Synthesis and Properties of the Weakly Coordinating Anion [Me3NB12Cl11]−

The weakly coordinating anion [Me₃NB₁₂Cl₁₁]^? has been prepared by a simple two‐step procedure. The anion [Me₃NB₁₂Cl₁₁]^? is easily obtained in batches of up to 20 g by chlorination of the known [H₃NB₁₂H₁₁]^? anion with SbCl₅ at about 190 °C and subsequent N‐methylation with methyl iodide. Starting from Na[Me₃NB₁₂Cl₁₁], several synthetically useful salts with reactive cations ([NO]⁺, [Ph₃C]⁺, and [(Et₃Si)₂H]⁺) were prepared. Full spectroscopic (NMR, IR, Raman, TGA, MS) characterization and single‐crystal X‐ray diffraction studies confirmed the identity and purity of the products. The thermal, chemical, and electrochemical stability as well as the basicity of the [Me₃NB₁₂Cl₁₁]^? anion is similar to that of the structurally related weakly coordinating 1‐carba‐closo‐dodecaborate and closo‐dodecaborate anions. The facile preparation of the [Me₃NB₁₂Cl₁₁]^? anion and its ideal chemical and physical properties make it a cheap alternative to other classes of weakly coordinating anions.     

Reaction of α,β-poly(N-hydroxyethyl)-DL-aspartamide with derivatives of carboxylic acids

Benzoic acid, acetylsalicylic acid, and 4-acetamidobenzoic acid have been covalently linked by ester bonds to α,β-poly(N-hydroxyethyl)-DL -aspartamide (PHEA), a water soluble and nontoxic polymer, in order to study PHEA as a drug carrier.     

A chemical genetics approach for specific differentiation of stem cells to somatic cells: a new promising therapeutical approach

Cell replacement therapy of severe degenerative diseases such as diabetes, myocardial infarction and Parkinson's disease through transplantation of somatic cells generated from embryonic stem (ES) cells is currently receiving considerable attention for the therapeutic applications. ES cells harvested from the inner cell mass (ICM) of the early embryo, can proliferate indefinitely in vitro while retaining the ability to differentiate into all somatic cells thereby providing an unlimited renewable source of somatic cells. In this context, identifying soluble factors, in particular chemically synthesized small molecules, and signal cascades involved in specific differentiation processes toward a defined tissue specific cell type are crucial for optimizing the generation of somatic cells in vitro for therapeutic approaches. However, experimental models are required allowing rapid and "easy-to-handle" parallel screening of chemical libraries to achieve this goal. Recently, the forward chemical genetic screening strategy has been postulated to screen small molecules in cellular systems for a specific desired phenotypic effect. The current review is focused on the progress of ES cell research in the context of the chemical genetics to identify small molecules promoting specific differentiation of ES cells to desired cell phenotype. Chemical genetics in the context of the cell ES-based cell replacement therapy remains a challenge for the near future for several scientific fields including chemistry, molecular biology, medicinal physics and robotic technologies.     

The Aumann-Gould Integral

We introduce and study a multi-valued integral of Aumann-type where the selectors are Gould integrals of real functions with respect to finitely additive vector-valued measures. We also discuss the relationship between this kind of integral and the M-Gould set-valued integral with respect to a finitely additive multimeasure M. Received: November 17, 2006, Revised: September 17, 2007 and January, 8, 2008, Accepted: March 13, 2008.     

Assembly of a trinuclear metallo-capsule from a tripodal tris(beta-diketone) derivative and copper(II)

A new metallo-capsule has been synthesised that consists of three copper(II) ions and two molecules of a tris-deprotonated tripodal ligand in which three 2,4-pentanedione groups are linked via their gamma-carbons through thioether spacers to the 1,3,5-positions of a triazine core.     

Synthesis of palladium(II) complexes containing a new alpha-D-xylofuranose-modified diphosphine and their application as catalyst precursors in the co- and terpolymerization of CO-ethene and propene

The diphosphine 3,5-dideoxy-1,2-O-isopropylidene-3,5-bis(di(2-methoxyphenyl)phosphanyl)-alpha-D-xylofuranose (o-MeO-xylophos), which differs from the known 3,5-dideoxy-1,2-O-isopropylidene-3,5-bis(diphenylphosphanyl)-alpha-D-xylofuranose (xylophos) by the presence of 2-methoxy substituents on the P-aryl rings, has been synthesized and characterized. These two ligands have been employed to stabilize the Pd(II) complexes [PdCl2(o-MeO-xylophos)] (1a), [PdCl2(xylophos)] (2a), [PdClMe(o-MeO-xylophos)] (1b), [PdClMe(xylophos)] (2b), [Pd(OTs)(H2O)(o-MeO-xylophos)](OTs) (1c) and [Pd(OTs)(H2O)(xylophos)](OTs) (2c). All complexes have been characterized by multinuclear-NMR spectroscopy. The solid-state structure of 1a has been determined by a single crystal X-ray analysis. The Pd-aqua complexes 1c and 2c have been employed to catalyse the CO-ethene and CO-propene copolymerization as well as the CO-ethene-propene terpolymerization reaction in MeOH. The catalytic activity and the molecular weight of the polyketones have been compared to those of the products obtained with analogous catalysts, [Pd(H2O)2(o-MeO-dppp)](OTs)2 (3c) and [Pd(H2O)(OTs)(dppp)](OTs) (4c), bearing the classical 1,3-bis(diphenylphoshino)propane ligand (dppp). Under comparable catalytic conditions, all catalysts produce structurally similar polymeric materials, with 1c yielding the largest propene incorporation as well as the highest productivity of low-molecular-weight terpolymers.     

Stereoselective bioreduction of bulky-bulky ketones by a novel ADH from Ralstonia sp

Ketones with two bulky substituents, named bulky-bulky ketones, as well as less sterically demanding ketones were successfully reduced to the corresponding optically highly enriched alcohols using a novel identified recombinant short-chain alcohol dehydrogenase RasADH from Ralstonia sp. DSM 6428 overexpressed in E. coli.     

Roads less traveled: Nitrogen reduction reaction catalyst design strategies for improved selectivity

Direct electrochemical nitrogen reduction for ammonia production is necessary to reduce the use of fossil fuels from conventional Haber–Bosch methods. Applications of nitrogen reduction electrocatalysts remain inhibited by slow reaction kinetics and low faradaic efficiencies because of competitive H₂ production pathways. Current strategies to address this challenge in selectivity have focused on catalyst design, reactor configuration, and electrolyte conditions. This brief review discusses the thermodynamic and kinetic challenges in the field as well as current underused approaches for selective catalyst development including bimetallic catalysts, transition metal nitrides, and carbon supports.     

7-(2-Anilinopyrimidin-4-yl)-1-benzazepin-2-ones Designed by a “Cut and Glue” Strategy Are Dual Aurora A/VEGF-R Kinase Inhibitors

Although overexpression and hyperactivity of protein kinases are causative for a wide range of human cancers, protein kinase inhibitors currently approved as cancer drugs address only a limited number of these enzymes. To identify new chemotypes addressing alternative protein kinases, the basic structure of a known PLK1/VEGF-R2 inhibitor class was formally dissected and reassembled. The resulting 7-(2-anilinopyrimidin-4-yl)-1-benzazepin-2-ones were synthesized and proved to be dual inhibitors of Aurora A kinase and VEGF receptor kinases. Crystal structures of two representatives of the new chemotype in complex with Aurora A showed the ligand orientation in the ATP binding pocket and provided the basis for rational structural modifications. Congeners with attached sulfamide substituents retained Aurora A inhibitory activity. In vitro screening of two members of the new kinase inhibitor family against the cancer cell line panel of the National Cancer Institute (NCI) showed antiproliferative activity in the single-digit micromolar concentration range in the majority of the cell lines.     

Chemical Composition,Antipathogenic and Cytotoxic Activity of the Essential Oil Extracted from Amorpha fruticosa Fruits

The purpose of this paper was to characterize and investigate the antimicrobial potential of Amorpha fruticosa fruits essential oil (EO). The EO was extracted by hydrodistillation, analyzed by GC-MS, and then evaluated for its interaction with microbial and mammalian cells. The antimicrobial activity was assessed against bacterial and fungal strains, in a planktonic and adherent growth state, using qualitative and quantitative assays. The main components identified in A. fruticosa fruits EO were δ-cadinene, γ-muurolene, and α-muurolene. The Gram-positive strains proved to be more susceptible than Gram-negative bacteria and fungal strains. The EO exhibited good antibiofilm activity, inhibiting the microbial adherence to the inert (96-well plates and Foley catheter section) and cellular substrata. The flow cytometry analysis revealed as one of the possible mechanisms of antimicrobial action the alteration of cell membrane hydrophobicity. The cytotoxicity on the L929 cell line occurred at concentrations higher than 0.3 mg/mL. Taken together, our results demonstrate that A. fruticosa fruits EO contains active compounds with selective inhibitory effect on different microbial strains in planktonic and biofilm growth state, explained at least partially by the interference with microbial membranes due to their hydrophobic character.