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61.
Ariaki Murata Ryota Akaike Tatsuya Kawahashi Ryo Tsuchiya Hiroyuki Takemoto Toshiyuki Ohnishi Yasushi Todoroki Nobuyuki Mase Mineyuki Yokoyama Kazuteru Takagi Peter Winterhalter Naoharu Watanabe 《Tetrahedron》2014
A flower-inducing compound, LDS1, was isolated from a free-floating aquatic plant, Lemna paucicostata. The chemical structure and the absolute stereochemistry of LDS1 were determined as (9R,13R,11E,15Z)-9,13-dihydroxy-10-oxooctadeca-11,15-dienoic acid for its most abundant diastereomer. LDS1 was enzymatically produced when the plant was exposed to drought stress, and induced flowering at a concentration of 10 nM. 相似文献
62.
Toshiyuki Moriuchi Toshikazu Hirao 《Journal of inclusion phenomena and macrocyclic chemistry》2012,74(1-4):23-40
This review describes an outline of dipeptide-induced chirality organization by using molecular scaffolds. A variety of ferrocene-dipeptide conjugates as bioorganometallics are designed to induce chirality-organized structures of peptides. The ferrocene serves as a reliable organometallic scaffold with a central reverse-turn unit for the construction of protein secondary structures via intramolecular hydrogen bondings, wherein the attached dipeptide strands are constrained within the appropriate dimensions. Another interesting feature of ferrocene-dipeptide conjugates is their strong tendency to self-assemble through contribution of available hydrogen bonding sites for helical architectures in solid states. Symmetrical introduction of two dipeptide chains into a urea molecular scaffold is performed to induce the formation of the chiral hydrogen-bonded duplex, wherein each hydrogen-bonded duplex is connected by continuous intermolecular hydrogen bonds to form a double helix-like arrangement. 相似文献
63.
Makoto Nonomura Fumio Nakagawa Shinya Mizusawa Takashi Ohno Hiroyuki Kobayashi Toshiyuki Hobo 《International journal of environmental analytical chemistry》2013,93(4):371-379
Abstract Although cyanide compounds are not incorporated in photographic processing solutions, false detection of cyanide ion is often encountered during the determination of total cyanide by various standardized methods such as ISO, ANSI and JIS. Various organic compounds and nitrogen compounds in the processing solutions were examined because of this false detection. The results suggest that hydrogen cyanide is formed by a reaction between these compounds during the distillation process for the separation of total cyanide, even though ISO, ANSI and JIS were used. The results support the following three mechanisms of cyanide formation involved in the process: (1) Hydroxylammonium salts reacts with another ingredient, formaldehyde, to form formaldoxime, which then decomposes to HCN. (2) Hydroxylammonium is oxidized by air to form nitrite ion, which subsequently reacts with organic compounds such as aminocarboxylic acids and aromatic amines (the colour-developing agent) to form HCN. (3) Potassium permanganate oxidizes aromatic amines to form HCN. 相似文献
64.
Sulfonylurea derivatives including useful antidiabetics (Tolbutamide, Chlorpropamide) were synthesized in good yields from benzene-sulfonamides with thiocarbamates in the presence of DBU. Thiocarbamates were prepared by the selenium-assisted carbonylation of primary amines with carbon monoxide, sulfur, and methyl iodide under mild conditions. 相似文献
65.
Alkylesters of orthophosphoric acids have been used for alkylation of phenols1, anilines2, and nitrogen heterocyclic compounds.3 However, no example is reported on their use as an alkoxylating agent for aromatic amines. We have found that alkyl phosphates can act as alkoxylating agents for aromatic diamines in the presence of H2O or aqueous H3PO4. We now report the one-step dialkoxylation of aromatic diamines such as diaminoanthracene and -naphthalene by trialkyl phosphates. 相似文献
66.
Concomitant supplementation of a histone deacetylase inhibitor, suberoylanilide hydroxamic acid, and a DNA methyltransferase inhibitor, 5-azacytidine, to the culture medium of a plant endophytic fungus, Pestalotiopsis acaciae, dramatically altered its metabolic profiles. As a result, three novel aromatic compounds, 2′-hydroxy-6′-hydroxymethyl-4′-methylphenyl-2,6-dihydroxy-3-(2-isopentenyl)benzoate (1), 4,6-dihydroxy-7-hydroxymethyl-3-methylcoumarin (2) and 4,6-dihydroxy-3,7-dimethylcoumarin (3), were isolated, along with five known polyketides, endocrocin (4), pestalotiollide B (5), pestalotiopyrone G (6), scirpyrone A (7) and 7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone (8). 相似文献
67.
Toshiyuki Fujii Frédéric Moynier Arnaud Agranier Emmanuel Ponzevera Minori Abe Akihiro Uehara Hajimu Yamana 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):261-265
Environmental transport of Tl is affected by redox reaction between Tl(I) and Tl(III) and ligand exchange reactions of them. In order to deepen the knowledge of Tl chemistry, we investigated fractionation of Tl stable isotopes (203Tl and 205Tl) in a chemical exchange system. Tl isotopes were fractionated in a liquid–liquid extraction system, in which aqueous and organic phases are hydrochloric acid solution and dichloroethane including a crown ether, respectively. After purification by ion-exchange chemistry, the isotope ratio of 205Tl/203Tl in equilibrated aqueous phase was measured precisely by multiple-collector–inductively-coupled-plasma–mass-spectrometry. A large isotope fractionation >1 ‰ was found. Electronic structures of possible Tl species (hydrated Tl+, Tl3+, and Tl chlorides) were calculated by ab initio methods, and the isotope fractionation factor was theoretically obtained. The isotope fractionation via intramolecular vibrations was calculated to be much smaller than the experimental result. The isotope fractionation via isotopic change in nuclear volume, named the nuclear field shift effect, was calculated to be >1 ‰ in Tl(I)–Tl(III) redox systems and/or ligand exchange systems of Tl(III). The nuclear field shift effect was found to be the major origin of Tl isotope fractionation. 相似文献
68.
Takashi Kato Toshiyuki Uryu Fumiko Kaneuchi Chihiro Jin Jean M. J. Fréchet 《Liquid crystals》2013,40(5):1311-1317
Abstract The stability of a hydrogen-bonded complex built through inter-molecular hydrogen bonding between carboxylic acid and pyridine fragments has been examined using infrared spectroscopy. Infrared spectra as a function of temperature have been recorded for the 1:1 complex of 4-hexyloxybenzoic acid and trans-4-propoxy-4′-stilbazole from the crystalline state to the isotropic state. A dependence of the stability of the hydrogen bond on molecular orientation is observed clearly in the infrared spectra. The spectra also suggest that the hydrogen bond is an unionized type with a double minimum potential energy. 相似文献
69.
Photochromic acrylates containing both biphenylene and spiro-oxazine moieties with a chiral substituent and the related polymers were prepared and yielded photochromic chiral liquid crystalline systems. The photochromic acrylates containing both an undecamethylene group and a (2S, 3S)-2-chloro-3-methylpentanoyloxy group (A11SOP) or a (-)-menthoxyacetoxy group (A11SOM) gave a supercooled mesophase; the latter reflected right-handed visible light (blue colour) at room temperature. On the other hand, the photochromic acrylate containing both the (R)-(-)-2-methylpropylene and (2S, 3S)-2-chloro-3-methylpentanoyloxy groups (A3SOP) showed no mesophase. The related homopolymers, PA11SOP and PA11SOM, did not exhibit mesophases because of steric hindrance between the side groups of the polymers. However, only PA11SOM exhibited shear-induced birefringence under 100-104°C. Several copolymers consisting of the nematogenic monomer, 4-[4-(6-acryloyloxyhexyloxy)benzoyloxy]benzonitrile (A6CN), and A11SOP or A11SOM possessed a smectic phase due to reduction of the steric hindrance between the potentially smectogenic A11SOP or A11SOM moieties. 相似文献