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991.
A novel amphiphilic supramolecular polymer (ASP) with rigid linear main chain has been constructed by the co-assembly of a rigid amphiphilic monomer and cucurbit[8]uril (CB[8]) in water, driven by CB[8]-based host-guest interactions. The ASP could further self-assemble into well-defined architectures including nanotubes and 2D films, depending on its concentration. Moreover, pH-responsive behavior of the ASP was also observed. 相似文献
992.
Yongxing Tang Yajun Yu Xinyu Wei Jin Yang Yeting Zhu Yun-Hui Zhao Zilong Tang Zhihua Zhou Xiaofang Li Xianyong Yu 《Tetrahedron letters》2019,60(43):151187
A novel 6-endo-dig cyclization followed by oxidation/elimination of o-alkynylarylaldimines with 4-hydroxybenzylamine was developed for preparation of isoquinolines. The intermediates of this tandem reaction were monitored by mass spectroscopy (MS) to confirm the reaction pathway. This methodology was further applied to the design and synthesis of a novel ratiometric chemosensor for determination of fluoride. 相似文献
993.
994.
995.
Lena Scherthan Sebastian F. M. Schmidt Hendrik Auerbach Tim Hochdrffer Juliusz A. Wolny Wenli Bi Jiyong Zhao Michael Y. Hu Tom Toellner E. Ercan Alp Dennis E. Brown Christopher E. Anson Annie K. Powell Volker Schünemann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3482-3487
Time‐domain synchrotron Mössbauer spectroscopy (SMS) based on the Mössbauer effect of 161Dy has been used to investigate the magnetic properties of a DyIII‐based single‐molecule magnet (SMM). The magnetic hyperfine field of [Dy(Cy3PO)2(H2O)5]Br3?2 (Cy3PO)?2 H2O?2 EtOH is with B0=582.3(5) T significantly larger than that of the free‐ion DyIII with a 6H15/2 ground state. This difference is attributed to the influence of the coordinating ligands on the Fermi contact interaction between the s and 4f electrons of the DyIII ion. This study demonstrates that 161Dy SMS is an effective local probe of the influence of the coordinating ligands on the magnetic structure of Dy‐containing compounds. 相似文献
996.
Sheng‐Li Hou Jie Dong Xiao‐Lei Jiang Zhuo‐Hao Jiao Bin Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(2):587-591
Cyclization of propargylic alcohols with CO2 is an important reaction in industry, and noble‐metal catalysts are often employed to ensure the high product yields under environmentally friendly conditions. Herein a porous noble‐metal‐free framework 1 with large 1D channels of 1.66 nm diameter was synthesized for this reaction. Compound 1 exhibits excellent acid/base stability, and is even stable in corrosive triethylamine for one month. Catalytic studies indicate that 1 is an effective catalyst for the cyclization of propargylic alcohols and CO2 without any solvents under mild conditions, and the turnover number (TON) can reach to a record value of 14 400. Furthermore, this MOF catalyst also has rarely seen catalytic activity when the biological macromolecule ethisterone was used as a substrate. Mechanistic studies reveal that the synergistic catalytic effect between CuI and InIII plays a key role in the conversion of CO2. 相似文献
997.
Changgui Zhao Daniel A. Glazier Daoshan Yang Dan Yin IIia A. Guzei Michael M. Aristov Peng Liu Weiping Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(3):897-901
We have developed the first intermolecular hetero‐[5+2] cycloaddition reaction between oxidopyrylium ylides and cyclic imines with excellent control of regio‐ and stereoselectivity. Surprisingly, divergent stereochemistry was observed depending on the substitution pattern of the oxidopyrylium ylide. This new reaction provides quick access to highly substituted nitrogen‐containing seven‐membered rings—azepanes. Notably, a broad range of oxidopyrylium ylides and cyclic imines participate in this novel hetero‐[5+2] cycloaddition reaction and the cycloadducts can be readily transformed into the core skeletons of bioactive natural products. DFT calculations revealed that the cycloaddition proceeds through a stepwise pathway and the imine nitrogen atom serves as the nucleophile to initiate the cycloaddition. 相似文献
998.
Chengcheng Zhao Zheming Ying Xiaojun Tao Mingyue Jiang 《Natural product research》2018,32(13):1548-1553
A new lactam alkaloid named oleraciamide D (1), indentified as (5R)-4-(3-methoxy-4-hydroxyphenyl)-5-(4-hydroxyphenyl)-5,6-dihydropyridin-2(1H)-one, together with five known compounds, indole-3-aldehyde (2), portulacatone (3), N-trans-feruloyloctopamine (4), N-trans-feruloyl-3′-O-methyldopamine (5) and N-trans-feruloyltyramine (6) were isolated from Potulaca oleracea L. Among them, indole-3-aldehyde (2) was isolated from the medicine for the first time. The structure of the new alkaloid was elucidated via UHPLC-ESI-Q-TOF/MS, 1D NMR and 2D NMR. The five known compounds were established by comparing the 1H-NMR and 13C NMR with the reported literature. Oleraciamide D (1) showed cytotoxicity against SH-SY5Y cells when concentration at 50 uM by CCK-8 method. 相似文献
999.
Long Zhilin Liu Wei Zhong Ming Zhang Yun Zhao Mingshengzi Liao Guangkai Chen Zhuo 《Journal of Thermal Analysis and Calorimetry》2018,132(3):1645-1660
Journal of Thermal Analysis and Calorimetry - A new criterion or parameter χ given by $$\left( {\frac{{T_{\text{x}} - T_{\text{g}} }}{{T_{\text{l}} - T_{\text{x}} }}} \right) \times \left(... 相似文献
1000.
Jing Qi Feng‐Lian Zhang Ji‐Kang Jin Qiang Zhao Bin Li Lin‐Xuan Liu Yi‐Feng Wang 《Angewandte Chemie (International ed. in English)》2020,59(31):12876-12884
Radical borylation using N‐heterocyclic carbene (NHC)‐BH3 complexes as boryl radical precursors has emerged as an important synthetic tool for organoboron assembly. However, the majority of reported methods are limited to reaction modes involving carbo‐ and/or hydroboration of specific alkenes and alkynes. Moreover, the generation of NHC‐boryl radicals relies principally on hydrogen atom abstraction with the aid of radical initiators. A distinct radical generation method is reported, as well as the reaction pathways of NHC‐boryl radicals enabled by photoredox catalysis. NHC‐boryl radicals are generated via a single‐electron oxidation and subsequently undergo cross‐coupling with the in‐situ‐generated radical anions to yield gem‐difluoroallylboronates. A photoredox‐catalyzed radical arylboration reaction of alkenes was achieved using cyanoarenes as arylating components from which elaborated organoborons were accessed. Mechanistic studies verified the oxidative formation of NHC‐boryl radicals through a single‐electron‐transfer pathway. 相似文献