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1.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
2.
Direct Addition of Amides to Glycals Enabled by Solvation‐Insusceptible 2‐Haloazolium Salt Catalysis
Yuya Nakatsuji Yusuke Kobayashi Yoshiji Takemoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(40):14253-14257
The direct 2‐deoxyglycosylation of nucleophiles with glycals leads to biologically and pharmacologically important 2‐deoxysugar compounds. Although the direct addition of hydroxyl and sulfonamide groups have been well developed, the direct 2‐deoxyglycosylation of amide groups has not been reported to date. Herein, we show the first direct 2‐deoxyglycosylation of amide groups using a newly designed Brønsted acid catalyst under mild conditions. Through mechanistic investigations, we discovered that the amide group can inhibit acid catalysts, and the inhibition has made the 2‐deoxyglycosylation reaction difficult. Diffusion‐ordered two‐dimensional NMR spectroscopy analysis implied that the 2‐chloroazolium salt catalyst was less likely to form aggregates with amides in comparison to other acid catalysts. The chlorine atom and the extended π‐scaffold of the catalyst played a crucial role for this phenomenon. This relative insusceptibility to inhibition by amides is more responsible for the catalytic activity than the strength of the acidity. 相似文献
3.
Guangrui Chen Yuxing Yan Dr. Jie Wang Prof. Yong Sik Ok Guiyuan Zhong Prof. Bu Yuan Guan Prof. Yusuke Yamauchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19831-19836
Mesoporous core–shell nanostructures with controllable ultra-large open channels in their nanoshells are of great interest. However, soft template-directed cooperative assembly to mesoporous nanoshells with highly accessible pores larger than 30 nm, or even above 50 nm into macroporous range, remains a significant challenge. Herein we report a general approach for precisely tailored coating of hierarchically macro-/mesoporous polymer and carbon shells, possessing highly accessible radial channels with extremely wide pore size distribution from ca. 10 nm to ca. 200 nm, on diverse functional materials. This strategy creates opportunities to tailor the interfacial assembly of irregular mesostructured nanounits on core materials and generate various core–shell nanomaterials with controllable pore architectures. The obtained Fe,N-doped macro-/mesoporous carbon nanoshells show enhanced electrochemical performance for the oxygen reduction reaction in alkaline condition. 相似文献
4.
5.
The potential of an N-Troc-protected sialic acid donor, equipped with phenylsulfenyl functionality as a leaving group, has been explored. As a result, the entitled donor was proven to be highly reactive and to have broad applicability toward the synthesis of variant sialo-glycans, which have N-glycolyl, de-N-acetyl, 1,5-lactam and 8-O-sulfo sialic acid analogs. 相似文献
6.
High-resolution vibrational electron energy loss spectroscopy, low-energy electron diffraction and Auger electron spectroscopy have been used to study the interactions of nitrogen with the Pd(110) surface. At 120 K, N2 is chemisorbed molecularly on the Pd(110) surface, and the (2 × 1)-N2 structure is formed. Most probably, the N2 molecules are chemisorbed in the on-top sites of the bulk-like Pd(110) surface in the upright-linear structure. The Pd---N2 bond energy is estimated to be ˜ 6 kcal/mol. The Pd---N2 and N---N stretching vibrations of N2 admolecules on Pd(110) are observed at 30 and 278 meV, respectively. The primary-energy dependence and angle dependence of their excitation cross sections agree reasonably well with the prediction of the dipole theory. The electron beam-induced effects are briefly discussed. 相似文献
7.
(Triisopropylsilyl)acetaldehyde dimethyl acetal (TIPS-ADMA) was synthesized from chlorotriisopropylsilane in three steps. Cyclic and acyclic 1,2-diols can be transformed to (triisopropylsilyl)ethylidene acetals (TIPS-AA). Removal of the acetal by LiBF4 regenerates the starting diol in excellent yield even in the presence of an acetonide of 1,2-diol. The TIPS-AA group can survive under the deprotection conditions of the acetonide in acetic acid at 80 °C. Selective protection of 2,3- and 4,6-diols for O-methyl d-mannoside with TIPS-ADMA and selective deprotection of the acetals have been achieved. 相似文献
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9.
Shibuya H Kitamura C Maehara S Nagahata M Winarno H Simanjuntak P Kim HS Wataya Y Ohashi K 《Chemical & pharmaceutical bulletin》2003,51(1):71-74
The microbial transformation of four Cinchona alkaloids (quinine, quinidine, cinchonidine, and cinchonine) by endophytic fungi isolated from Cinchona pubescens was investigated. The endophytic filamentous fungus Xylaria sp. was found to transform the Cinchona alkaloids into their 1-N-oxide derivatives. 相似文献
10.
K. Komura K. Komura Y. Kuwahara Y. Kuwahara T. Abe T. Abe K. Tanaka K. Tanaka Y. Murata Y. Murata M. Inoue M. Inoue 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(2):511-516
Summary Extremely low activity levels of cosmic ray induced nuclides have been measured in freshly precipitated rainwater by quick
chemical separation coupled with ultra low background gamma-spectrometry. The nuclides detected were 38S (T1/2 = 2.83 h)-38Cl (37.2 m), 39Cl (55.6 m), 24Na (14.96 h), 28Mg (20.9 h), 7Be (53.3 d) and 22Na (2.602 y). The number of atoms in rain water were evaluated to be ranging from 400-1900 l-1 for 39Cl (n = 6, mean: 1200), 30-1500 l-1 for 24Na (n = 16, mean: 520), 80-600 l-1 for 28Mg (n = 13, mean: 260), 1 . 106-4 . 107 l-1 for 7Be (n = 16, mean: 7 . 106) and 2 . 103-1 . 105 l-1 for 22Na (n = 9, mean: 2 . 104). Measurements of activity levels and activity ratios of short-lived cosmic-ray induced short-lived nuclides will open new
method to understand atmospheric processes occurred at the altitude of rain cloud. 相似文献