MCM-41-SO3H: an efficient,reusable, heterogeneous catalyst for the one-pot,three-component synthesis of pyrano[3,2-b]pyrans

Research on Chemical Intermediates - MCM-41-SO3H, ordered mesoporous silica material MCM-41 with covalently anchored sulfonic acid groups, was used as a solid acid catalyst for the convenient,...     

Contamination of therapeutic human immunoglobulin preparations with apolipoprotein H (β2‐glycoprotein I)

Polyclonal immunoglobulin (Ig) concentrates are important biological medicinal products and the assurance of their quality and safety is crucial. In our present approach we used proteomic methods to check the purity of commercial Ig products of different origin. The experimental setup included nonreducing 2DE or DIGE combined with MALDI‐TOF and the thrombin generation assay, a routine safety test for pharmaceutical Ig preparations, and was complemented by a specific immunoassay. 2DE patterns displayed contaminations with trace amounts of human apolipoprotein H (Apo‐H), transferrin, albumin, and its fragments. In contrast to the latter, Apo‐H is a protein that is active in the coagulation cascade, and thus a potential involvement in thromboembolic events in vivo cannot be excluded. It was found by 2DE and MALDI‐TOF to be a contaminant of several Ig preparations. Spiking experiments of Ig preparations with pure Apo‐H demonstrated an Apo‐H concentration dependent increase in thrombin generation assay values. Traces of Apo‐H are possibly also contributing to unwanted side effects, as already known for factor XIa. The significance of Apo‐H contaminations for these side effects might be verified by detailed analyses of pharmacovigilance data.     

Palladium-catalyzed oxidative C–H bond coupling of indoles and benzaldehydes: a new approach to the synthesis of 3-benzoylindoles

A palladium-catalyzed dehydrogenative acylation of indoles using easily accessible aldehydes as the acyl source is described. This reaction provides a new approach for the synthesis of 3-acylindoles.     

Volatile constituents of flowers and leaves of Anthemis hyalina

The chemical composition of the essential oils of the flowers and leaves of Anthemis hyalina were analyzed by GC and GC-MS for the first time. The oils were found to contain seventy-two components. cis-Chrysanthenyl acetate (14.9% and 17.8%), camphor (11.6% and 1.7%), terpinen-4-ol (8.3% and 1.2%), germacrene-D (5.1% and 2.1%), β-caryophyllene (4.1% and 5.4%), myrcene (3.6% and 16.9%), bicyclogermacrene (3.5% and 0.9%), α-pinene (2.3% and 4.1%), cis-β-ocimene (2.1% and 4.3%) and isospathulenol (0.4% and 4.3%) were found to be the major constituents of the oils of flowers and leaves respectively. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 428–429, September–October, 2006.     

Mixed mode axisymmetric annular cracks in a finite layer: Off angle crack initiation

The solutions of axisymmetric Volterra type climb and glide edge dislocations are obtained in a layer by means of the Hankel transforms. Utilizing the same procedure, Green’s function solution is obtained for a layer under self-equilibration normal ring traction. The distributed dislocation technique is used to construct integral equations for a system of co-axial annular cracks where the layer is under axisymmetric normal loads. These equations are solved numerically to obtain dislocation density on the cracks surfaces. The results are employed to determine stress intensity factors for annular and penny-shaped cracks and the interaction between two co-axial penny-shaped cracks is studied. Moreover, the stress intensity factors of the interacting cracks are determined such that they can be further used in conjunction with strain energy density (SED) failure criterion to obtain the possible direction of crack initiation that may not be apparent under mixed mode conditions.     

Silica-bonded N-propylsulfamic acid as a recyclable catalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones

2,3-Dihydroquinazolin-4(1H)-one derivatives are synthesized via a one-pot,three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded N-propylsulfamic acid(SBNPSA) in refluxing ethanol.     

Comparative electrochemical study of new self-assembled monolayers of 2-{[(Z)-1-(3-furyl)methylidene]amino}-1-benzenethiol and 2-{[(2-sulfanylphenyl)imino]methyl}phenol for determination of dopamine in the presence of high concentration of ascorbic acid and uric acid

The comparative electrochemical behavior of self-assembled monolayers of two Schiff's bases, 2-{[(Z)-1-(3-furyl)methylidene]amino}-1-benzenethiol (FMAB) and 2-{[(2-sulfanylphenyl)imino]methyl}phenol (SIMP) on a bare gold electrode (Au FMAB SAM-modified electrode and Au SIMP SAM-modified electrode, respectively), was investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy in a 0.1 mol L(-1) KCl solution that contains 5.0 × 10(-3) mol L(-1) [Fe(CN)(6)](3-/4-). The results revealed that the modified electrodes showed an electrocatalytic activity toward the anodic oxidation of dopamine by a marked enhancement in the current response and lower overpotential (60 and 90 mV for the Au FMAB and Au SIMP SAM-modified electrodes, respectively) in phosphate buffer solution at pH 6.0. The Au SIMP SAM-modified electrode was applied successfully to the determination of dopamine in the presence of a high concentration of ascorbic acid. Selective detection was realized in total elimination of ascorbic acid response-a method different from the ones based on the potential separations. The detection limit of dopamine was 5.0 × 10(-8) mol L(-1) in a linear range from 1.0 × 10(-6) to 1.2 × 10(-4) mol L(-1) in the presence of 1.0 × 10(-3) mol L(-1) ascorbic acid. The interference studies also showed that the Au SIMP SAM-modified electrode exhibited good selectivity in the presence of a large excess of uric acid and could be employed for the determination of dopamine in pharmaceutical formulations, plasma samples and human urine with adequate selectivity and precision.     

Multi‐responses optimization of simultaneous adsorption of methylene blue and malachite green dyes in binary aqueous system onto Ni:FeO(OH)‐NWs‐AC using experimental design: derivative spectrophotometry method

In this research, response surface methodology (RSM) approach using Central Composite Design (CCD) coupled by derivative spectrophotometry method was applied to develop mathematical model and optimize process parameters for simultaneous adsorption of methylene blue (MB) and malachite green (MG) from aqueous solution using Ni:FeO(OH) ‐ NWs‐AC. The optimal conditions to adsorption of MB and MG in binary mixture solution from aqueous solution were found at pH 8.0, MB concentration 20 mg L^‐1, MG concentration 20 mg L^‐1, adsorbent dosage 0.033 g and contact time 40 min. At these conditions, high adsorption efficiency (99.39% and 100.0% for MB and MG, respectively) was achieved. Among experimental equilibrium, Langmuir isotherm model fitted well with maximum monolayer adsorption capacity of 28.6 and 29.8 mg g^‐1 for MB and MG, respectively. The adsorption kinetic data followed pseudo second‐order kinetics for MB and MG dyes.     

Engineered mesoporous ionic‐modified γ‐Fe2O3@hydroxyapatite decorated with palladium nanoparticles and its catalytic properties in water

A new mesoporous organic–inorganic nanocomposite was formulated and then used as stabilizer and support for the preparation of palladium nanoparticles (Pd NPs). The properties and structure of Pd NPs immobilized on prepared 1,4‐diazabicyclo[2.2.2]octane (DABCO) chemically tagged on mesoporous γ‐Fe₂O₃@hydroxyapatite (ionic modified (IM)‐MHA) were investigated using various techniques. The synergistic effects of the combined properties of MHA, DABCO and Pd NPs, and catalytic activity of γ‐Fe₂O₃@hydroxyapatite‐DABCO‐Pd (IM‐MHA‐Pd) were investigated for the Heck cross‐coupling reaction in aqueous media. The appropriate surface area and pore size of mesoporous IM‐MHA nanocomposite can provide a favourable hard template for immobilization of Pd NPs. The loading level of Pd in the nanocatalyst was 0.51 mmol g^?1. DABCO bonded to the MHA surface acts as a Pd NP stabilizer and can also lead to colloidal stability of the nanocomposite in aqueous solution. The results reveal that IM‐MHA‐Pd is highly efficient for coupling reactions of a wide range of aryl halides with olefins under green conditions. The superparamagnetic nature of the nanocomposite means that the catalyst to be easily separated from solution through magnetic decantation, and the catalytic activity of the recycled IM‐MHA‐Pd showed almost no appreciable loss even after six consecutive runs.     

Variation of Some Physical Properties of Brownmillerite Doped with a Transition Metal Oxide

Hyperfine Interactions - Cement clinker is the main component of Portland cement. It is composed of four main phases. One of them is the brownmillerite or the ferrite phase of cement clinker. It is...