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排序方式: 共有294条查询结果,搜索用时 15 毫秒
1.
Visible light-induced hydroxyalkylation of 2H-benzothiazoles with alcohols via selectfluor oxidation
A visible-light induced metal-free approach was described for the hydroxyalkylation of 2H-benzothiazoles with alcohols by using selectfluor as the oxidant. A variety of 2H-benzothiazoles and alcohols could be tolerated, providing a mild and simple method for the synthesis of C2-hydroxyalkylated 2H-benzothiazoles in moderate to good yields. Besides, ethers were also compatible in this reaction, leading to corresponding C2 ether-substituted 2H-benzothiazoles with high regioselectivity. 相似文献
2.
Nonlinear Dynamics - In this paper, we employ a novel method for solving the problem of the global exponential stability of quaternion-valued recurrent neural networks (QVNNs) with time-varying... 相似文献
3.
Reported herein is the FeCl3-promoted intermolecular sulfoesterification of o-(1-alkynyl)benzoates with disulfides, which provides a convenient and efficient method for synthesis of 4-sulfenylisocoumarins. Various functional groups such as methoxy, halides, ester, cyano and silicon groups in the substrates are tolerated, and heterocycle-fused chalcogenylpyrones are also successfully achieved directly from the corresponding heterocyclic precursors under the same reaction conditions. In addition, starting from diynylbenzoate, this reaction sequence can be combined with a bicyclization step leading to the tetracyclic (E)-3-(2-phenyl-3-phenylchalcogenylinden-1-ylidene)isobenzofuranone frameworks with high regiospecificity and exclusive trans stereoselectivity. 相似文献
4.
Yuhui Kou Derong Cao Hongqi Tao Lingyun Wang Jianquan Liang Zhizhao Chen Herbert Meier 《Journal of inclusion phenomena and macrocyclic chemistry》2013,77(1-4):279-289
A detailed study of the reaction conditions revealed that a quantitative cyclocondensation of 1,4-dialkoxy-2,5-bis(alkoxymethyl)-benzenes to pillar[n]arenes can be achieved by catalysis of p-toluenesulfonic acid in CH2Cl2. Major product of this new reaction is in each case a cyclopentamer (n = 5), but small amounts of the pillar[n]arenes with n = 6, 7 and 10 can be obtained as well. Different alkoxy groups in 1- and 4-position lead to regioisomers. All cyclooligomers exist in pillar structures as pair of enantiomers, which show a racemisation at room temperature, which is fast in terms of the NMR time scale. The racemisation process occurs by rotation of the 1,4-phenylene segments in the macrocyclic rings. Pillar[n]arenes exhibit novel host–guest behavior. 相似文献
5.
In this paper, an SIR epidemic model with vaccination for both the newborns and susceptibles is investigated, where it is assumed that the vaccinated individuals have the temporary immunity. The basic reproduction number determining the extinction or persistence of the infection is found. By constructing a Lyapunov function, it is proved that the disease free equilibrium is globally stable when the basic reproduction number is less than or equal to one, and that the endemic equilibrium is globally stable wh... 相似文献
6.
We prove that the octonionic polynomials V ■k l 1 ··· l k are independent of the associative orders ■k . This improves the octonionic Taylor type theorem. 相似文献
7.
Under given performance constraint, this paper studies the stabilization problem of general dynamical network subject to noise disturbance. The newly presented dynamical network model includes both intrinsic disturbance of single node and communication noise over the network connections, which appear typically in a network environment. Single controller is pinned into one of the nodes for the exponential stabilization of dynamical network, and the prescribed performance constraint is satisfied. The reason why only one controller is valid for stabilization of dynamical network is the full utilization of network’s local connections. One important feature of this paper is the introduction of the performance constraint concept into the stabilization of complex dynamical network with intrinsic and communication noises. The derived criteria are expressed in terms of linear matrix inequalities (LMIs), which are easy to be verified by resorting to recently developed algorithm. Numerical example is utilized to illustrate the effectiveness of the proposed results. 相似文献
8.
9.
Back Cover: Silver‐Catalyzed Cross‐Coupling of Propargylic Alcohols with Isocyanides: An Atom‐Economical Synthesis of 2,3‐Allenamides (Chem. Eur. J. 8/2014) 下载免费PDF全文
10.
Silver‐Catalyzed Cross‐Coupling of Propargylic Alcohols with Isocyanides: An Atom‐Economical Synthesis of 2,3‐Allenamides 下载免费PDF全文
Jianquan Liu Zhenhua Liu Nannan Wu Dr. Peiqiu Liao Prof. Xihe Bi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2154-2158
Cross‐coupling reactions between propargylic alcohols and isocyanides, by means of silver catalysis, have been described. This new reaction is both atom and step efficient and is applicable to a broad scope of substrates, allowing the synthesis of a range of synthetically valuable 2,3‐allenamides in moderate to excellent yields. 相似文献