Enantioselective construction of ortho-substituted benzylic quaternary centers using a phenanthroline-Pd catalyst.

A method for Pd-catalyzed asymmetric conjugate addition of ortho-substituted arylboronic acids to cyclic enones was developed. The addition of various ortho-substituted arylboronic acid to ß-substituted cyclic enones, via catalysis with a chiral phenanthroline-Pd complex, formed cyclic ketone products bearing ortho-substituted benzylic all-carbon quaternary centers with good yields and high enantioselectivity.

Determination of Phonon Density of States from Constant-Pressure Heat Capacity Data of Soft Organic Materials in the Glassy and Crystalline States by Using the Real-Coded Genetic Algorithm.

A method was proposed to derive the phonon density [g(ω)] of states of materials from their heat capacity data by using Real-Coded Genetic Algorithm (RCGA) with Just Generation Gap + Real-Coded Ensemble Crossover. The performance of the method was confirmed by testing whether or not the RCGA reproduces a reasonable g(ω) by analyzing the set of heat capacity data evaluated from an initially assumed model g0(ω) composed of Debye and optical modes. As an example, constant-pressure heat capacities (CPs) were measured for soft molecular materials, diphenyl phosphate (DPP) and diphenylphosphinic acid, in the condensed state, and their g(ω)s were determined from the CP data by applying the RCGA. The unusual behavior that the CP value of glass was smaller than the one of the crystal in the temperature range from 10 to 70 K was observed in DPP; the behavior is contrary to that expected ordinarily for the glass as compared with the crystal. The g(ω)s determined by the RCGA demonstrated that the unusual behavior was attributed to the blue shift in g(ω) of ω = 30-240 K in the glass compared with the crystal. The blue shift and other effects were discussed reasonably as originating from the competitive concurrence of strong and weak intermolecular hydrogen bonds in DPP, with the help of determination of their intramolecular vibrations for the isolated molecule by the density functional theory calculation. It was concluded that the method using the RCGA is of value for obtaining the microscopic information of g(ω) from the precise heat capacity data and for investigating any difference between the details of g(ω)s in different phases of materials.

Anomalous 2D-Confined Electronic Transport in Layered Organic Charge-Glass Systems.

To get insight into the nature of the electronic fluid in the frustration-driven charge glasses, we investigate in-plane and out-of-plane charge transport for several quasitriangular-lattice organic systems: θ-(BEDT-TTF)_{2}X [X=RbZn(SCN)_{4}, CsZn(SCN)_{4}, and I_{3}]. These compounds host a charge order, charge glass, and Fermi liquid, depending on the strength of the charge frustration. We find that the resistivity exhibits extreme 2D anisotropy and contrasting temperature dependence between the in-plane and out-of-plane directions in the charge-glass phase, unlike in the charge order and metallic states. The experimental features indicate that the frustration-induced charge glass carries an anomalous 2D-confined electronic fluid with possible charge excitations other than conventional quasiparticles.

Anomalous spin correlations and excitonic instability of interacting 2D Weyl fermions.

The Coulomb interaction in systems of quasi-relativistic massless electrons has an unscreened long-range component at variance with conventional correlated metals. We used nuclear magnetic resonance (NMR) measurements to reveal unusual spin correlations of two-dimensional Weyl fermions in an organic material, causing a divergent increase of the Korringa ratio by a factor of 1000 upon cooling, in marked contrast to conventional metallic behavior. Combined with model calculations, we show that this divergence stems from an interaction-driven velocity renormalization that almost exclusively suppresses zero-momentum spin fluctuations. At low temperatures, the NMR relaxation rate shows an unexpected increase; numerical analyses show that this increase corresponds to internode excitonic fluctuations, a precursor to a transition from massless to massive quasiparticles.

Charge and Lattice Fluctuations in Molecule-Based Spin Liquids.

Spin liquid (SL) systems have been the subject of much attention recently, as they have been theoretically predicted to not freeze, even at 0 K. Despite extensive searches being made for such a system, only a few candidates have been found. All of these candidates share geometrical frustrations that are based on triangular lattices. We applied vibrational spectroscopy to one of the candidates of a molecule-based SL system, and we compared its results against three antiferromagnetic compounds and four charge-ordered compounds. All of their structural motifs belong to triangular lattices. The C=C stretching modes in the SL state indicated that there were charge and lattice fluctuations. These fluctuations were suppressed but non-negligible in the AF compounds. This finding is potentially significant, as it indicates that a hidden lattice and charge fluctuation are the driving force of a geometrical frustration, which eventually leads to a SL state.

Observation of an anisotropic Dirac cone reshaping and ferrimagnetic spin polarization in an organic conductor.

The Coulomb interaction among massless Dirac fermions in graphene is unscreened around the isotropic Dirac points, causing a logarithmic velocity renormalization and a cone reshaping. In less symmetric Dirac materials possessing anisotropic cones with tilted axes, the Coulomb interaction can provide still more exotic phenomena, which have not been experimentally unveiled yet. Here, using site-selective nuclear magnetic resonance, we find a non-uniform cone reshaping accompanied by a bandwidth reduction and an emergent ferrimagnetism in tilted Dirac cones that appear on the verge of charge ordering in an organic compound. Our theoretical analyses based on the renormalization-group approach and the Hubbard model show that these observations are the direct consequences of the long-range and short-range parts of the Coulomb interaction, respectively. The cone reshaping and the bandwidth renormalization, as well as the magnetic behaviour revealed here, can be ubiquitous and vital for many Dirac materials.

Insulating Nature of Strongly Correlated Massless Dirac Fermions in an Organic Crystal.

Through resistivity measurements of an organic crystal hosting massless Dirac fermions with a charge-ordering instability, we reveal the effect of interactions among massless Dirac fermions on the charge transport. A low-temperature resistivity upturn appears robustly irrespective of the pressure and is enhanced while approaching the critical pressure of charge ordering, indicating that the insulating behavior originates from short-range Coulomb interactions. The observation of an apparently vanishing gap in the charge-ordered phase accords with the theoretical prediction of nontopological edge states.

Development of chiral building blocks having a bicyclo[3.3.0]octane framework using a diastereomeric resolution-selective deprotection.

A protocol is presented for an efficient and practical approach to the synthesis of enantiomerically pure bicyclo[3.3.0]octane derivatives from achiral Cs-symmetric bicyclo[3.3.0]octane-2,8-dione using a diastereomeric resolution-selective deprotection method. This method affords chiral building blocks having bicyclo[3.3.0]octane framework with the same site of diastereotopic carbonyl functional group.

Attempt to synthesize 2,3,5,4'-tetrahydroxystilbene derived from 2,3,5,4'-tetrahydroxystilbene-2-O-ß-glucoside (THSG).

An attempt to synthesize aglycone 1 derived from 2,3,5,4'-tetrahydroxystilbene-2-O-ß-glucoside (THSG) via the Wittig reaction and Mizoroki-Heck reaction is described. In the Wittig protocol, 2,3,5,4'-tetramethoxystilbene 2 was obtained. Additionally, a palladium-catalyzed Mizoroki-Heck reaction strategy yielded 2-aryl-2,3-dihydrobenzofuran 13 instead of derivative 12 in good yield.

Anisotropic mobility and carrier dynamics in the ß-type BEDT-TTF salts as studied by inter-layer transverse magnetoresistance.

A new method to estimate an in-plane conduction anisotropy in a quasi-two-dimensional (q2D) layered conductor by measuring the inter-layer transverse magnetoresistance is proposed. We applied this method to layered organic conductors ß-(BEDT-TTF)2X (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, C10H8S8; X = IBr2, I2Br) by applying magnetic field rotating within the basal plane at 4.2 K. We found the anisotropic behaviour of carrier mobility µ. From this, anomalous distribution of carrier lifetime τ on the Fermi surface is derived, by the use of Fermi surface data reported for the materials. Calculations of the non-uniform susceptibility χ0( q ) suggest that carrier scattering is enhanced at specific k -points related to partial nesting of the Fermi surface. The present method is thus demonstrated to be an efficient experimental tool to elucidate anisotropic carrier dynamics in q2D conductors.

New biological activity of Rhinacanthus nasutus extracts.

BACKGROUND: The MeOH extracts from aerial part and roots of Rhinacanthus nasutus were investigated for new biological activities. MATERIALS AND METHODS: The MeOH extract of the root was stepwise separated by organic solvents into n-hexane, EtOAc, n-BuOH and H(2)O layer fractions. Cytotoxic activity against human tumor and normal cells was determined by the MTT method. Nitric oxide (NO) was determined by the Griess method. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity. RESULTS: The MeOH extract of the root showed much higher tumor-specific cytotoxicity than that of the aerial part. The EtOAc fraction of the root showed the highest tumor-specific cytotoxicity, followed by the n-BuOH, n-hexane and H(2)O fractions. None of the four fractions protected the cells from the cytotoxicity of UV irradiation. The n-BuOH fraction not only stimulated NO production by mouse macrophage-like RAW264.7 cells, but also inhibited the lipopolysaccharide (LPS)-stimulated NO production. The EtOAc fraction inhibited the receptor activator for nuclear factor-κB ligand (RANKL)-stimulated osteoclastogenesis of the RAW264.7 cells most potently, followed by the n-hexane, n-BuOH and H(2)O fractions. The n-BuOH fraction slightly, but significantly stimulated osteoclastogenesis. CONCLUSION: Antitumor and macrophage/osteoclast-modulating substances are enriched in EtOAc and n-BuOH fractions of MeOH extract of R. nasutus roots.

Diverse biological activity of Odontioda Marie Noel 'Velano' extracts.

BACKGROUND: Several pharmacologically active substances have been isolated from orchid plants other than Odontioda Marie Noel 'Velano'. Whether or not MeOH extract fractions from O. Marie Noel 'Velano' bulbs exert various biological activities was investigated. MATERIALS AND METHODS: The MeOH extract was stepwise separated by organic solvents into n-hexane, EtOAc, n-BuOH and H(2)O layer fractions. Cytotoxic activity against human tumor and normal cells was determined by the MTT method. Nitric oxide (NO) was determined by the Griess method. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity. RESULT: The EtOAc fraction showed the highest tumor-specific cytotoxicity, followed by the n-hexane and other fractions. The EtOAc and n-BuOH fractions protected the cells from the cytotoxicity induced by UV irradiation. The EtOAc and n-hexane fractions inhibited NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells. The EtOAc fraction most strongly inhibited the receptor activator for nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis, followed by the n-BuOH, n-hexane and H(2)O fractions. CONCLUSION: Most of the biological activities tested were concentrated in the EtOAc fraction, and separation from cytotoxic substances is needed to identify the active principle(s).

Diverse biological activity of Odontoglossum Harvengtense 'Tutu' bulb extracts.

BACKGROUND: Several pharmacologically active substances have been isolated from orchid plants, but not from Odontoglossum Harvengtense 'Tutu'. Whether MeOH extract fractions from Odontoglossum Harvengtense 'Tutu' bulb exert biological activity was investigated. MATERIALS AND METHODS: The MeOH extract was stepwise separated by organic solvents into n-hexane, EtOAc, n-BuOH and H(2)O layer fractions. Cytotoxic activity against human tumor and normal cells was determined by MTT method. Nitric oxide (NO) was determined by Griess method. Osteoclastogenesis was monitored by tartrate-resistant acid phosphatase (TRAP) activity. RESULT: Among four fractions, the EtOAc fraction showed the highest tumor-specific cytotoxicity, and inhibited NO production by lipopoly-saccharide (LPS)-stimulated mouse macrophage-like cells and receptor activator for nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis to the greatest extent. CONCLUSION: As compared with Odontioda Marie Noel 'Velano' bulbs, the anti-tumor and anti-inflammatory substances of Odontoglossum Harvengtense 'Tutu' are concentrated more exclusively into the EtOAc fraction.

Gapless spin liquid of an organic triangular compound evidenced by thermodynamic measurements.

In frustrated magnetic systems, long-range ordering is forbidden and degeneracy of energy states persists, even at extremely low temperatures. Under certain conditions, these systems form an exotic quantum spin-liquid ground state, in which strongly correlated spins fluctuate in the spin lattices. Here we investigate the thermodynamic properties of an anion radical spin liquid of EtMe(3)Sb[Pd(dmit)(2)](2), where dmit represents 1,3-dithiole-2-thione-4,5-dithiolate. This compound is an organic dimer-based Mott insulator with a two-dimensional triangular lattice structure. We present distinct evidence for the formation of a gapless spin liquid by examining the T-linear heat capacity coefficient, γ , in the low-temperature heat capacity. Using comparative analyses with κ-(BEDT-TTF)(2)Cu(2)(CN)(3), a generalized picture of the new spin liquid in dimer-based organic systems is discussed. We also report anomalous enhancement of γ, produced by a kind of criticality inherent to the Pd(dmit)(2) phase diagram.

Pharmacokinetics of nateglinide enantiomers and their metabolites in Goto-Kakizaki rats, a model for type 2 diabetes mellitus.

The pharmacokinetics of (-)-N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine (nateglinide) and its enantiomer (L-enantiomer) was studied in Goto-Kakizaki (GK) rats after intravenous administration of nateglinide or L-enantiomer at a dose of 40 micromol/kg body weight. Nateglinide, its L-enantiomer and their metabolites in serum, bile and urine were determined. The total clearance (CL(tot)) and the volume of distribution (Vd) was slightly higher for nateglinide than those for L-enantiomer in control rats, although the differences were not statistically significant. The cumulative excretions of L-M1 (major metabolite of L-enantiomer) and L-M2 (major metabolite of L-enantiomer) into bile were almost the same as that of M1 (major metabolite of nateglinide)and M2 (major metabolite of nateglinide). In GK rats, CL(tot) and Vd were higher for nateglinide than those for L-enantiomer. The cumulative excretion of L-M1 and L-M2 were not different from those of M1 and M2, respectively, into bile or urine. CL(tot) and Vd for nateglinide or L-enantiomer in GK rats were not different from those in control rats. The total excretion of M1, M2, L-M1, and L-M2 into bile or urine in GK rats was not substantially different from that of control rats. These results suggest that the L-enantiomer of nateglinide shows higher CL(tot) and Vd compared with nateglinide, especially in the diabetic state.

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)2.

Recent studies on the physical properties of the triangular system based on the Pd(dmit)2 salts (dmit=1,3-dithiole-2-thione-4,5-dithiolate) are reviewed. Quantum chemical architectures of the Pd(dmit)2 molecule and its dimer are introduced with emphasis on the strong dimerization of a two-level system, which provides unique physical properties of the salts. The magnetic properties are outlined in view of the magneto-structural correlation specific to the frustrated spin systems. Some newly discovered ground states and their origins are discussed, for which the valence bond formation plays a key role. Among them, the two-level structure is crucial for the novel charge-separated state found in two salts. The valence bond ordering, similar to the spin-Peierls transition, has been found in a two-dimensional frustrated spin system. The physical aspects and possible relation to the pressure-induced superconductivity are discussed.

Electrical properties and electronic states of molecular conductors based on unsymmetrical organometallic-dithiolene gold(III) complexes.

The electronic properties of cation radical salts derived from organometallic mixed-ligand complexes [(ppy)Au(S-S)](ppy- = C-dehydro-2-phenylpyridine(-); S-S(2-) = dithiolene ligand) with Au(III)-C sigma-bond were investigated. A 2:1 salt complex [(ppy)Au(C8H4S8)]2[PF6] (C8H4S8(2-) = 2-((4,5-ethylenedithio)-1,3-dithiole-2-ylidene)-1,3-dithiole-4,5-dithiolate(2-)) exhibited semiconductive behavior under ambient pressure (rho rt = 2.6 Omega cm, Ea = 0.03 eV). Magnetic measurements show that it is a Mott insulator close to the metal-insulator boundary. Raman and infrared spectra have revealed that the complex has a quasi-one-dimensional dimeric structure consisting of uniformly charged donor molecules. The complex exhibits metallic behavior at pressures above 0.8 GPa. In contrast, a similar compound [(ppy)Au(C8H4S6O2)]2[BF4] (C8H4S6O2(2-) = 2-((4,5-ethylenedioxy)-1,3-dithiole-2-ylidene)-1,3-dithiole-4,5-dithiolate(2-)) is a band insulator.

Effects of 8-2 fluorotelomer alcohol on oleic acid formation in the liver of rats.

Effects of 8-2 fluorotelomer alcohol on fatty acid composition of lipid in the liver of rats were investigated. Feeding of male rats with a diet that contained 8-2 fluorotelomer alcohol at concentrations of 0.2, 0.4 and 0.8% (w/w) for 14 d caused a significant increase in proportion and content of oleic acid (18 : 1 (n-9)) in the liver. The treatment of rats with 8-2 fluorotelomer alcohol increased activities of palmitoyl-CoA chain elongase (PCE) and stearoyl-CoA desaturase (SCD) and mRNA expressions for rat fatty acid elongase 2 (rELO2) and stearoyl-CoA desaturase 1 (SCD1), but neither rat fatty acid elongase 1 (rELO1) or stearoyl-CoA desaturase 2 (SCD2), in the liver in dose-dependent manners. Multiple regression analyses, which were performed to estimate relative contribution of PCE and SCD for determination of the proportion or the content of 18 : 1 (n-9), revealed that the three parameters were significantly correlated and that standardized partial regression coefficient of PCE was higher than that of SCD. These results suggest that 8-2 fluorotelomer alcohol caused considerable changes in the composition and the content of fatty acid, especially 18 : 1 (n-9), in the liver by inducing PCE and SCD, and that PCE plays a crucial role in the increased proportion of 18 : 1 (n-9) in the liver of the rats given fluorotelomer alcohol.

Two pressure-induced superconducting anion radical salts exhibiting different spin states at ambient pressure.

Pressure-induced superconducting behavior was found in two anion radical salts, EtMe3Z[Pd(dmit)2]2 (dmit = 1,3-dithiole-2-thione-4,5-dithiolate, Z = P, As), that are Mott insulators and exhibit different magnetic and structural transitions at ambient pressure.