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981.
The Mitsunobu reaction is a well-established fundamental reaction and has been widely applied in organic synthesis. In this
paper, under Mitsunobu conditions dehydration proceeds between (2-chloroquinolin-3-yl)methanol and nitrogen heterocyclic compounds
such as quinazolinone, pyrimidone, 2-oxoquinoline in dry THF in the presence of triethylamine, triphenylphosphane and diethyl
azodicarboxylate to give the corresponding products. As part of our recent research, we attempted to couple two N-heterocyclic compounds under Mitsunobu reaction conditions to provide efficient building blocks for natural product synthesis. 相似文献
982.
This report successfully demonstrates the synthesis and application of palladium stearates. It was found that the branching of the carboxylate anion of metal precursors could influence the size and shape of palladium nanoparticles (PdNPs). Worm‐like nanowires were formed when using the branched isomer palladium isostearate (PdISt2), while triangular nanoparticles were produced in a majority when using the normal form: palladium stearate (PdSt2). Furthermore, when applying CO2 to the system, both types of PdNPs transformed into more spherical shapes with smaller sizes. The formation of carbamates from the amine stabilizer with CO2 could prevent the further growth and aggregation of PdNPs. The PdNPs were tested as catalysts for the hydrogenation of styrene, and higher catalytic activities were achieved with PdNPs that were prepared with the assistance of CO2. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
983.
Su Jung Noh Yasuyoshi Miyamoto Naoto Hayashi Ji Sung Lee Young Keun Kim 《Solid State Communications》2012,152(12):1004-1007
Magnetic domain wall behaviors in CoPt nanowires consisting of multiple pairs of notches were investigated by experimental measurements as well as by micromagnetic modeling. The nanowires were fabricated by ion-beam sputter deposition and e-beam lithography where one to three triangular shaped notches were installed at an interval of 1 μm. Based on the evaluated I–V characteristics, we observed that differential resistance curves showed two peaks with a local minimum at around zero current; the domain wall was trapped between the current ranges within these two peaks. As the number of notch was increased, the resistance of the nanowire became larger. 相似文献
984.
985.
986.
Dr. Lubna Ghani Dr. Seonghoon Kim Dr. Haoqing Wang Hyun Sung Lee Dr. Jonas S. Mortensen Dr. Satoshi Katsube Dr. Yang Du Dr. Aiman Sadaf Dr. Waqar Ahmed Prof. Bernadette Byrne Prof. Lan Guan Prof. Claus J. Loland Prof. Brian K. Kobilka Prof. Wonpil Im Prof. Pil Seok Chae 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(21):e202200116
Membrane proteins are of biological and pharmaceutical significance. However, their structural study is extremely challenging mainly due to the fact that only a small number of chemical tools are suitable for stabilizing membrane proteins in solution. Detergents are widely used in membrane protein study, but conventional detergents are generally poor at stabilizing challenging membrane proteins such as G protein-coupled receptors and protein complexes. In the current study, we prepared tandem triazine-based maltosides (TZMs) with two amphiphilic triazine units connected by different diamine linkers, hydrazine (TZM−Hs) and 1,2-ethylenediamine (TZM−Es). These TZMs were consistently superior to a gold standard detergent (DDM) in terms of stabilizing a few membrane proteins. In addition, the TZM−Es containing a long linker showed more general protein stabilization efficacy with multiple membrane proteins than the TZM−Hs containing a short linker. This result indicates that introduction of the flexible1,2-ethylenediamine linker between two rigid triazine rings enables the TZM−Es to fold into favourable conformations in order to promote membrane protein stability. The novel concept of detergent foldability introduced in the current study has potential in rational detergent design and membrane protein applications. 相似文献
987.
Wu Ming-Der Chen Jih-Jung Cheng Ming-Jen Hsieh Sung Yuan Chang Chih-Zen Kuo Yueh-Hsiung 《Chemistry of Natural Compounds》2022,58(5):839-841
Chemistry of Natural Compounds - A new cyclohexan-1-one, named xylariaone (1), was isolated from the fungal strain Xylaria sp. 12F0758. Its structure was elucidated by spectroscopic analyses,... 相似文献
988.
Shintarô Kuroki DongYoup Suh 《Proceedings of the Steklov Institute of Mathematics》2014,286(1):285-307
A complex projective tower, or simply a ?P-tower, is an iterated complex projective fibration starting from a point. In this paper we classify all six-dimensional ?P-towers up to diffeomorphism, and as a consequence we show that all such manifolds are cohomologically rigid, i.e., they are completely determined up to diffeomorphism by their cohomology rings. 相似文献
989.
990.
Keun Man SongJong Min Kim Bong Kyun KangChan Soo Shin Chul Gi KoBo Hyun Kong Hyung Koun ChoDae Ho Yoon Hogyoung Kim Sung Min Hwang 《Applied Surface Science》2012,258(8):3565-3570
Nonpolar a-plane GaN layers grown on r-plane sapphire substrates were examined by using a two-step growth process. The higher initial growth pressure for the nucleation layer resulted in the improved crystalline quality with lower density of both threading dislocations and basal stacking faults. This was attributed to the higher degree of initial roughening and recovery time via a growth mode transition from three-dimensional (3D) to quasi two-dimensional (2D) lateral growth. Using Hall-effect measurements, the overgrown Si doped GaN layers grown with higher initial growth pressure were found to have higher mobility. The scattering mechanism due to the dislocations was dominant especially at low temperature (<200 K) for the lower initial growth pressure, which was insignificant for the higher initial growth pressure. The temperature-dependent Hall-effect measurements for the Mg doped GaN with a higher initial growth pressure yielded the activation energy and the acceptor concentration to be 128 meV and 1.2 × 1019 cm−3, respectively, corresponding to about 3.6% of activation at room temperature. Two-step growth scheme with a higher initial growth pressure is suggested as a potential method to improve the performance of nonpolar a-plane GaN based devices. 相似文献