Galloyl-oxypaeoniflorin, suffruticosides A, B, C, and D, five new antioxidative glycosides, and suffruticoside E, A paeonol glycoside, from Chinese moutan cortex.

Five new antioxidative glycosides named galloyl-oxypaeoniflorin, suffruticosides A, B, C, and D, and a new paeonol glycoside named suffruticoside E have been isolated from Chinese Moutan Cortex, the root cortex of Paeonia suffruticosa ANDREWS, together with antioxidative galloyl-paeoniflorin. Their structures were elucidated on the basis of chemical and physicochemical evidences. Galloyl-oxypaeoniflorin, galloyl-paeoniflorin, suffruticosides A, B, C, and D showed more potent radical scavenging and antioxidative effects than alpha-tocopherol.     

Anion receptor functions of lanthanide tris(beta-diketonate) complexes: naked eye detection and ion-selective electrode determination of Cl- anion

Lanthanide tris(fluorinated beta-diketonates) acted as effective receptors of Cl- anion in luminescence sensing and ion-selective electrode systems via highly coordinated complexation.     

Total assignment of the (1)H- and (13)C-NMR spectra for TZT-1027 and related compounds

The total assignment of the (1)H- and (13)C-NMR spectra for TZT-1027 was carried out using various NMR methods (1D, 2D NMR). It was found that TZT-1027 exists in two different conformations resulting from the cis-trans isomerization of the amide bond at N-11 and C-12 in DMSO-d(6). The (1)H- and (13)C-NMR spectra of compound 1 and 2 comprised of the partial structure of TZT-1027 were also assigned to be TZT-1027. These assignments showed that compound 1 is in good agreement with TZT-1027 with regard to formation of the conformers.     

Intramolecular michael addition reaction to chiral vinylic sulfoxides. An enantioselective synthesis of (R)- and (S)-1,7-dioxaspiro[5.5]undecane

(R)- and (S)-1,7-Dioxaspiro[5.5]undecane ((R)-1 and (S)-1), sex pheromone of an olive fly, was each stereoselectively synthesized using an intramolecular Michael addition of hydroxyl group to a chiral vinylic sulfoxide moiety as an asymmetric induction step.     

Separation and concentration of technetium using a Tc-selective extraction chromatographic resin

For⁹⁹Tc separation from environmental samples, liquid-liquid extraction, ion-exchange chromatography and coprecipitation, have been described. Although these methods are removing matrix elements, some combinations of them is necessary for purification and concentration of Tc. Besides, the procedures are time-consuming and generally a week or more is needed to purify Tc in the samples. In this study, a novel extraction chromatographic resin for the separation and preconcentration of Tc from several kinds of solutions is described. The material is shown to retain Tc efficiently and selectively from these solutions. Sorbed Tc is readily recovered using 5 ml of 12M HNO₃ and the recoveries with^95mTc are more than 97% for all sample solutions.     

The bitterness intensity of clarithromycin evaluated by a taste sensor

The purpose of this study was to evaluate the ability of a quantitative prediction method using a taste sensor to determine the bitterness of clarithromycin powder suspensions of various concentrations and of a commercial clarithromycin dry syrup product (Clarith dry syrup, Taisho Pharmaceutical Co., Ltd., Tokyo) containing aminoalkyl methacrylate polymer as a taste-masker. The bitterness of the clarithromycin dry syrup product dissolved in various beverages was also evaluated in gustatory sensation tests and using the taste sensor. In the sensor measurements, three variables were used to predict bitterness in single and multiple regression analysis: relative sensor output (R), the change of membrane potential caused by adsorption (CPA), and CPA/R ratio. The CPA values for channel 3 of the sensor predicted well the bitterness of clarithromycin powder suspensions and their filtered solutions. For Clarith dry syrup, the sensor output was small, suggesting that aminoalkyl methacrylate polymer was successful in almost complete masking of the bitter taste of the dry syrup product. When the bitterness intensities of mixtures of 1 g of Clarith dry syrup with 25 ml of water, coffee, tea, green tea, cocoa, milk, and a sports drink were examined, a good correlation was obtained between the results from human taste tests and the predicted values calculated on the basis of multiple regression analysis using CPA data from channel 4, and the CPA/R ratio from channel 3 of the taste sensor (r(2)=0.963, p<0.005). Co-administration of 1 g of Clarith dry syrup with an acidic sports drink was found to be the most bitter using either method.     

In situ conductivity measurements of LiMn2O4 thin films during lithium insertion/extraction by using interdigitated microarray electrodes

Thin films of LiMn₂O₄ have been prepared by RF magnetron sputtering on interdigitated microarray electrodes. In situ conductivity–potential profiles and cyclic voltammograms during extraction/insertion processes of Li ions were obtained simultaneously in nonaqueous and aqueous electrolyte solutions (1 M LiClO₄/propylene carbonate and 1 M LiCl/water). The electronic conductivity of Li_{1– x} Mn₂O₄ was found not to show metallic transition and maintain its semiconducting state during the extraction/insertion of Li ion. A slight decrease in conductivity was observed with increasing the anodic potential, i.e., with increasing x (lithium extraction) and recovered reversibly when the potential returned to the cathodic side (re-insertion of Li ions). Similar results were obtained in both aqueous and nonaqueous electrolyte solutions. Received: 17 June 1997 / Accepted: 2 January 1998     

Synthesis, structure, and H2O2-dependent catalytic functions of disulfide-bridged dicopper(I) and related thioether-copper(I) and thioether-copper(II) complexes

A disulfide-bridged dicopper(I) complex, [Cu2(Py2SSPy2)](ClO4)2 (1) (Py2SSPy2 = bis(2-[N,N-bis(2-pyridylethyl)-amino]-1,1- dimethylethyl)disulfide), a thioether-copper(I) complex, [Cu(iPrSPy2)](ClO4) (2) (iPrSPy2 = N-(2-isopropylthio-2-methyl)propyl-N,N-bis-2-(2-pyridyl)ethylamine, and a thioether-copper(II) complex, [Cu-(PheSPy2)(H2O)](ClO4)2 (3) (PheSPy2 = N-(2-methyl-2-phenethylthio)propyl-N,N-bis-2-(2- pyridyl)ethylamine), were newly synthesized by the reactions of Cu(ClO4)2.6H2O with a thiol ligand of Py2SH (N,N-bis[2-(2-pyridyl)-ethyl]-1,1-dimethyl-2- mercaptoethylamine) and thioether ligands of iPrSPy2 and PheSPy2, respectively. For complexes 1 and 2, X-ray analyses were performed. Complex 1 crystallizes in the triclinic space group P1, and complex 2 crystallizes in the orthorhombic space group Pbca with the following unit cell parameters: for 1, a = 15.165 (3) A, b = 22.185 (4) A, c = 14.989 (3) A, alpha = 105.76 (1) degrees, beta = 90.82 (2) degrees, gamma = 75.23 (1) degrees, and Z = 2; for 2, a = 17.78 (2) A, b = 17.70 (1) A, c = 15.75 (1) A, and Z = 8. Complex 1 is the first structurally characterized example obtained by the redox reaction Cu(II) + RSH-->Cu(I) + RSSR and has two independent structures (1a, 1b) which mainly differ in S-S bond distances, Cu(I)...Cu(I) separations, and C-S-S-C dihedral angles of the disulfide units. The S-S bond distances of 2.088(7) A in 1a and 2.070(7) A in 1b are indicative of significant activation of the S-S bonds by the dicopper centers. Fragment molecular orbital (FMO) analyses and molecular orbital overlap population (MOOP) analyses based on the extended Hückel method clarify the preferable formation of the disulfide S-S bond in 1 rather than the formation of a thiolate-copper(II) complex within the Py2S- ligand framework. Catalytic functions of complexes 1-3 were investigated with peroxides (H2O2 and tBuOOH) as oxidants. Complex 1 catalyzed the selective oxidation of cyclohexane to cyclohexanol and mediated the cyclohexene epoxidation in the presence of H2O2. A transient dark green intermediate observed in the reaction of 1 with H2O2 is characterized by UV-vis, EPR, and resonance Raman spectroscopies, identifying it as a Cu(II)-OOH species, 1(OOH). The resonance Raman features of the nu(O-O) bands at 822 and 836 cm-1, which are red-shifted to 781 and 791 cm-1, respectively, upon introduction of H2(18)O2, are indicative of formation of two kinds of Cu-OOH species rather than the Fermi doublet and the significant weakening of the O-O bonds. These mechanistic studies demonstrate that by virtue of the electron-donating ability of the disulfide unit the Cu-OOH species can be actually activated for one-electron oxidation, which has been reported so far unfavorable for other vibrationally characterized Cu-OOH species.     

A new and facile route to spiro-ketal skeleton via highly stereoselective CO bond formation by intramolecular Michael addition to δ,β-unsaturated sulfoxides

Diastereoisomerically pure (E)-and (Z)-2-methyl-1,6-dioxaspiro [4.5]-decane (insect pheromone) was efficiently prepared via a highly stereo controlled intramolecular Michael addition of hydroxyl group to an unsaturated sulfoxide moiety during the crucial cyclization step.     

Platelet aggregation inhibitors and inotropic constituents in Pyrolae herba.

The chloroform-soluble and n-butyl alcohol-soluble fractions of water extract of Pyrolae Herba inhibited platelet aggregation induced by arachidonic acid and showed a positive inotropic effect. A new naphthoquinone and a new tetralone derivative and known chimaphilin, acetovanillon, and toluhydroquinone were isolated as active constituents. Three new tetralone derivatives were also obtained from an active fraction. The structures of the new compounds were elucidated.