsorption capacity of human serum albumin imprinted magnetic poly(glycidyl methacrylate) microspheres was 37.7 mg/g polymer at pH 6.0. The selectivity experiments of human serum albumin imprinted magnetic poly(glycidyl methacrylate) microspheres prepared with different concentrations in the presence of lysozyme, bovine serum albumin and cytochrome C were performed in order to determine the relative selectivity coefficients.     

Centri-voltammetric determination of glutathione

Centri-voltammetry is a method for concentrating an analyte on an electrode with the aid of a centrifuge. It can be performed in the presence or the absence of a solid carrier/support. This is followed by a voltammetric (analytical) scan. Specifically, we describe here an application of the technique to the determination of glutathione (GSH). Silica gel is used as the carrier precipitate to which gold nanoparticles were added in order to improve accumulation as a result of their strong affinity for thiols. Voltammetry was performed with a carbon paste electrode modified with multi-wall carbon nanotubes. The response to GSH is linear in the 25 and 800 μM concentration range (the correlation coefficient being 0.9915) and the relative standard deviation is 3.40 % (at 250 μM of GSH and n?=?6). The procedure was successfully applied to the determination of GSH in wine and in synthetic plasma using the standard addition method. The recoveries are 100.8 % and 100.0 %, respectively.

Application of carbon arc‐generated Mo‐ and W‐based catalyst systems to the ROMP of norbornene

This study focuses on the application of the carbon arc‐generated molybdenum‐ and tungsten‐based catalyst systems, MoCl₅? C and WCl₆? C, to effect ring‐opening metathesis polymerization (ROMP) of bicyclo[2.2.1]hept‐2‐ene (norbornene). The results are compared with those previously obtained by the electrochemically generated MoCl₅? ē? Al? CH₂Cl₂ and WCl₆? ē? Al? CH₂Cl₂ systems. The polymer products are characterized using ¹H and ¹³C NMR, gel permeation chromatography, differential scanning calorimetry and thermo gravimetric analysis. According to NMR spectra analyses, the molybdenum‐based catalyst system produced polynorbornene with ca 48% cis structure whereas tungsten system produced ca 56% cis structure polynorbornene and in both cases the polynorbornene had a blocky distribution. Copyright © 2009 John Wiley & Sons, Ltd.     

Antibacterial and antioxidant properties of mixed linkage beta-oligosaccharides from extracted β-glucan hydrolysed by Penicillium occitanis EGL lichenase

The aim of this study was first to ascertain the chemical composition and the physicochemical properties of cereal extracted β-glucan from barley flour. Secondly, to assess the antioxidant properties and the antibacterial properties of extracted β-glucan hydrolysates. The proximate composition, FT-IR and scanning electron microscopy of extracted β-Glucan were studied. Hydrolysates from extracted β-glucan, obtained by lichenase EG_L from Penicillium occitanis, were a mixed linkage beta-oligosaccharides (MLBO) of trisaccharides and tetrasaccharides. MLBO showed a DPPH radical scavenger with IC50 about 1.8 ± 0.01 mg/mL whereas the IC50 of extracted β-glucan was about 5 ± 0.01 mg/mL. MLBO showed a high antioxidative capacity (175 μmol/mL α-tocopherol equivalents) at 5 mg/mL. The antimicrobial activity was confirmed against all tested bacteria especially at 20 mg/mL of MLBO while no inhibition was observed for all the strains used after the addition of either EG_L or extracted β-glucan.