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排序方式: 共有240条查询结果,搜索用时 281 毫秒
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Rana Chatterjee Satyajit Samanta Anindita Mukherjee Sougata Santra Grigory V. Zyryanov Adinath Majee 《Tetrahedron letters》2019,60(3):276-283
We have observed that the allylic zinc halide under identical reaction conditions acts in different modes for different electrophiles. For Ts-aziridines the halide part of the allylic halide has been introduced as a nucleophile and for the carbonyl compounds the simple allylation reaction occurs. To the best of our knowledge this is the first report where the allylic zinc halide is the source of halide acting as nucleophile. The main advantages of the present procedure are easy to handle, no need of inert atmosphere, mild reaction conditions, and applicability to a wide variety of substrates for aziridines and carbonyl compounds. 相似文献
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Madhu Kumar Reddy Kandula Mohan Gundluru Bakthavatchala Reddy Nemallapudi Sravya Gundala Peddanna Kotha Grigory V. Zyryanov Sridevi Chadive Suresh Reddy Cirandur 《Journal of heterocyclic chemistry》2021,58(1):172-181
A novel series of piperazine-1,2,3-triazole bearing dimethyl(((2-(4-((1H-1,2,3-triazole-4-yl)methyl)piperazin-1-yl)ethylamino)(2-hydroxyaryl)methyl)phosphonate derivatives have been prepared via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) (Click Reaction) and Schiff base reactions. The synthesized compounds were confirmed by spectral characterization (1H, 13C and 31P NMR, and mass). The title compounds were evaluated for in vitro alpha glucosidase enzyme inhibition and in vitro antioxidant activity using DPPH and H2O2 methods. 相似文献
4.
Denis D. Borisov Grigory R. Chermashentsev Roman A. Novikov Yury V. Tomilov 《Tetrahedron letters》2019,60(10):746-750
New “four-component” self-assembly of polyaromatic thiophene structures based on styrylmalonates and 5-phenylthiophene-2-carbaldehyde has been developed. This process is promoted by GaCl3 and involves two [2?+?3]-annulation steps on the CHO-groups and para-substitution into one Ph-ring. The main feature of discovered process is a high diastereoselectivity with a significant increase in molecular complexity. The resulting polyaromatic structures containing two thiophene moieties in each structure have intense color and strong absorption in a near UV spectral region with absorption maxima in the range of 257–360?nm. 相似文献
5.
Bakthavatchala Reddy Nemallapudi Grigory V. Zyryanov Balakrishna Avula Mallikarjuna Reddy Guda Sravya Gundala 《Journal of heterocyclic chemistry》2019,56(12):3324-3332
An effective and suitable meglumine‐catalyzed high‐yielding process was considered and engaged for the synthesis of new bis(indolyl)methanes at ambient temperature under aqueous conditions. The catalytic reaction proceeds very smoothly. Clean reaction, ease of product isolation/purification, easily available reactant and ecofriendly reaction conditions are the notable advantages of the present methodology. All the title compounds were characterized by IR, 1H, 13C NMR, and mass spectra. All the synthesized compounds were tested for antimicrobial activity, and the results indicated that most of the synthesized compounds exhibited excellent activity against the tested microorganisms. In this new series, compound 3l , having nitro substituent on the aromatic ring, showed exceptional potent inhibitory activity against Pseudomonas aeruginosa and Penicillium chrysogenum. 相似文献
6.
New insights into water‐soluble and water‐coordinated copper 15‐metallacrown‐5 gadolinium complexes designed for high‐field magnetic resonance imaging applications 下载免费PDF全文
Marina A. Katkova Galina S. Zabrodina Evgeny V. Baranov Maria S. Muravyeva Evgeny A. Kluev Andrey S. Shavyrin Grigory Yu Zhigulin Sergey Yu Ketkov 《应用有机金属化学》2018,32(7)
The development of contrast agents specifically designed for high‐field magnetic resonance imaging (MRI) is required because the relaxation efficiency of classic Gd(III) contrast agents significantly decreases with increasing magnetic field strengths. With an idea of exploring the unique structure of lanthanide (Ln) 15‐MC‐5 metallacrowns, we developed a series of water‐soluble Gd(III) aqua‐complexes, bearing aminohydroxamate (glycine, α‐alanine, α‐phenylalanine and α‐tyrosine) ligands, with increasing number of water molecules directly coordinated to the Gd(III) ion: Gd(H2O)4[15‐MCCu(II)Glyha‐5](Cl)3 ( 1 (Gd)), Gd(H2O)4[15‐MCCu(II)Alaha‐5](Cl)3 ( 2 (Gd)), Gd(H2O)3[15‐MCCu(II)Phalaha‐5](Cl)3 ( 3 (Gd)) and Gd(H2O)3[15‐MCCu(II)Tyrha‐5](Cl)3 ( 4 (Gd)). In these systems, the Ln(III) central ion is coordinated by five oxygen donor atoms of the ligands and three or four inner‐sphere water molecules. The X‐ray crystal structure of metallacrown Ln(H2O)3,4[15‐MCCu(II)Rha‐5]3+ agrees with density functional theory predictions. The calculations demonstrate that the exchange of coordinated water molecules can proceed easily, resulting in increased relaxivity parameters. The longitudinal relaxivities (r1) of 1 (Gd)– 4 (Gd) in water at ultrahigh magnetic field of 9.4 T were determined to be 11.5, 14.8, 13.9 and 12.2 mM?1 s?1, respectively. The ability to increase the number of Ln(III) inner‐sphere water molecules up to four, the planar metallacrown structure and the rich hydration shell due to strong hydrogen bonds between the [15‐MC‐5] moiety and bulk water molecules provide new opportunities for potential MRI applications. 相似文献
7.
Optimal process control with control constraints is a challenging task related to many real-life problems. In this paper, a single input continuous time constrained linear quadratic regulator problem, is defined and fully solved. The constraints include both bilinear inequality constraints and customary control force bounds. As a first step, the problem is reformulated as an equivalent constrained bilinear biquadratic optimal control problem. Next, Krotov’s method is used to solve it. To this end, a sequence of improving functions suitable to the problem’s new formulation is constructed and the corresponding successive algorithm is derived. The required computational steps are arranged as an algorithm and proof outlines for the convergence and optimality of the solution are given. The efficiency of the suggested method is demonstrated by numerical example. 相似文献
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Vladimir Gritsenko Grigory Kabatiansky Vladimir Lebedev Alexey Maevskiy 《Designs, Codes and Cryptography》2017,82(1-2):293-299
We prove new lower bounds on the rate of codes for noisy multiple access adder channel and discuss its application to the well-known coin weighing problem in the case when some measurements are incorrect. 相似文献
10.
由于抗生素的不当使用和细菌多药耐药的出现, 迫切需要开发新的抗菌剂. 本文制备了具有光热转换性能的正电荷半导体高分子材料及具有协同抗菌活性的半导体聚合物纳米粒子(SP-PPh3 NPs). SP-PPh3 NPs的光热转化效率为43.8%. 带正电荷的SP-PPh3 NPs可以附着在细菌上, 有助于将热量有效传递给细菌. 在热和正电荷的协同作用下, SP-PPh3 NPs对革兰氏阴性大肠杆菌(E. coli)和革兰氏阳性金黄色葡萄球菌(S. aureus)均具有抗菌活性, 其对二者的体外抑菌率分别为99.9%和98.6%. 此外, SP-PPh3 NPs具有良好的生物相容性, 对小鼠的主要器官几乎无副作用. 对细菌感染的小鼠皮肤伤口用SP-PPh3 NPs治疗12 d后, 伤口可以很好地愈合. 相似文献