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This Article reports on the ligand integration effect of poly(amidoamine) (PAMAM) dendrimers working in the solid composite systems, which is significant for stabilizing Pd nanoparticles (PdNPs). To carry forward this research, the fourth generation of PAMAM dendrimer (G4) was modified with polymerizable functions and tied to polymer networks constituting porous composites through the polymerization-induced phase separation (PIPS) strategy. The obtained results indicate that creation of PdNPs is strongly affected by the G4 template, and, consequently, unforeseen critical control of their sizes was definitely performed. Also, the crucial importance from perspective of catalytic applications is strong suppression of Pd leaching for the G4-utilized porous polymer composites (G4-p). This fact means that the catalytic event of G4-p entirely occurs on the polymer support. All of these characteristics are in marked contrast to those of the composite that was fabricated with a nonintegrated, small molecule ligand...

The heterocomponent films of polypyridine ruthenium(II) complexes and methyl viologen derivatives, and polypyridine ruthenium(II) complexes and alkyl chain derivatives have been successfully obtained using a layer-by-layer fabrication method. We determined their photocurrent generation properties and noted that the photocurrent generation strongly depended on the inner layer. A higher photocurrent generation in the donor–acceptor film was obtained than in a single-component film of the chromophore.

The new TiO2 photocatalytic filter supported by photo-induced activated hydroxyapatite (HAp Ca10(PO4)6(OH)2) was developed and the complete oxidation of acetaldehyde on the filter was investigated. The photocatalytic filter was fabricated by coating TiO2 and HAp on the porous ceramics body. In the decomposition of acetaldehyde using this composite filter, CO2 generation came to maximum at 20 min after starting of UV (254 nm) irradiation and the value was the stoichiometric to the complete oxidation. The rapid and complete oxidative decomposition of acetaldehyde can be achieved using the new photocatalytic composite filter in spite of the very small contact time, about 0.4 s through the filter and one path method. This effect would not be explained alone by the absorption capacity of HAp for acetaldehyde. Synergic and composite effect of HAp followed by radical formation under light is maximum at 254 nm.

Layer-by-layer (LbL) multilayer films of monomethyl maleate copolymers with styrene (P1) or vinyl carbazole (P2) were fabricated on oxidized surfaces, such as silicon wafers, quartz plates, or indi...

Polymer-dispersed liquid crystal (PDLC) films of 4-cyano-4‘-pentylbiphenyl (5CB) were fabricated between two quartz substrates, the surfaces of which had been modified with the self-assembled monolayers (SAMs) of CH3−(CH2)17−Si(OMe)3 (1), HS−(CH2)10−Si(OEt)3 (2), and NC−(CH2)11−Si(OEt)3 (3). The SAM-modification effects on the molecular aggregation of 5CB were investigated by steady-state and time-resolved fluorescence analysis for the PDLC films. Remarkably, it was found that selective excitation of the interface layer with the substrate surface gave both the monomer and excimer emissions of 5CB in relative intensities, depending on the chemical nature of the SAM surfaces. While the monomer and excimer emissions appeared in comparative intensities in the case of the unmodified quartz surface, the surface modification with the SAM of 1 resulted in a dominant contribution of the excimer emission. By contrast, the monomer emission was much stronger than the excimer emission in the case of the surface modifi...

An efficient synthesis of a structurally unique, novel M(3) antagonist 1 is described. Compound 1 is conveniently disconnected retrosynthetically at the amide bond to reveal the acid portion 2 and the amine fragment 3. The synthesis of key intermediate 2 is highlighted by a ZnCl(2)-MAEP complex 19 catalyzed diastereoselective Michael reaction of dioxolane 7 with 2-cyclopenten-1-one (5) to establish the contiguous quaternary-tertiary chiral centers and a subsequent geminal difluorination of ketone 17 using Deoxofluor in the presence of catalytic BF(3).OEt(2). The synthesis of the amine moiety 3 is highlighted by the discovery of a novel n-Bu(3)MgLi magnesium-halogen exchange reaction for selective functionalization of 2,6-dibromopyridine. This new and practical metalation protocol obviated cryogenic conditions and upon quenching with DMF gave 6-bromo-2-formylpyridine (26) in excellent yield. Further transformations afforded the amine fragment 3 via reductive amination with 35, Pd-catalyzed aromatic amination, and deprotection. Finally, the highly convergent synthesis of 1 was accomplished by coupling of the two fragments. This synthesis has been used to prepare multi-kilogram quantities of the bulk drug.

Polymer-dispersed liquid crystal (PDLC) films of 4-cyano-4‘-pentylbiphenyl (5CB) were fabricated between two surface-modified quartz or indium−tin-oxide (ITO) substrates that had been obtained by deposition of a boronate-terminated self-assembled monolayer, by its controlled hydrolysis, and by subsequent second-layer lamination over the completely hydrolyzed surface. It was shown that both the fluorescence from the interface layers in contact with the substrate surfaces and the electro-optic functions of PDLC devices are systematically changed with the chemical properties of the substrate surfaces (i.e., the polarity and hydroxy densities).

Two distinct synthetic approaches to the biologically active and structurally unique endothelin antagonist J-104132 (1) have been developed Each synthesis involves a highly selective intramolecular cyclization of a late stage intermediate (bottom to top vs top to bottom) produced from a common early intermediate. Both routes initially yielded multi-gram quantities of the desired product, with the former ultimately developed to pilot scale readiness. Several novel reactions have been developed throughout the course of our studies. These involve a mild bromination of a pyridone to form a bromopyridine, a mild and efficient TEMPO catalyzed oxidation of an alcohol to give a carboxylic acid, as well as a novel stereoselective samarium iodide mediated deoxygenation reaction. These reactions have proved to be quite general and have been applied to a wide variety of substrates.

For the purpose of improving the anti-asthmatic activity of 3-(imidazo[1,2-b]pyridazin-6-yl)thiopropanesulfonamide (I), the computer-assisted automated synthesis apparatus developed at Takeda was used to modify the sulfonamide moiety of I. Several kinds of sulfonamide derivatives (1-24) were easily obtained, confirming the usefulness of the automated synthesis apparatus in the laboratory. Anti-asthmatic activity of these derivatives was examined in a platelet activating factor (PAF)-induced bronchoconstriction. Among them, the piperidino-piperidine derivative (13) was found to possess comparable activity to that of I

A new strategy based on polymerization-induced phase separation techniques is utilized to produce palladium nanoparticles captured in a microporous network polymer.

A new strategy based on polymerization-induced phase separation (PIPS) techniques was proposed for fabricating palladium nanoparticles (PdNPs) captured in a microporous network polymer. Pd(OAc)(2) was premixed with a monomer having a poly(amidoamine)-based dendrimer ligand, and subsequently this was thermally polymerized with an excess amount of ethylene glycol dimethacrylate under PIPS conditions. In this system, the formation of PdNPs occurred concurrently with the polymer synthesis in a one-pot process, even with no additional reducing reagent. The resultant microporous polymer was found to have a mesoporosity; the nitrogen sorption analysis gave a specific-surface area of 511 m(2) g(-1), an average pore diameter of 9.9 nm, and a total pore volume of 1.01 mL g(-1). The TEM images of the polymer revealed that the created PdNPs were very small with a diameter of mainly ca. 2.0 nm; the high-resolution images were lattice-resolvable, showing the crystalline nature of the PdNPs (Pd(111) facets). Catalytic performances of the PdNP-containing microporous polymers were investigated for a heterogeneous Suzuki-Miyaura reaction of 4'-bromoacetophenone and phenylboronic acid in water. In the presence of 10(-2) molar equiv of the polymer, the reaction efficiently proceeded at 80 degrees C and gave the desired product, 4-acetylbiphenyl, in >90% yield after 2 h. On the basis of the ICP-AES analysis, the Pd content released into the solution phase was estimated to be only 0.27% of the initial charge. Thereby, this polymer was successfully recovered by simple filtration and reused with only a minimal loss of activity (yield >90% even at the eighth run). When the catalytic reaction was examined with a low amount of the polymer catalyst, the turnover number (TON) reached 8.5 x 10(4) while maintaining a good yield. Finally, the dendrimer template effect of the polymer catalyst was discussed by referring to the catalytic performances of a control polymer prepared with nonintegrated ligand monomers.

Aqueous Bilayers of Glutamate-Based Double-Chain Ammonium Amphiphiles II. Improvement of Polymerization and Membrane Characteristics by Ether-Linked Alkyl Tails

Planar bilayer membranes were obtained from polymerized double-chain ammonium amphiphiles. Their properties were closely related to those of the corresponding aqueous bilayers, and a life time longer than one day was observed for a well-organized polymer sample.

Se-Alkynyl selenocarboxylates (1) were found to readily react with alcohols and amines to give O-alkyl selenocarboxylates (4) and selenoamides (6) in moderate to good yields, respectively. The formation mechanisms of 4 and 6 via selenoketene and ammonium alkyneselenolate, respectively, are proposed.

This paper reports on fabrication of water-compatible palladium nanoparticle (PdNP) catalysts supported on microporous polymers, which show high activity and extremely low Pd leaching behaviour in the usage for carbon cross-coupling reactions. The supported PdNP catalysts were fabricated by utilizing the polymerization-induced phase separation (PIPS) method. An outstanding point of the present study is to use a small molecule ligand monomer (D-m) based on N,N-dimethyl ethylenediamine, instead of the PAMAM dendrimer-based monomer used previously having integrated ligand sites. When D-m that had been complexed with Pd2+ was copolymerized with excess 1,6-hexanediol dimethacrylate (HX) in the PIPS setup, a highly active catalytic polymer (D-HX) having extremely low Pd leaching characteristics was successfully obtained. The TEM images of D-HX revealed that the created PdNPs were small with a diameter of mainly ca. 5.0 nm. Catalytic performances of D-HX were investigated for a heterogeneous Suzuki–Miyaura reaction in water. In the presence of 10−2 molar equiv. of the polymer, the reaction efficiently proceeded at 80 °C and gave the desired product in ca. 90% yield after 2 h. D-HX could be easily recovered by simple filtration and reused with only a minimal loss of activity. Intriguingly, the hot filtration test indicated that nearly no Pd species was thermally released from D-HX, which is in large contrast with the results of other polymers tested herein leading to a lot of Pd leaching. Through this study, it was demonstrated that the microscopic structure of the polymer supports could be well-controlled by changing the structure of monomers and it was closely related to the Pd leaching behaviour of the present heterogeneous catalysis systems.

Inspired by naturally occurring superhydrophobic surfaces, a number of approaches have been attempted to create specific surfaces having both micro- and nanoscale textures. To bring the artificial superhydrophobic surfaces closer to practical applications, a widely usable and simpler method that is systematically derived is required. Here, we describe a unique UV light-triggered micro/nanofabrication system for creating superhydrophobic surfaces, where the basic idea underlying this method comes from polymerization-induced phase separation (PIPS) phenomena. The operation consists of a three-step sequence and can be quickly performed within several minutes under an open-air condition: (1) coating of a precursor mixture for PIPS on a substrate, (2) UV curing to induce phase separation between the growing polymers and solvents, and (3) ethanol flushing to remove solvents to leave a specific texture at the surface. By selecting appropriate components of the PIPS mixture (cross-linkable monomers, solvents, and soluble polymer additives), phase separation rapidly and effectively occurred even in the film UV-polymerization format through the increasing thermodynamic instability; thereby specialized surfaces having micro- and nanoscale textures could be logically constructed. On the basis of the systematic investigation, this method was thus proved to be versatile and applicable for rational design of creating both transparent superhydrophobic films and water repellent fabric textiles.

A versatile automated synthesis apparatus, equipped with a chemical artificial intelligence, was developed to prepare and isolate a wide variety of compounds. The apparatus was to the synthesis of substituted N-(carboxyalkyl)amino-acids. The apparatus [1,2] is composed of units for performing various tasks,for example reagent supply, reaction, purification and separation, each linked to a control system. All synthetic processes, including washing and drying of the apparatus after each synthetic run, were automatically performed from the mixing of the reactants to the isolation of the products as powders or crystals. The reaction of an amino-acid tertbutyl ester acetic acid salt with a 2-keto acid sodium salt produces an unstable intermediate, Schiff base, which is reduced with sodum cyanoborohydride to give a substituted N-(carboxyalkyl)aminoacid tert-butyl ester sodium salt. The equilibrium and the consecutive reactions were controlled by adding sodium cyanoborohydride using the artificial intelligence software, which contained novel kinetic equations [3] and substituent effects [4].Substitued N-(carboxyalkyl)amino-acid tert-butyl esters, 90 derivatives, were automatically synthesized using the computerassisted automated synthesis apparatus. The syntheses were performed unattended 24 hours a day, except for supplying the raw materials, reagents and solvents. The apparatus is extremely valuable for synthesizing many derivatives of a particular compound. The configurations of the products were determined by circular dichroism measurements.

Solid polymer electrolyte membrane has been used as electrolyte in polymer electrolyte fuel cells (PEFC) has high electrical conductivity. The hydrogen peroxide made by the reaction in a fuel cell may degrade the conductivity in PEFC. It is necessary to investigate the degradation behavior of the membrane in the environment where the hydrogen peroxide exists. The membrane that was immersed in hydrogen peroxide was used as a sample of each measurement. The measurement of the proton diffusion rate in the membrane was performed for the measurement of a proton conductivity. The current-voltage curve measurement was performed for the investigation of a fuel cell performance. The measurement of a proton diffusion rate applied to the degradation process in the membrane was effective to evaluate the conductivity in the fuel cell.

Le polymere amphiphile, azoaromatique est prepare par introduction d'un groupe azobenzene dans la chaine laterale de polymethacrylate d'hydroxyethyle

A versatile automated apparatus, equipped with an artificial intelligence has been developed which may be used to prepare and isolate a wide variety of compounds. The prediction of the optimum reaction conditions and the reaction control in real time, are accomplished using novel kinetic equations and substituent effects in an artificial intelligence software which has already reported [1]. This paper deals with the design and construction of the fully automated system, and its application to the synthesis of a substituted N-(carboxyalkyl)amino acid. The apparatus is composed of units for perfoming various tasks, e.g. reagent supply, reaction, purification and separation, each linked to a control system. All synthetic processes including washing and drying of the apparatus after each synthetic run were automatically performed from the mixing of the reactants to the isolation of the products as powders with purities of greater than 98%. The automated apparatus has been able to run for 24 hours per day, and the average rate of synthesis of substituted N-(carboxyalkyl)amino acids has been three compounds daily. The apparatus is extremely valuable for synthesizing many derivatives of one particular compound structure. Even if the chemical yields are low under the optimum conditions, it is still possible to obtain a sufficient amount of the desired product by repetition of the reaction. Moreover it was possible to greatly reduce the manual involvement of the many syntheses which are a necessary part of pharmaceutical research.

A first synthesis of ascidiacyclamide, a cytotoxic cyclic peptide from ascidian, has been achieved through the cyclodimerization with diphenyl phosphorazidate(DPPA), which has unambiguously determined the absolute configuration of ascidiacyclamide as 1 .

Total synthesis of ulithiacyclamide, a strong cytotoxic cyclic peptide from marine tunicates, has been achieved by the use of diphenyl phosphorazidate(DPPA) and diethyl phosphorocyanidate(DEPC). Two different cyclization processes were applied to the construction of this unique cyclic peptide having a disulfide bridge.

To control the swelling of polymer membrane by photoirradiation amphiphilic azoaromatic polymer membranes were prepared and a photoinduced change in the swelling degree of water was investigated. The azobenzene moiety in the side chain of the polymer was isomerized from trans form to cis form by ultraviolet (UV) irradiation and reverse isomerization was found by visible light irradiation. The swelling degree of the polymer membrane for water in the dark was decreased by UV radiation, and when visible light irradiation was carried out in the polymer membrane the degree of swelling recovered to the original level. The swelling degree decreased with an increase in the mole fraction of the azobenzene moiety in the dark and under UV irradiation. The deswelling degree of the polymer membrane by UV irradiation also decreased with an increase in the mole fraction of the azobenzene moiety. This reversible change in the swelling degree was considered to be caused by the photoisomerization of the azobenzene moiety in the polymer membrane.

(S)-Alanyl-(R)-2-bromoabryl-(R)-β-tyrosine found in jaspamide(1) was conveniently synthesized as its protected derivative 2 in good yield.

The first direct X-ray crystal structure determination of a cytotoxic cyclic peptide from ascidian, ascidiacyclamide, has shown a molecular conformation responsible for its biological activity.