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The introduced catalyst can be recycled by simple filtration and reused for the hydrodeoxygenation at least twice without severe loss of its catalytic performance.

The heterogeneous silicotungstate catalyst can be recovered by filtration and reused for the dehydration at least three times without significant loss of catalytic activity.

In the presence of Rh(2)(OAc)(4) (OAc = acetate) and TBA(2)WO(4) (TBA = tetra-n-butylammonium), the N-silylation of indole derivatives with hydrosilanes efficiently proceeded to give the corresponding N-silylated indoles in high yields. Pyrrole and carbazole were also N-silylated with the combined catalysts.

Composite of Pt and H4SiW12O40 could store H2 as protons and electrons, and H2 stored in the composite could quantitatively be released as H2 without formation of H2O. The H2 storage-release cycles could be repeated at least six times without an appreciable loss of its performance.

Article de synthese: caracteristiques des sondes luminescentes et phosphorescentes, melanges de polymeres et separation de phase, coefficient de diffusion d'une molecule de polymere dans l'etat solide, les temperatures de transition Tg, Tβ et Tγ, volume libre. Application de la technique au durcissement de reseaux epoxy et a la polymerisation de composes vinyliques

A series of (porphyrin)–(C≡C)2–C6H4–R1 (R1 = NO2, H, Me, and OMe) were synthesized by the oxidative coupling of ethynyl porphyrins and phenylacetylenes in the presence of copper(II) acetate in pyridine. Electronic and electrochemical spectra of the compounds with R1 = H, Me, and OMe are quite similar, while pronounced change was observed for the compound with R1 = NO2, especially for the meso-substituted one, indicating that intramolecular charge transfer is responsible for the difference.

Catalytic cyclohexane dehydrogenation, yielding cyclohexene and dihydrogen, proceeded under photoirradiation on either a three-coordinated complex, RhCl(PCy3)2 (Cy = cyclohexyl), or a dihydride complex, RhClH2(PCy3)2, with almost the same turnover frequencies (8.4 or 8.6, respectively) attained by use of a cut-filter (UV-27) under refluxing conditions (354 K). RhCl(PCy3)2 in cyclohexane gave stoichiometric amounts of cyclohexene and RhClH2(PCy3)2 at 354 K; the latter complex yielded little H2 even at 373 K in toluene. A photocatalysis cycle for cyclohexane dehydrogenation with RhCl(PCy3)2 is proposed, where cyclohexene is yielded by thermal C–H bond dissociation and dihydrogen is photoeliminated from RhClH2(PCy3)2, regenerating the original complex.

A facile synthesis of 6-hydroxyindole-3-acetic acid 1a, which is the proposed aromatic subunit of NPTX-1∼6, is described. Radical cyclization of isonitrile 2 successfully afforded 9 in high yield. The aromatic subunit of NPTX-1∼6 was confirmed as 4-hydroxyindole-3-acetic acid 12 by comparison of the 1H-NMR spectra with those of authentic 4- and 6-hydroxyindole-3-acetic acids.

Spiders belonging to the genera, Nephila, Nephilengys, Araneus, etc., possess various polyamine toxins in their venom glands which paralyze insects by blocking the nerve-muscle signal transduction of glutaminergic synapses. More than 50 kinds of polyamine toxin analogs have been characterized which consist, in general, of the aromatic or heteroaromatic moiety connected with the combination of various types of polyamine chains. We are developing a new analytical system by means of a modern mass spectrometric technique which satisfies more rapid, highly sensitive and simple clean-up procedure without complicated chromatographic treatment. The trial of such approach has been performed by employing crude spider venom as the model material. This review article concerns with such proceeding of mass spectrometric analysis by microcolumn HPLC hyphenated FAB-MS system, continuous flow FAB-MS/MS system with high energy collision charge-remote fragmentation, solid and liquid matrix assisted laser desorption ionization (MALDI- and liquid MALDI-) technique connected with tandem mass spectrometer performing in the institute and in addition, femto-molar characterization of new spider venom spider polyamine toxins as a result of the application of such new techniques is addressed. Language: ja

The first total synthesis of Nephilatoxin-1 (NPTX-1), a Joro spider ( Nephila clavata ) toxin having a 4-hydroxyindole nucleus, has been achieved by using two key azide intermediates.

A new type of fluoride ion catalyzed allylation agent, o -bis(allyldimethylsilyl)benzene ( 1a ) and bis(allyldimethylsilyl)methane ( 1b ), can be successfully utilized for various carbonyl substrates. The rate acceleration is ascribable to the shift of equilibrium to complex with Bu 4 NF by the favorable chelation of bis(silane) toward the fluoride ion.

The first total synthesis of NPTX-5 and NPTX-6, Joro spider ( Nephila clavata ) toxins having a 4-hydroxyindole nucleus and a unique putreanine trimer and tetramer acylpolyamine chain, respectively, has been achieved by the iterative use of a key azide compound.

Simultaneous reduction/oxidation sequence of hydroxy carbonyl substrates through Meerwein-Ponndorf-Verley reduction can be facilitated in the presence of bidentate aluminum catalyst, (2,7-dimethyl-1,8-biphenylenedioxy)bis(dimethylaluminum). This new approach provides the opportunity for efficient hydride transfer between two remotely situated functional groups.

The reactions of alkenylselenonium salts with chiral secondary alkoxides afforded chiral (Z)-O-alkyl enol ethers in good yields and, especially in the case of sterically hindered secondary cyclic alcohols, the best results were obtained from reactions of dimethylalkenylselenonium salt 7b with alkoxides prepared from PhLi and the corresponding alcohols in THF at –78 °C.

Transmission electron microscope (TEM) observation at room temperature of the low temperature phase of Ni2.14Mn0.86Ga shows stress-induced 5 periodicity modulation along a pseudo-[111] cubic zone axis. On cooling to 173 K, the periodicity changes to 7. In stress-free areas, a [001] zone axis with new lattice parameters for the tetragonal phase was observed. The new lattice parameters are smaller by a factor of √2 than the expected lattice parameters. A new model for the tetragonal compound Ni2MnGa and the non-stoichiometric phases was developed with the help of TEM data, X-ray powder diffraction measurements, and a computational simulation based on the X-ray powder diffraction patterns.

The first example of the benzyne generation was found in the reactions of alkynylselenonium salt 1a with 1.0 equiv. of phenyllithium in THF at room temperature for 3 h. The formation of the aryne intermediate was confirmed in the reactions of alkynylselenonium salt 1b and tri-p-tolylselenonium salt 6b with tolyllithium, which gave a mixture of alkynylbiphenyl derivatives 18 and 19 in 19% yield (18:19=11:8) and a mixture of bitolyls 28 and 29 in 63% yield (28:29=2:1), respectively. The reaction mechanisms of these reactions are discussed.

New type of fluoride ion catalyzed allylation agent (1a, 1b), allenylation agent (9, 10), and alkynylation agent (17) can be successfully utilized for various carbonyl substrates. The rate acceleration is ascribable to the shift of equilibrium to the chelate complexes with Bu4NF by the favorable chelation of bis(silyl) compounds toward the fluoride ion. The 19F NMR spectrum (ethyl trifluoroacetate as external standard) of a mixture of 1a and Bu4NF in CDCl3 showed two peaks at δ −81.75 and −77.67 (integration ratio∼9:1). The large signal corresponds to the original peak of Bu4NF and the small one might be ascribed to the chelate complex [B] between 1a and Bu4NF. The fluoride ion mediated reaction of bis(crotyldimethylsilyl)methane (7) with benzaldehyde was examined and the only γ-adduct 8 was obtained regioselectively.

The treatment of alkynylselenonium salt with benzenesulfinic acid in iPrOH gives (Z)-β-sulfonylvinylselenonium salts in good yields. The alkenylselenonium salts thus prepared react with nucleophiles such as alkoxides, halides, and acetylides to produce β-functionalized (Z)-vinyl sulfones in high yields. Furthermore, we succeeded in the simple stereoselective one-step synthesis of various chiral (Z)-β-alkoxyvinyl sulfones by the use of chiral alcohols.

A novel spider toxin, NPTX-594, comprised of four constituents: i.e., 2,4-dihydroxyphenylacetic acid (Dhpa), asparagine, 4,8-diaza-1,12-dodecanediamine (Dada), and lysine, was chemically synthesized. The synthetic compound was completely identical with the natural product as regards 1H NMR and mass spectra. The structure of NPTX-594 was thus determined synthetically to be N12-(Dhpa-Asn)-N1-Lys-Dada, as proposed by spectrometric elucidation.

A highly efficient catalytic procedure for Meerwein-Ponndorf-Verley (MPV) reduction has been devised by employing (2,7-dimethyl-1,8-biphenylenedioxy)bis(dialkoxyaluminum) (3) as a catalyst. For example, reduction of 4-phenylcyclohexanone in CH 2 Cl 2 with i-PrOH (1 equiv) as a hydride source in the presence of a catalytic amount of the in situ generated 3a ( 1 mol%) smoothly proceeded at room temperature within I hour to furnish 4-phenylcyclohexanol in 82% isolated yield. In sharp contrast, the conventional MPV reduction with stoichiometric Al(i-PrO) 3 resulted in the recovery of the starting ketone under similar conditions. Our approach also enabled the reverse reaction of MPV reduction, i.e., Oppenauer (OPP) oxidation in a truly catalytic manner. Furthermore, these findings prompted us to develop a simultaneous intramolecular reduction/oxidation of hydroxy carbonyl substrates via the MPV reaction process in the presence of bidentate aluminum catalyst 1, where highly chemoselective hydride transfer from a secondary alcohol moiety to the remote carbonyl group took place. Finally, we demonstrate that the modern MPV system is applicable to highspeed, catalytic Tishchenko reactions. For instance, the dimerization product of cyclohexanecarbaldehyde was obtained in almost quantitative yield using only 0.2 mol% of catalyst 3a. Based on this result, highly stereoselective intramolecular Tishchenko reduction of a β-hydroxy ketone was also accomplished successfully.

Treatment of N-arylmethyl-N-methyl-cis-3-phenylsulfanyl acrylamide (5) with p-toluenesulfonic acid induced two reactions; cyclization to 1,2-dihydrobenz[c]azepin-3-ones (7) and N-dearylmethylation to N-methylacrylamides (9 and 10) depending on the structures of the substrates. The route provides a simple method of preparing 6-methoxy- (7e), 8-methoxy- (7d), 6,8-dimethoxy- (7f), and 8,9-dimethoxy-N-methyl-1,2-dihydrobenz-[c]azepin-3-ones (7g), although the scope is limited by some side reactions.

The inter- and intramolecular addition of nitrogen pronucleophiles to methylenecyclopropanes proceeds smoothly in the presence of palladium catalyst, giving the corresponding hydroamination products in good to excellent yields. The reaction proceeds mainly through cleavage of a distal bond of methylenecyclopropanes.

Oral drug delivery is generally the most desirable means of administration, mainly because of patient acceptance, convenience in administration. Intestinal absorption mechanisms of anionic drugs have been mainly explained by the passive diffusion of nonionized compounds. However, several studies have suggested the involvement of specific transporters in intestinal absorption of weak acids including monocarboxylates. (-)-N-(trans-4-Isopropylcyclohexanecarbonyl)-D-phenylalanine (nateglinide) is a oral hypoglycemic agent possessing a carboxyl group and a peptide-type bond in its structure. Although nateglinide quickly reaches the maximal serum concentration after oral administration, nateglinide itself is not transported by PepT1 or MCT1. We demonstrated that nateglinide transport occurs via a single system that is H(+) dependent but is distinct from PepT1 or MCT1. In clinical, patients usually take many kinds of drugs at the same time. Thus, drug-drug interactions involving transporters can often directly affect the therapeutic safety and efficacy of many drugs. However, there have been few studies on food-drug interactions involving transporters. Dietary polyphenols have been widely assumed to be beneficial to human health. Polyphenols are commercially prepared and used as functional foods. We reported that ferulic acid, which is widely used as a functional food, affects the transport of clinical agents. The major dose-limiting toxicity after administration of irinotecan hydrochloride, 7-ethyl-10-(4-[1-piperidino]-1-piperidino)-carbonyloxycamptothecin (CPT-11) is severe diarrhea. We have found that a specific transport system mediates the uptake of active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38) across the apical membrane in Caco-2 cells. Baicalin and sulfobromophthatlein inhibit this transporter. Inhibition of this transporter would be a useful means for reducing late-onset diarrhea.

Silica-supported 4-pyrrolidinopyridinium iodide was prepared by quaternization of 4-pyrrolidinopyridine with silica-supported alkyl iodide. The pyrrolidinopyridinium structure on the silica surface was confirmed by solid-state 13C CP MAS NMR. The silica-supported 4-pyrrolidinopyridinium iodide showed excellent catalytic performances for transformations of various epoxides to cyclic carbonates under atmospheric pressure of carbon dioxide (CO2). The reactions took place without any solvents or additives other than the catalyst. The catalyst was reusable with retention of activity and selectivity. 1-n-Hexyl-4-pyrrolidinopyridinium as a homogeneous catalyst showed a lower catalytic performance than the supported catalyst. Bifunctional catalysis involving acidic surface silanol and the basic 4-pyrrolidinopyridinium iodide was proposed.

High temperature heat contents of the Cu–Zr system alloys were measured over temperature range from 880 to 1470 K using a drop calorimeter. The enthalpies of fusion of some solid compounds were determined by the heat content—temperature plots and the entropies of fusion were calculated. Enthalpies of mixing in the liquid Cu–Zr system were measured by high temperature reaction calorimetry in the concentration range of xZr = 0.182–0.667 at 1443 K. This system has negative enthalpies of mixing over the measured concentration range. The standard enthalpies of formation at 298.15 K of Cu9Zr2, Cu51Zr14, Cu8Zr3, Cu10Zr7 and CuZr2 compounds were determined from the obtained data for the heat contents and enthalpies of mixing. Based on the experimental data, published thermodynamic and phase diagram data, the Cu–Zr binary system was analyzed using Redlich–Kister polynomial equation. The thermodynamic properties and the phase diagram calculated from the optimized parameters agree well with the experimental data.