Synthesis by Stille cross-coupling procedure and electrochemical properties of C3-symmetric oligoarylobenzenes

A series of various C3-symmetric molecules were synthesized by Stille cross-coupling procedure. Monomers have been characterized by ¹H NMR, ¹³C NMR. Received oligomers in the process of electropolymerization, containing thienyl, furyl, and EDOT groups provide good conductivity and show stability in common organic solvents such as CHCl₃, toluene, and CH₂Cl₂ and exhibit thermal stability. Electrochemical results suggest that obtained materials can be successfully used in wide scale of organic-electronic devices such as organic light-emitting diodes (OLEDs), organic field-effect transitors (OFETs), and organic solar cells.     

Unprecedented reaction course of 1-phenyl-2H,6H-imidazo[1,5-c]quinazoline-3,5-dione with 3-M excess of ethylene oxide

Structural Chemistry - The reaction of 1-phenyl-2H,6H-imidazo[1,5-c]quinazolino-3,5-dione (4) with 3-molar excess ethylene oxide was described. The resulting product was characterized by...     

Fungal α-1,3-Glucan as a New Pathogen-Associated Molecular Pattern in the Insect Model Host Galleria mellonella

Recognition of pathogen-associated molecular patterns (PAMPs) by appropriate pattern recognition receptors (PRRs) is a key step in activating the host immune response. The role of a fungal PAMP is attributed to β-1,3-glucan. The role of α-1,3-glucan, another fungal cell wall polysaccharide, in modulating the host immune response is not clear. This work investigates the potential of α-1,3-glucan as a fungal PAMP by analyzing the humoral immune response of the greater wax moth Galleria mellonella to Aspergillus niger α-1,3-glucan. We demonstrated that 57-kDa and 61-kDa hemolymph proteins, identified as β-1,3-glucan recognition proteins, bound to A. niger α-1,3-glucan. Other hemolymph proteins, i.e., apolipophorin I, apolipophorin II, prophenoloxidase, phenoloxidase activating factor, arylphorin, and serine protease, were also identified among α-1,3-glucan-interacting proteins. In response to α-1,3-glucan, a 4.5-fold and 3-fold increase in the gene expression of antifungal peptides galiomicin and gallerimycin was demonstrated, respectively. The significant increase in the level of five defense peptides, including galiomicin, corresponded well with the highest antifungal activity in hemolymph. Our results indicate that A. niger α-1,3-glucan is recognized by the insect immune system, and immune response is triggered by this cell wall component. Thus, the role of a fungal PAMP for α-1,3-glucan can be postulated.     

Separation and Determination of Chemopreventive Phytochemicals of Flavonoids from Brassicaceae Plants

The main aim of this study was to develop a method for the isolation and determination of polyphenols—in particular, flavonoids present in various morphological parts of plants belonging to the cabbage family (Brassicaceae). Therefore, a procedure consisting of maceration, acid hydrolysis and measurement of the total antioxidant capacity of plant extracts (using DPPH assay) was conducted. Qualitative analysis was performed employing thin-layer chromatography (TLC), which was presented to be a suitable methodology for the separation and determination of chemopreventive phytochemicals from plants belonging to the cabbage family. The study involved the analysis of 25 vegetal samples, including radish, broccoli, Brussels sprouts, kale, canola, kohlrabi, cabbage, Chinese cabbage, red cabbage, pak choi and cauliflower. In addition, selected flavonoids content in free form and bonded to glycosides was determined by using an RP-UHPLC-ESI-MS/MS method.     

All‐Conjugated,Rod‐Rod Block Copolymers‐Generation and Self‐Assembly Properties

Based on their rigid‐rod structure all‐conjugated, rod‐rod block copolymers show a preferred tendency to self‐assemble into low‐curvature vesicular or lamellar nanostructures independent from their specific chemical structure and composition. This unique and attractive behaviour is clearly illustrated in a few examples of such all‐conjugated block copolymers. The resulting nanostructured heteromaterials may find applications in electronic devices or artificial membranes.

     

The kinetics of oxirane reaction with alkanethiols in the presence of basic catalysts

Rate constants for the reactions of oxirane with alkanethiols in the presence of basic catalyst were studied at the temperature range of 20–50°C. A mechanism of these reactions has been proposed and appropriate kinetic equation has been presented.     

The formation of a cyclic diacetal of methyl alpha-D-mannopyranoside with a 16-membered macrocyclic loop

The X-ray structure of a diacetal with a 16-membered macrocyclic loop, which was obtained as a product of the condensation of methyl alpha-D-mannopyranoside and 1,4-bis(2-formylphenoxy)butane is presented together with polymeric compounds resulting from polycondensation; a similar polymer was formed in the reaction of methyl 2,3:4,6-di-O-salicylidene-alpha-D-mannopyranoside with 1,4-dibromobutane.     

Some aspects of the stability of ion current in a matrix-assisted laser desorption/ionization source

The effect of laser exposure (the number of laser shots) on the stability of production of matrix (gentisic acid, sinapinic acid, nicotinic acid and benzoic acid) and biomolecule (insulin and cytochrome-c) ions is presented. Two methods of sample preparation, dried-droplet and pressure, were examined. In the case of pressure preparation, the dry powder sample was pressed mechanically with a pressure of 30 MPa. The best results were obtained for the pressure method and gentisic acid as matrix.     

Changes in the order of elution of some organic compounds in high-resolution gas chromatography on polar columns depending on the injection method and water content in the sample

During the GC analysis of apple aroma essence using a capillary column with polar stationary phases, i.e., bonded/crosslinked polyethylene glycol (HP-Innowax) and acid-modified polyethylene glycol (FFAP) the phenomenon of changing the elution order of some compounds was observed ("cross-over phenomenon"). The elution order within two pairs of closely eluting compounds: 2-methylbutyl acetate/pentan-3-ol (internal standard) and trans-2-hexen-1-al/2-methylbutan-1-ol differed between samples introduced onto the column with direct injection and with static headspace method. Experiments carried out on standard solutions of investigated compounds in water-acetone mixtures of gradually reduced water ratio (99:1 to 0:100) proved that changes of elution times leading first to co-elution and subsequently to reversion of elution order of compounds within both pairs depended on the amount of water in the injected sample. The same effect was observed while the amount of water was diminished by reducing the sample volume introduced into the column.