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51.
Masaki Asai Yukiko Takemoto Ayaka Deguchi Yasunao Hattori Hidefumi Makabe 《Tetrahedron: Asymmetry》2017,28(11):1582-1586
The synthesis of (+)-monomorine I, an indolizidine alkaloid isolated from Monomorium pharaonis, has been achieved. The 2,6-cis-piperidine ring moiety of (+)-monomorine I was constructed using diastereoselective aminopalladation. Chain elongation via cross-metathesis using Hoveyda-Grubbs 2nd catalyst followed by deprotection of the Cbz group and cyclic reductive hydroamination afforded (+)-monomorine I. 相似文献
52.
Green,Multi‐Gram One‐Step Synthesis of Core–Shell Nanocomposites in Water and Their Catalytic Application to Chemoselective Hydrogenations
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Teppei Urayama Dr. Takato Mitsudome Dr. Zen Maeno Dr. Tomoo Mizugaki Prof. Dr. Koichiro Jitsukawa Prof. Dr. Kiyotomi Kaneda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):17962-17966
We devise a new and green route for the multi‐gram synthesis of core–shell nanoparticles (NPs) in one step under organic‐free and pH‐neutral conditions. Simply mixing core and shell metal precursors in the presence of solid metal oxides in water allowed for the facile fabrication of small CeO2‐covered Au and Ag nanoparticles dispersed on metal oxides in one step. The CeO2‐covered Au nanoparticles acted as a highly efficient and reusable catalyst for a series of chemoselective hydrogenations, while retaining C=C bonds in diverse substrates. Consequently, higher environmental compatibility and more efficient energy savings were achieved across the entire process, including catalyst preparation, reaction, separation, and reuse. 相似文献
53.
S.A. Bystrov H. Honma V.I. Ivanov J. Koreeda K. Maeno F.V. Shugaev H. Yanagisawa 《Shock Waves》1998,8(3):183-189
Using a diffraction approach the convolution-type integral equation for the laser schlieren signal created by an arbitrary
disturbance at low pressure, where refractive index of disturbance is close to unity, in a shock tube (thin optical layer)
has been deduced. In the equation electric circuit relaxation processes were taken into account by a response function. The
equation was solved with the aid of the regularization method worked out for ill-posed problems. The density structures of
the strong shock waves in air have numerically been reconstructed from experimental data ranging shock wave Mach number of
–30, and –30 Pa.
Received 7 April 1996 / Accepted 20 June 1996 相似文献
54.
A catalytic oxidation of p-alkoxyphenols was developed using tetrabutylammonium bromide (TBAB) and Oxone(?). The reaction of p-alkoxyphenol (1) with a catalytic amount of TBAB in the presence of Oxone(?) as a co-oxidant in acetonitrile-water (2 : 1) gave the corresponding p-quinone (2) in excellent yield without special treatment. 相似文献
55.
Joshua Kyle Stanfield Keita Omura Ayaka Matsumoto Chie Kasai Hiroshi Sugimoto Yoshitsugu Shiro Yoshihito Watanabe Osami Shoji 《Angewandte Chemie (International ed. in English)》2020,59(19):7611-7618
Despite CYP102A1 (P450BM3) representing one of the most extensively researched metalloenzymes, crystallisation of its haem domain upon modification can be a challenge. Crystal structures are indispensable for the efficient structure‐based design of P450BM3 as a biocatalyst. The abietane diterpenoid derivative N‐abietoyl‐l ‐tryptophan (AbiATrp) is an outstanding crystallisation accelerator for the wild‐type P450BM3 haem domain, with visible crystals forming within 2 hours and diffracting to a near‐atomic resolution of 1.22 Å. Using these crystals as seeds in a cross‐microseeding approach, an assortment of P450BM3 haem domain crystal structures, containing previously uncrystallisable decoy molecules and diverse artificial metalloporphyrins binding various ligand molecules, as well as heavily tagged haem‐domain variants, could be determined. Some of the structures reported herein could be used as models of different stages of the P450BM3 catalytic cycle. 相似文献
56.
A 3‐Pyridyl‐5,15‐Diazaporphyrin Nickel(II) Complex as a Bidentate Metalloligand for Transition Metals
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Ayaka Yamaji Prof. Dr. Ji‐Young Shin Prof. Dr. Yoshihiro Miyake Prof. Dr. Hiroshi Shinokubo 《Angewandte Chemie (International ed. in English)》2014,53(50):13924-13927
3‐Pyridyl‐5,15‐diazaporphyrin nickel(II) serves as a bidentate metalloligand for platinum(II), ruthenium(II), and rhenium(I) metal centers. Single‐crystal X‐ray diffraction analysis of these metal complexes unambiguously reveals the presence of a dative bond between the outer metal center and the meso‐nitrogen atom. The UV/Vis absorption spectra of the complexes show substantially red‐shifted bands which are perturbed by outer‐metal coordination. This is due to the contribution of metal‐to‐ligand charge transfer interactions. 相似文献
57.
C.E. Gough R.J. OrmenoA. Sibley M. HeinS. NishiZaki Y. Maeno 《Journal of Physics and Chemistry of Solids》2002,63(12):2187-2193
A hollow dielectric resonator technique has been developed for accurate measurements of the complex microwave surface impedance of novel superconductors from 2 to 20 GHz down to 100 mK. Illustrative measurements of the antiferromagnetic ordering and spin-dynamics of Gd ions in GdBa2Cu3O7 and of microwave penetration and losses in MgB2 wires and high quality single crystals of Sr2RuO4 are presented. Measurements on Sr2RuO4 imply an unchanged electron relaxation time τ on entering the superconducting state, a power law temperature dependence of the normal state fraction implying nodes in the superconducting order parameter, and residual low temperature losses on increasing frequency. 相似文献
58.
Mei Itabashi Chigen Tsukamoto Ayaka Kurosaka Panneerselvam Krishnamurthy Tai-Sun Shin Seung Hwan Yang 《液相色谱法及相关技术杂志》2016,39(14):640-646
New saponin components, Sg-6 saponins, have been recently reported from the seeds of wild soybean (Glycine soja) which may have specific health benefits. To evaluate the possible health benefits, a large amount of Sg-6 saponins are needed, but general group A acetyl saponins and new Sg-6 saponins are eluted in overlapping peaks by ordinal preparative high-performance liquid chromatography and/or open column methods. A new method is proposed in this report. This method includes (1) deacetylation of group A acetyl saponins in alkali condition with KOH, (2) precipitation of Sg-6 saponins in acid condition with HCl, (3) recovery of Sg-6 saponins with aqueous methanol from the precipitate, and (4) elution of Sg-6 saponins by preparative reverse-phase open column. With this method, from 450?g of wild soybean whole seed powder, about 1?g of Sg-6 saponins (mixture of six components) was clearly separated from other saponins with 61% recovery. 相似文献
59.
Centrifugal partition chromatography (CPC) was applied to separate amphiphilic glycolipids and pseudo-glycolipids synthesized by using cells. Neutral and acidic lipid fractions were isolated by CPC under suitable conditions respectively. Separation of neutral lipid, Gb3-type and Gb4-type oligosaccharide synthesized by using cells, was performed with a two-phase solvent system composed of chloroform-methanol-water at a volume ratio of 5:6:4. On the other hand, separation of acidic lipid, GM3-type oligosaccharide synthesized by using cells, and ganglioside extracted from rat brain were performed with a two-phase solvent system composed of butanol-ethanol-1% acetic acid at a volume ratio of 4:1:5. 8.3mg of Gb3 analogue, 5.1mg of Gb4 analogue, and 19.5mg of GM3 analogue were purified from 3.2l of culture medium obtained by incubation of African green-monkey kidney (Vero) cells with 50 microM n-dodecyl beta-lactoside using CPC. 相似文献
60.
Ito Y Heydari M Hashimoto A Konno T Hirasawa A Hori S Kurita K Nakajima A 《Langmuir : the ACS journal of surfaces and colloids》2007,23(4):1845-1850
A hydrophobic to hydrophilic gradient surface was prepared using the tuned photodegradation of an alkylsilane self-assembled monolayer (SAM) using irradiation of vacuum ultraviolet light (wavelength=172 nm). The water contact angle on the photodegraded SAM surface was adjusted using the intensity and time photoirradiation parameters. The formation of a gradient was confirmed by fluorescent labeling. The water drop moved from the hydrophobic to hydrophilic surface with a velocity that depended on the gradient. The higher the gradient, the faster the water moved. For the first time, we have prepared a gradient surface using photodegradation where the movement of a water drop was regulated by the degree of gradation. Considering that the photodegradation technique can be applied to various surfaces and to lithography, this technique will be useful for various material surfaces. 相似文献