One-pot synthesis of 1,3,5-tribenzoylbenzenes by three consecutive Michael addition reactions of 1-phenyl-2-propyn-1-ones in pressurized hot water in the absence of added catalysts

Cyclotrimerization of 1‐phenyl‐2‐propyn‐1‐one in pressurized hot water gave 1,3,5‐tribenzoylbenzene in one pot in 65 % yield after 7 min at 200 °C, or in 74 % yield after 60 min at 150 °C. The reaction did not take place in the absence of water, and added base promoted the reaction at 250 °C, suggesting a mechanism of three‐consecutive Michael addition reactions. The reaction rates increased with temperature, but the yield of 1,3,5‐tribenzoylbenzene decreased at the expense of formation of acetophenone as a side product at higher temperatures. p‐Methyl and p‐chloro‐substituents on the phenyl ring retarded and enhanced the reaction, respectively. A mechanism involving the enol of benzoylacetaldehyde at a branching point of the pathway leading to 1,3,5‐tribenzoylbenzene and acetophenone was suggested.     

Synthesis of BMS-309403-related compounds, including [¹⁴C]BMS-309403, a radioligand for adipocyte fatty acid binding protein

Adipocyte fatty acid binding protein (A-FABP; FABP4), which is predominantly expressed in macrophages and adipose tissue, regulates fatty acid storage and lipolysis, and is also an important mediator of inflammation. Here, we report a synthesis of (14)C-labeled 2-[2'-(5-ethyl-3,4-diphenyl-1H-pyrazol-1-yl)biphenyl-3-yloxy]acetic acid (BMS309403), a potent and selective small-molecular FABP4 inhibitor, as a chemical tool for investigating the roles of FABP4 in inflammatory and metabolic disorders. The structure-activity relationship of several BMS derivatives for inhibition of FABP4 is also reported.     

Selective probe of the morphology and local vibrations at carbon nanoasperities

We introduce a way to selectively probe local vibration modes at nanostructured asperities such as tips of carbon nanohorns. Our observations benefit from signal amplification in surface-enhanced Raman scattering (SERS) at sites near a silver surface. We observe nanohorn tip vibration modes in the range 200-500 cm(-1), which are obscured in regular Raman spectra. Ab initio density functional calculations assign modes in this frequency range to local vibrations at the nanohorn cap resembling the radial breathing mode of fullerenes. Careful interpretation of our SERS spectra indicates presence of caps with 5 or 6 pentagons, which are chemically the most active sites. Changes in the peak intensities and frequencies with time indicate that exposure to laser irradiation may cause structural rearrangements at the cap.     

Voltammetric sensing of phosphoproteins using a gallium(III) acetylacetonate-modified carbon paste electrode

The voltammetric detection of phosphoproteins was developed using a gallium(III) acetylacetonate-modified carbon paste electrode. Because phosphate groups of the protein interacted with the gallium(III) ion, the protein was accumulated on the electrode surface. A hexaammine ruthenium(III) ion, which combined with the functional groups, was used to monitor the interaction. When phosvitin and hexaammine ruthenium(III) ions were incubated in 0.1 M acetate buffer (pH 3.2), a reduction peak of hexaammine ruthenium(III) ion at the electrode decreased as the concentration of the protein increased. In contrast, an increase in the peak current was observed with a plain carbon paste electrode. These results were caused by a competitive reaction of the phosphate groups with the hexaammine ruthenium(III) and gallium(III) ions. In the presence of α-, β- and κ-caseins, the electrode response decreased due to the order of the numbers of phosphate groups. This method could be applied to the sensing of phosphoproteins at the 10(-10) M level.     

In operando X-ray absorption fine structure studies of polyoxometalate molecular cluster batteries: polyoxometalates as electron sponges

We carried out in operando Mo K-edge X-ray absorption fine structure measurements on the rechargeable molecular cluster batteries (MCBs) of polyoxometalates (POMs), in which a Keggin-type POM, [PMo(12)O(40)](3-), is utilized as a cathode active material with a lithium metal anode. The POM-MCBs exhibit a large capacity of ca. 270 (A h)/kg in a voltage range between V = 4.0 V and V = 1.5 V. X-ray absorption near-edge structure analyses demonstrate that all 12 Mo(6+) ions in [PMo(12)O(40)](3-) are reduced to Mo(4+) in the discharging process. This means the formation of a super-reduced state of the POM, namely, [PMo(12)O(40)](27-), which stores 24 electrons, and this electron number can explain the large capacity of the POM-MCBs. Furthermore, extended X-ray absorption fine structure analyses reveal the molecular structure of [PMo(12)O(40)](27-), which is slightly reduced in size compared to the original [PMo(12)O(40)](3-) and involves Mo(4+) metal-metal-bonded triangles. Density functional theory calculations suggest that these triangles are formed because of the large number of additional electrons in the super-reduced state.     

Evaluation of the thermal effect on separation selectivity in anion-exchange processes using superheated water ion-exchange chromatography

The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 °C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature.     

Electrochemical assay of concanavalin A-ovalbumin binding on magnetic beads

To monitor protein-glycoprotein interactions on magnetic beads, the present study developed an electrochemical assay of the binding between concanavalin A (ConA) and ovalbumin (OVA). The system was a powerful model that could be used to evaluate cell junctions. ConA with an electroactive daunomycin was immobilized on 6 different sizes of magnetic beads (diameter: 1.0-8.9 μm) through a cross-linking agent. Six sizes of OVA-beads (diameter: 1.0-8.9 μm) were also prepared using a similar method. The binding was evaluated using an oxidation peak of ConA with daunomycin because ConA recognized OVA with α-mannose residues. When binding took place on the beads' surface, the peak current was decreased due to the electroactive moieties being covered with OVA. When ConA/daunomycin-OVA binding was evaluated, the change of the peak current obtained by the beads (diameter: 8.9 μm) modified with ConA and daunomycin was the greatest in the presence of OVA-modified beads (diameter: 2.5 μm). In contrast, particle agglomeration was observed for the smallest beads (diameter: 1.0 μm) with ConA/daunomycin and OVA. The results suggested that ConA-OVA binding depended on the size of beads. Thus, this method could be applied to measure protein-glycoprotein interactions on the cell surface.     

Synthesis and electrophoretic deposition of high-dielectric-constant SrTiO3 nanoparticles

We have investigated on the synthesis of SrTiO₃ nanoparticles whose bulk exhibits dielectric constant of 300, and their colloidal dispersion. As a result, we successfully synthesized SrTiO₃ nanoparticles with an average diameter of 134–485 nm measured by a scanning electron microscopic observation. The SrTiO₃ nanoparticles with a negative charge (ζ = −25 to −31 mV) can be dispersed as colloidal nanoparticles in water, and the average diameter in the dispersion were 138–356 nm measured by a dynamic light scattering technique. The colloidal dispersion of SrTiO₃ nanoparticles is promising for fabrication of low-voltage organic field-effect transistors (FETs) by a wet-processing fabrication. We have also successfully prepared SrTiO₃ films with a thickness of 1–10 μm on n-doped silicon substrates by an electrophoretic deposition technique. The SrTiO₃ films on the silicon substrates are likely used as dielectric gate insulator to low-voltage organic FETs after a sintering treatment.     

Inhibitors of adhesion molecules expression; the synthesis and pharmacological properties of 10H-pyrazino[2,3-b][1,4]benzothiazine derivatives

During a search for novel, orally-active inhibitors of upregulation of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1), we found a new series of 10H-pyrazino[2,3-b][1,4]benzothiazine derivatives to be potent ICAM-1 inhibitors. Of these compounds, N-[1-(10H-Pyrazino[2,3-b][1,4]benzothiazin-8-ylmethyl)piperidin-4-yl]-N',N'-dimethylsulfamide 7p showed the potent oral inhibitory activities against neutrophil migration in a murine interleukin-1 (IL-1) induced paw inflammation model. The synthesis and structure-activity relationships of these amide derivatives are described.     

Novel self-assembling organogelators by combination of a double chain-alkylated L-glutamide and a polymeric head group

This communication introduces a new class of self-assembling organogelators composed of a double chain-alkylated L-glutamide with a polymeric head group.