Synthesis of theaflavins with Camellia sinensis cell culture and inhibition of increase in blood sugar values in high-fat diet mice subjected to sucrose or glucose loading

Theaflavin and its galloyl esters are major polyphenolic pigments of black tea. We compared the efficiency of a variety of oxidizing enzyme systems to synthesize theaflavin and its galloyl esters. Camellia sinensis cell culture efficiently synthesized theaflavin from epicatechin and epigallocatechin with 70% yield and 100% conversion in 4 min. In an administration experiment performed in mice, theaflavin inhibited the increase blood glucose levels in mice that were fed a high-fat diet and subjected to glucose or sucrose loading in mice.     

Development of a passive micromixer based on repeated fluid twisting and flattening,and its application to DNA purification

We have developed a three-dimensional passive micromixer based on new mixing principles, fluid twisting and flattening. This micromixer is constructed by repeating two microchannel segments, a “main channel” and a “flattened channel”, which are very different in size and are arranged perpendicularly. At the intersection of these segments the fluid inside the micromixer is twisted and then, in the flattened channel, the diffusion length is greatly reduced, achieving high mixing efficiency. Several types of micromixer were fabricated and the effect of microchannel geometry on mixing performance was evaluated. We also integrated this micromixer with a miniaturized DNA purification device, in which the concentration of the buffer solution could be rapidly changed, to perform DNA purification based on solid-phase extraction.     

Preparation of Pd(PPh<Subscript>2</Subscript>H)<Subscript>2</Subscript>(PPh<Subscript>3</Subscript>)<Subscript>2</Subscript> and its Role as a Precursor of a Dinuclear Complex with Bridging Phosphide Ligands

Reaction of PPh₂H with Pd(PPh₃)₄ in a 4:1 molar ratio produced the Pd complex with two diphenylphosphine ligands, Pd(PPh₂H)₂(PPh₃)₂ (1). Complex (1) was characterized by n.m.r. (¹H and ³¹P{¹H}) spectra as well as by elemental analysis. Reaction of (1) with RhCl(PPh₃)₃ yielded a Pd–Rh heterobimetallic complex with bridging phosphide ligands, formulated as [(Ph₃P)₂Pd(μ-PPh₂)₂Rh(PPh₃)₂]Cl (2).     

Nonideal mixing of dodecyltrimethylammonium halides and nonionic surfactant in adsorbed films and micelles

The ion–dipole interaction between dodecyltrimethylammonium cations and nonionic surfactant molecules in adsorbed films and micelles was investigated by concentrating on the difference in the degree of counterion binding by employing dodecyltrimethylammonium chloride (DTAC)–octyl methyl sulfoxide (OMS) and dodecyltrimethylammonium bromide (DTAB)–OMS mixtures. The phase diagrams of adsorption and micelle formation were constructed and then the nonideal mixing of different species of surfactants was demonstrated in terms of the excess Gibbs free energies of adsorption and micelle formation, and the surface excess areas. Furthermore the dependence of them on the counterion was clearly shown. All these results were found to support our previous view that the direct interaction between surfactant cation and the dipole of the hydrophilic part of a nonionic surfactant is essential in cationic-nonionic surfactant mixtures, i.e., the DTAC system with a lower counterion biding has more negative excess thermodynamic quantities than the DTAB system with a higher one.     

Iron‐Complex‐Catalyzed C?C Bond Cleavage of Organonitriles: Catalytic Metathesis Reaction between H?Si and R?CN Bonds to Afford R?H and Si?CN Bonds

The first example of the catalytic C? CN bond cleavage of acetonitrile as well as Si? CN bond formation have been achieved in the photoreaction of MeCN with Et₃SiH promoted by [Cp(CO)₂FeMe]. This catalytic system is applicable to other organonitriles. Several iron complexes [(η⁵‐C₅R₅)(CO)₂FeR′] (R₅=H₅, H₄Me, Me₅, H₄SiMe₃, H₄I, H₄P(O)(OMe)₂; R′=SiMe₃, CH₂Ph, Me, Cl, I) were examined as catalyst, and [Cp(CO)₂FeMe] was found to be the best precursor. A catalytic reaction cycle was proposed, which involves oxidative addition of Et₃SiH to [Cp(CO)FeMe], reductive elimination of CH₄ from [Cp(CO)FeMe(H)(SiEt₃)], coordination of RCN to [Cp(CO)Fe(SiEt₃)], silyl migration from Fe to N in the coordinated RCN, and dissociation of Et₃SiNC from Fe. The reaction with MeCN of [Cp(CO)Fe(py)(SiEt₃)], which was newly prepared and determined by X‐ray analysis, and the reaction of Et₃SiH with MeCN in the presence of a catalytic amount of [Cp(CO)Fe(py)(SiEt₃)] showed that the 16‐electron species [Cp(CO)Fe(SiEt₃)] is the active species in the catalytic cycle (TON up to 251).     

Effect of type of peroxide on cross-linking of poly(l-lactide)

Poly(l-lactide) (PLLA) was cross-linked with various types of peroxides under constant mole ratios of peroxide-derived radicals to PLLA during reactive extrusion. Peroxides were classified into three groups according to their decomposition rates (Group I: fast, Group II: moderate and Group III: slow) and comparisons were performed within each group. Cross-linking behavior was readily understood in terms of free radical efficiency and hydrogen abstraction ability of radicals. In the case of Groups II and III, the weight-average molecular weight (M_w) of cross-linked PLLA increased with overall hydrogen abstraction ability, because slow decomposition caused uniform cross-linking in molten PLLA. In Group I, M_w and gel fraction were higher than other groups despite Group I's lower hydrogen abstraction ability, leading to the conclusion that peroxide decomposition localized in solid PLLA caused partial cross-linking because of rapid decomposition. Furthermore, the efficiency of peroxide-induced cross-linking was investigated using the Charlesby-Pinner equation.     

Two new dimeric coumarins isolated from Murraya exotica

Bismurrangatin and murramarin A, two new coumarins, were isolated from the vegetative branches of Murraya exotica. Murramarin A is a rare type of bicoumarin that connects two coumarin moieties by orthoester structure. The structures were elucidated based on spectroscopic methods, especially by 2D-NMR experiments.     

Electronic structures of aromatic amine N-oxides

The electronic structures of heterocyclic amine N-oxides, nitrones, and nitrile N-oxides were systematically studied by the Pariser-Parr-Pople method. In addition, the intensity of n- ^* transition pertinent to conjugated N-oxide systems has been calculated. The results of these calculations were compared with the experimental ones reported hitherto and also carried out in the present work. The electronic structure and spectra of aromatic amine N-oxides were thus discussed in detail.

---

Zusammenfassung Die elektronische Struktur heterozyklischer Amin-N-Oxide, Nitrone und Nitril-N-Oxide wird systematisch mit Hilfe der Pariser-Parr-Pople-Methode untersucht. Au\erdem wurde die IntensitÄt von n- ^*-übergÄngen konjugierter N-Oxide berechnet. Die Resultate wurden mit bekannten sowie eigenen experimentellen Ergebnissen verglichen. Die Elektronenstruktur und die Spektren aromatischer Amin-N-Oxide wurden so im Detail diskutiert.

---

Résumé La structure électronique d'amine N-oxydes, de nitrones, et de nitrile N-oxydes ont été étudiés systématiquement par la méthode de Pariser-Parr-Pople. De plus, l'intensité de la transition n- ^* des systémes N-oxydes conjugués a été calculée. Les résultats de ces calculs ont été comparés aux résultats expérimentaux rapportés précédemment et également à ceux du présent travail. La structure électronique et le spectre des N-oxydes d'amines aromatiques ont ainsi été discutés en détail.

---

---

Presented at the 21st (Osaka, April 1968) Annual Meeting of the Chemical Society of Japan, and the Symposium of Structure Chemistry and the Electronic State of Molecules (Tokyo, October 1968).