共查询到20条相似文献,搜索用时 31 毫秒
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Pavel . Volkov Nina I. Ivanova Nina K. Gusarova Boris G. Sukhov Kseniya O. Khrapova Lev E. Zelenkov Vladimir I. Smirnov Tatyana N. Borodina Tamara I. Vakul'skaya Spartak S. Khutsishvili Boris A. Trofimov 《Heteroatom Chemistry》2015,26(5):329-334
Secondary phosphine chalcogenides react with diacetone‐d‐glucose (DAG) in the system CCl4/Et3N (70°C, 4–24 h) to afford DAG chalcogenophosphinates in up to 79% yield, thus paving a short way to optically active chalcogenophosphinates with glucose moieties. As an example, a mild regioselective hydrolysis (70°C, aqueous MeCOOH) of DAG bis(2‐phenylethyl)selenophosphinate) obtained leads to monoacetone‐d‐glucose bis(2‐phenylethyl)selenophosphinate. 相似文献
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Xiaohui You Lin Qi Jia Zheng Wang Dai Yanchun Guo Yufen Zhao Shuxia Cao 《Heteroatom Chemistry》2015,26(2):168-174
The classical Atherton–Todd reaction has been successfully applied to the synthesis of pentacoordinate pyrospirophosphoranes containing a P‐O‐P bond under mild conditions. The absolute configurations of the products were confirmed by X‐ray diffraction analysis and spectroscopic identification. And 31P NMR chemical shifts of the products were correlated with stereochemistry. A possible mechanism for explaining the stereochemistry of the reaction was proposed, and it could well explain the results of the reactions of different pentacoordinate hydrospirophosphoranes. 相似文献
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《Helvetica chimica acta》2018,101(5)
We describe herein the first examples of Povarov reaction of tetrasubstituted cyclopentadienones in the preparation of quinoline compounds. Polycyclic compounds bearing tetrahydro‐3H‐cyclopenta[c]quinoline and dihydro‐1H‐cyclopenta[c]naphtha[2,3‐h]quinoline moieties have been synthesized by one pot reaction of tetrasubstituted cyclopentadienones with N‐arylamines and formaldehyde in the presence of trifluoroacetic acid. The control of the regioselectivity was total as well with symmetrical and non symmetrical cyclopentadienones. The X‐ray structures of new quinolines were reported. 相似文献
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Dehydrogenative Meyer–Schuster‐Like Rearrangement: A Gold‐Catalyzed Reaction Generating an Alkyne 下载免费PDF全文
M. Sc. Yang Yu M. Sc. Weibo Yang M. Sc. Daniel Pflästerer Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2014,53(4):1144-1147
Easily accessible propargylic esters are converted to the inverted alkynyl ketones in an oxidative gold‐catalyzed reaction. Gagosz’s catalyst in combination with PhI(OAc)2 is the best system for this conversion and 18 examples with yields up to 80 % are reported. The results indicate that the triple bond in the product is formed by elimination from a vinylgold intermediate. In a formal sense the new conversion overall is a dehydrogenative Meyer–Schuster rearrangement. 相似文献
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Kinetic Assay of the Michael Addition‐Like Thiol–Ene Reaction and Insight into Protein Bioconjugation 下载免费PDF全文
Fei‐He Ma Jia‐Liang Chen Qing‐Feng Li Hui‐Hui Zuo Feng Huang Prof. Xun‐Cheng Su 《化学:亚洲杂志》2014,9(7):1808-1816
The chemical modification of proteins is a valuable technique in understanding the functions, interactions, and dynamics of proteins. Reactivity and selectivity are key issues in current chemical modification of proteins. The Michael addition‐like thiol–ene reaction is a useful tool that can be used to tag proteins with high selectivity for the solvent‐exposed thiol groups of proteins. To obtain insight into the bioconjugation of proteins with this method, a kinetic analysis was performed. New vinyl‐substituted pyridine derivatives were designed and synthesized. The reactivity of these vinyl tags with L ‐cysteine was evaluated by UV absorption and high‐resolution NMR spectroscopy. The results show that protonation of pyridine plays a key role in the overall reaction rates. The kinetic parameters were assessed in protein modification. The different reactivities of these vinyl tags with solvent‐exposed cysteine is valuable information in the selective labeling of proteins with multiple functional groups. 相似文献
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Chen Tan Michelle C. Lee Mohammad Arshadi Morteza Azizi Alireza Abbaspourrad 《Angewandte Chemie (International ed. in English)》2020,59(24):9506-9513
Processing metal–organic frameworks (MOFs) into hierarchical macroscopic materials can greatly extend their practical applications. However, current strategies suffer from severe aggregation of MOFs and limited tuning of the hierarchical porous network. Now, a strategy is presented that can simultaneously tune the MOF loading, composition, spatial distribution, and confinement within various bio‐originated macroscopic supports, as well as control the accessibility, robustness, and formability of the support itself. This method enables the good dispersion of individual MOF nanoparticles on a spiderweb‐like network within each macrovoid even at high loadings (up to 86 wt %), ensuring the foam pores are highly accessible for excellent adsorption and catalytic capacity. Additionally, this approach allows the direct pre‐incorporation of other functional components into the framework. This strategy provides precise control over the properties of both the hierarchical support and MOF. 相似文献
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Tetsuya Doi Takumi Sakakibara Dr. Hiromu Kashida Dr. Yasuyuki Araki Prof. Dr. Takehiko Wada Prof. Dr. Hiroyuki Asanuma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):15974-15980
We report on the characterization of a novel hetero‐selective DNA‐like duplex of pyrene and anthraquinone pseudo base pairs. The pyrene/anthraquinone pairs showed excellent selectivity in hetero‐recognition and even trimers were found to form a hetero‐duplex. Pyrene and anthraquinone moieties were tethered on acyclic D ‐threoninol linkers and linked to adjacent residues by using standard phosphoramidite chemistry. When pyrene and anthraquinone were incorporated at pairing positions in complementary strands of natural DNA oligonucleotides, the duplex was stabilized significantly. Moreover, a pyrene hexamer and an anthraquinone hexamer formed a stable artificial hetero‐duplex without the assistance of natural base pairs. The pyrene/anthraquinone pair was so stable that even trimers formed a hetero‐duplex under conditions in which natural DNA strands of three residues do not. 相似文献
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Tomoyuki Shibuguchi Hisashi Mihara Akiyoshi Kuramochi Takashi Ohshima Dr. Masakatsu Shibasaki Prof. Dr. 《化学:亚洲杂志》2007,2(6):794-801
Catalytic asymmetric Michael and Mannich‐type reactions of glycine Schiff bases with chiral two‐center organocatalysts, tartrate‐derived diammonium salts (TaDiASs), are described. On the basis of conformational studies, optimized TaDiASs with a 2,6‐disubstituted cyclohexane spiroacetal were newly designed. These TaDiASs catalyzed the asymmetric Michael and Mannich‐type reactions of glycine Schiff bases with higher enantioselectivity than previous catalysts. In the Mannich‐type reaction, aromatic N‐Boc‐protected imines (Boc=tert‐butoxycarbonyl) as well as enolizable alkyl imines were applicable. As a synthetic application of the catalytic asymmetric Mannich‐type reaction with the optimized TaDiASs, we developed a catalytic asymmetric total synthesis of (+)‐nemonapride, which is an antipsychotic agent. 相似文献
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Fruity electrodes : A simple bottom‐up self‐assembly method was used to fabricate rambutan‐like tin–carbon (Sn@C) nanoarchitecture (see scheme, green Sn) to improve the reversible storage of lithium in tin. The mechanism of the growth of the pear‐like hairs is explored.
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Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion‐Like Temperatures 下载免费PDF全文
Dr. Dorian S. N. Parker Prof. Dr. Ralf. I. Kaiser Dr. Biswajit Bandyopadhyay Dr. Oleg Kostko Dr. Tyler P. Troy Dr. Musahid Ahmed 《Angewandte Chemie (International ed. in English)》2015,54(18):5421-5424
The hydrogen abstraction/acetylene addition (HACA) mechanism has long been viewed as a key route to aromatic ring growth of polycyclic aromatic hydrocarbons (PAHs) in combustion systems. However, doubt has been drawn on the ubiquity of the mechanism by recent electronic structure calculations which predict that the HACA mechanism starting from the naphthyl radical preferentially forms acenaphthylene, thereby blocking cyclization to a third six‐membered ring. Here, by probing the products formed in the reaction of 1‐ and 2‐naphthyl radicals in excess acetylene under combustion‐like conditions with the help of photoionization mass spectrometry, we provide experimental evidence that this reaction produces 1‐ and 2‐ethynylnaphthalenes (C12H8), acenaphthylene (C12H8) and diethynylnaphthalenes (C14H8). Importantly, neither phenanthrene nor anthracene (C14H10) was found, which indicates that the HACA mechanism does not lead to cyclization of the third aromatic ring as expected but rather undergoes ethynyl substitution reactions instead. 相似文献
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Andreas Wolfgang Kyri Dr. Vitaly Nesterov Dr. Gregor Schnakenburg Prof. Dr. Rainer Streubel 《Angewandte Chemie (International ed. in English)》2014,53(40):10809-10812
While PV 1,2‐oxaphosphetanes are well known from the Wittig reaction, their PIII analogues are still unexplored. Herein, the synthesis and reactions of the first 1,2‐oxaphosphetane complexes are presented, which were achieved by reaction of the phosphinidenoid complex [Li(12‐crown‐4)(solv)][(OC)5W{(Me3Si)2HCPCl}] with different epoxides. The title compounds appeared to be stable in toluene up to 100 °C, before unselective decomposition started. Acid‐induced ring expansion with benzonitrile resulted in selective formation of the first complex bearing a 1,3,4‐oxazaphosphacyclohex‐2‐ene ligand. 相似文献
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Highly Stereoselective Synthesis of Natural‐Product‐Like Hybrids by an Organocatalytic/Multicomponent Reaction Sequence 下载免费PDF全文
M. Sc. Radell Echemendía M. Sc. Alexander F. de La Torre M. Sc. Julia L. Monteiro M. Sc. Michel Pila Prof. Dr. Arlene G. Corrêa Prof. Dr. Bernhard Westermann Prof. Dr. Daniel G. Rivera Prof. Dr. Márcio W. Paixão 《Angewandte Chemie (International ed. in English)》2015,54(26):7621-7625
In an endeavor to provide an efficient route to natural product hybrids, described herein is an efficient, highly stereoselective, one‐pot process comprising an organocatalytic conjugate addition of 1,3‐dicarbonyls to α,β‐unsaturated aldehydes followed by an intramolecular isocyanide‐based multicomponent reaction. This approach enables the rapid assembly of complex natural product hybrids including up to four different molecular fragments, such as hydroquinolinone, chromene, piperidine, peptide, lipid, and glycoside moieties. The strategy combines the stereocontrol of organocatalysis with the diversity‐generating character of multicomponent reactions, thus leading to structurally unique peptidomimetics integrating heterocyclic, lipidic, and sugar moieties. 相似文献