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71.
Sayaka Taji Takeshi Yamada Yasuko In Shun‐ichi Wada Yoshihide Usami Kazuo Sakuma Reiko Tanaka 《Helvetica chimica acta》2007,90(11):2047-2057
Three new lanostane‐type triterpenoids, inonotsulides A, B, and C ( 1 – 3 , resp.) were isolated from the sclerotia of Inonotus obliquus (Pers .: Fr.) (Japanese name: Kabanoanatake; Russian name: Chaga). Their structures were determined to be (20R,24S)‐3β,25‐dihydroxylanost‐8‐en‐20,24‐olide ( 1 ), (20R,24R)‐3β,25‐dihydroxylanost‐8‐en‐20,24‐olide ( 2 ), and (20R,24S)‐3β,25‐dihydroxylanosta‐7,9(11)‐dien‐20,24‐olide ( 3 ) on the basis of chemical transformation, NMR spectroscopy including 1D and 2D (1H,1H‐COSY, NOESY, HMQC, HMBC), EI‐MS, and single‐crystal X‐ray analysis. 相似文献
72.
A residual-host prepared by thermal removal of naphthalene (NA) from the inclusion compound [Ni(SCN)(2)(isonicotinic acid)(2)]·(NA)(0.5) was found to function as an adsorbent for aromatic molecules and exhibit method-dependent selectivity. 相似文献
73.
Yuka Wakata Mika Tokumoto Ryo Horiguchi Katsutoshi Ishikawa Yoshitaka Nagahama Toshinobu Tokumoto 《BMC biochemistry》2004,5(1):18
Background
The 26S proteasome is the proteolytic machinery of the ubiquitin-dependent proteolytic system responsible for most of the regulated intracellular protein degradation in eukaryotic cells. Previously, we demonstrated meiotic cell cycle dependent phosphorylation of α4 subunit of the 26S proteasome. In this study, we analyzed the changes in the spotting pattern separated by 2-D gel electrophoresis of α subunits during Xenopus oocyte maturation. 相似文献74.
Ryo Akiyama 《Journal of organometallic chemistry》2004,689(23):3806-3809
A novel polymer incarcerated Pd catalyst (PI Pd 7c) was synthesized from amide-containing polymer 6b, and this catalyst was shown to be effective in amidocarbonylation, which is a versatile one-pot method for the preparation of N-acyl-α-amino acids. The reactions proceeded smoothly with a wide variety of substrates, and no leaching of the Pd metal to the reaction mixture was detected. 相似文献
75.
Fujii S Mochizuki M Aono K Hamasaki S Murakami R Nakamura Y 《Langmuir : the ACS journal of surfaces and colloids》2011,27(21):12902-12909
Polystyrene (PS) latex particles carrying pH-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) hair (PDEA-PS particles) were synthesized by dispersion polymerization and characterized in terms of diameter, diameter distribution, morphology, chemical composition, surface chemistry, and pH-response using scanning electron microscopy (SEM), elemental microanalysis, (1)H nuclear magnetic resonance spectroscopy, the laser diffraction method, and zeta potential measurements. The hairy particles can act as pH-responsive stabilizers of aqueous foams by adsorption at the air-water surface. Above pH 8.0, where particles have nonprotonated PDEA hair, which is relatively hydrophobic, particle-stabilized foams are stable for at least 1 month. Optical microscopy and SEM confirmed that flocculated PDEA-PS latex particles were adsorbed at the air-water interface and stabilized the aqueous foams. At pH 6.1 and 7.1, relatively stable foams can be prepared that remain stable for at least 24 h. SEM studies indicated that the PDEA-PS particles were adsorbed at the air-water interface as a monolayer at pH 6.1. At pH 5.1 and 3.1, where the particles have cationic water-soluble PDEA hairs with hydrophilic character, no foam was formed. Rapid defoamation can be induced by lowering the solution pH; the addition of acid caused the in situ protonation of 2-(diethylamino)ethyl methacrylate residues, which impart water-soluble hydrophilic character to the PDEA hair, and the PDEA-PS particles desorbed from the air-water interface. The foaming and defoaming cycles could be repeated at least five times. 相似文献
76.
77.
Ryo Kimura Hikaru Kuramochi Pengpeng Liu Takuya Yamakado Atsuhiro Osuka Tahei Tahara Shohei Saito 《Angewandte Chemie (International ed. in English)》2020,59(38):16430-16435
Flapping fluorophores (FLAP) with a flexible 8π ring are rapidly gaining attention as a versatile photofunctional system. Here we report a highly photostable “flapping peryleneimide” with an unprecedented fluorogenic mechanism based on a bent‐to‐planar conformational change in the S1 excited state. The S1 planarization induces an electronic configurational switch, almost quenching the inherent fluorescence (FL) of the peryleneimide moieties. However, the FL quantum yield is remarkably improved with a prolonged lifetime upon a slight environmental change. This fluorogenic function is realized by sensitive π‐conjugation design, as a more π‐expanded analogue does not show the planarization dynamics. With strong visible‐light absorption, the FL lifetime response synchronized with the flexible flapping motion is useful for the latest optical techniques such as FL lifetime imaging microscopy (FLIM). 相似文献
78.
A Programmable Signaling Molecular Recognition Nanocavity Prepared by Molecular Imprinting and Post‐Imprinting Modifications 下载免费PDF全文
Ryo Horikawa Dr. Hirobumi Sunayama Dr. Yukiya Kitayama Dr. Eri Takano Prof. Dr. Toshifumi Takeuchi 《Angewandte Chemie (International ed. in English)》2016,55(42):13023-13027
Inspired by biosystems, a process is proposed for preparing next‐generation artificial polymer receptors with molecular recognition abilities capable of programmable site‐directed modification following construction of nanocavities to provide multi‐functionality. The proposed strategy involves strictly regulated multi‐step chemical modifications: 1) fabrication of scaffolds by molecular imprinting for use as molecular recognition fields possessing reactive sites for further modifications at pre‐determined positions, and 2) conjugation of appropriate functional groups with the reactive sites by post‐imprinting modifications to develop programmed functionalizations designed prior to polymerization, allowing independent introduction of multiple functional groups. The proposed strategy holds promise as a reliable, affordable, and versatile approach, facilitating the emergence of polymer‐based artificial antibodies bearing desirable functions that are beyond those of natural antibodies. 相似文献
79.
In the long history regarding the development of the transition metal-catalyzed reactions, almost all ligands in metals are classified as the covalent X-type and/or dative L-type ligands. Therefore, exploring the reactivity of the metal complexes bearing the σ-acceptor, i.e., the Z-ligand, is required. This digest briefly describes our recent results regarding 1) the syntheses of gold complexes featuring the Z-type ligand, and 2) their catalytic reactions, which would be speculated that the electron-withdrawing effect of the Z-ligand on the neighboring gold activated the catalytic reactivity due to the increase in the Lewis acidity. 相似文献
80.
Ohtani R Yoneda K Furukawa S Horike N Kitagawa S Gaspar AB Muñoz MC Real JA Ohba M 《Journal of the American Chemical Society》2011,133(22):8600-8605
Precise control of spin transition temperature (T(c)) is one of the most important challenges in molecular magnetism. A Hofmann-type porous coordination polymer {Fe(pz)[Pt(II)(CN)(4)]} (1; pz = pyrazine) exhibited cooperative spin transition near room temperature (T(c)(up) = 304 K and T(c)(down) = 284 K) and its iodine adduct {Fe(pz)[Pt(II/IV)(CN)(4)(I)]} (1-I), prepared by oxidative addition of iodine to the open metal sites of Pt(II), raised the T(c) by 100 K. DSC and microscopic Raman spectra of a solid mixture of 1-I and 1 revealed that iodine migrated from 1-I to 1 through the grain boundary after heating above 398 K. We have succeeded in precisely controlling the iodine content of {Fe(pz)[Pt(CN)(4)(I)(n)]} (1-In; n = 0.0-1.0), which resulted in consecutive modulation of T(c) in the range 300-400 K while maintaining the hysteresis width. Furthermore, it was demonstrated that iodine migration in the solid mixture was triggered by the spin transition of 1-I. The magnetically bistable porous framework decorating guest interactive open-metal-site in the pore surface makes it possible to modulate T(c) ad arbitrium through unique postsynthetic method using iodine migration. 相似文献