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781.
Mustafa Saçmacı Çiler Arslaner Ertan Şahin 《Phosphorus, sulfur, and silicon and the related elements》2017,192(10):1134-1139
A series of thidiazole derivatives (4, 7) from pyrazole-3-carboxylic acid chloride (2) and pyrazole-3,4-dicarboxylic acid chloride derivatives (6) were synthesized and characterized. The structures of the new compounds were confirmed byelemental analysis, NMR (1H and 13C) and IR spectra. The molecular and crystal structure of 4-benzoyl-N-[5-(methylthio)-1,3,4-thiadiazol-2-yl]-1,5-di-phenyl-1H-pyrazole-3-carboxamide(4d)was determined by single crystal X-ray diffraction method. 相似文献
782.
You‐Min Ying Xiao‐Sa Liu Cui‐Ping Tong Jian‐Wei Wang Zha‐Jun Zhan Wei‐Guang Shan 《Helvetica chimica acta》2014,97(10):1433-1439
Three new lycopodium alkaloids, huperserramines A–C ( 1 – 3 , resp.), along with 15 known ones, lycopodine‐6α,11α‐diol ( 4 ), lycoposerramine H ( 5 ), lycoposerramine I ( 6 ), lycopodine‐6α‐ol ( 7 ), lycoposerramine M ( 8 ), diphaladine A ( 9 ), lycoposerramine K ( 10 ), lycoposerramine W ( 11 ), huperzine M ( 12 ), luciduline ( 13 ), phlegmariuine N ( 14 ), huperzine A ( 15 ), huperzine B ( 16 ), lycodine ( 17 ), and lycoposerramine R ( 18 ), were isolated from the whole plant of Huperzia serrata. Their structures were established by spectroscopic methods, including 2D‐NMR and MS analyses. All the isolates were evaluated for their inhibitory effects on acetylcholinesterase (AChE) and α‐glucosidase. As a result, lycopodine‐6α,11α‐diol ( 4 ) exhibited more potent α‐glucosidase inhibitory activity (IC50 148±5.5 μM ) than the positive control acarbose (IC50 376.3±2.7 μM ). 相似文献
783.
[1,3]-Dipolar cycloadditions of N-aryl sydnones to benzothiophene 1,1-dioxide, 1-cyclopropylprop-2-yn-1-ol and 1-(prop-2-ynyl)indole gave fused pyrazole derivatives when carried out in refluxing toluene. While the first two dipolarophiles gave single regioisomers, this indolic derivative gave mixtures, the ratios of which appeared to be controlled by the phenyl substituents. Their structures were identified in the usual manner, supported by single crystal X-ray diffraction measurements. 相似文献
784.
A simple and useful tandem addition–cyclization reaction of primary amines on a prepared α-functionalized propylvinyl ketone 3 in methanol at reflux is a promising route for the synthesis of a new family of 1-alkyl-4-propionylpyrrolidin-2-ones 4.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
785.
Coordination Chemistry of [Co(acac)2] with N‐Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co‐O4‐N Species
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Jongwoo Han Young Jin Sa Yeonjun Shim Min Choi Prof. Dr. Noejung Park Prof. Dr. Sang Hoon Joo Prof. Dr. Sungjin Park 《Angewandte Chemie (International ed. in English)》2015,54(43):12622-12626
Hybridization of organometallic complexes with graphene‐based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the reaction of an organometallic complex, [CoII(acac)2] (acac=acetylacetonate), with N‐doped graphene‐based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt‐containing species is coordinated to heterocyclic groups in N‐doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co‐O4‐N structure. 相似文献
786.
Catalytic Cyclization of o‐Alkynyl Phenethylamines via Osmacyclopropene Intermediates: Direct Access to Dopaminergic 3‐Benzazepines
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Andrea Álvarez‐Pérez Dr. Carlos González‐Rodríguez Dr. Cristina García‐Yebra Dr. Jesús A. Varela Dr. Enrique Oñate Prof. Miguel A. Esteruelas Prof. Carlos Saá 《Angewandte Chemie (International ed. in English)》2015,54(45):13357-13361
A novel osmium‐catalyzed cyclization of o‐alkynyl phenethylamines to give 3‐benzazepines is reported. The procedure allows the straightforward preparation of a broad range of dopaminergic 3‐benzazepine derivatives. Mechanistic investigations revealed that the process takes place via osmacyclopropene intermediates, which were isolated and characterized by X‐ray crystallography. 相似文献
787.
Alissa Wiengarten Julian A. Lloyd Dr. Knud Seufert Dr. Joachim Reichert Dr. Willi Auwärter Runyuan Han Dr. David A. Duncan Dr. Francesco Allegretti Dr. Sybille Fischer Dr. Seung Cheol Oh Dr. Özge Sağlam Li Jiang Dr. Saranyan Vijayaraghavan Dr. David Écija Dr. Anthoula C. Papageorgiou Prof. Dr. Johannes V. Barth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(35):12285-12290
Selectivity in chemical reactions is a major objective in industrial processes to minimize spurious byproducts and to save scarce resources. In homogeneous catalysis the most important factor which determines selectivity is structural symmetry. However, a transfer of the symmetry concept to heterogeneous catalysis still requires a detailed comprehension of the underlying processes. Here, we investigate a ring‐closing reaction in surface‐confined meso‐substituted porphyrin molecules by scanning tunneling microscopy, temperature‐programmed desorption, and computational modeling. The identification of reaction intermediates enables us to analyze the reaction pathway and to conclude that the symmetry of the porphyrin core is of pivotal importance regarding product yields. 相似文献
788.
Frédéric Jamin Moulay Saı̈d El Youssoufi Christian Saix 《Comptes Rendus Mecanique》2004,332(2):153-159
A study of temperature influence on the yield surface for one unsaturated soil at constant suction is presented. Mechanical consolidation tests are realized at different temperatures on clayey silty sand. A specific triaxial apparatus for unsaturated soils with temperatures included between 30 °C and 60 °C is used. Experimental results show without ambiguity a thermo-extensive nature of the yield surface. The physical interpretation proposed calls for microscopic considerations on the menisci capillary evolution according to temperature and suction. To cite this article: F. Jamin et al., C. R. Mecanique 332 (2004). 相似文献
789.
Modeling the Dynamics and Kinematics of a Telescopic Rotary Crane by the Bond Graph Method: Part II 总被引:1,自引:0,他引:1
Simulation of a rotary telescopic crane for which a detailed nonlinearbond graph model has been established in Part I of this study, isrealized utilizing experimental actual system for geometrical anddynamical parameters. With the intention of comparing the real system andthe model and of verifying the sufficiency of the model accuracy,various scenarios are defined corresponding to different loading andoperating conditions. Of the scenarios defined, impulse response, timeresponse and static response are used to experimentally gather such system parameters and variables as damping coefficient, cylinderdisplacements, and stiffness of the telescopic boom, respectively.Following, the simulation for two dissimilar scenarios which are staticresponse and impulse response is undergone and results are presented. 相似文献
790.
In ([11]), we have studied quadratic Leibniz algebras that are Leibniz algebras endowed with symmetric, nondegenerate, and associative (or invariant) bilinear forms. The nonanticommutativity of the Leibniz product gives rise to other types of invariance for a bilinear form defined on a Leibniz algebra: the left invariance, the right invariance. In this article, we study the structure of Leibniz algebras endowed with nondegenerate, symmetric, and left (resp. right) invariant bilinear forms. In particular, the existence of such a bilinear form on a Leibniz algebra 𝔏 gives rise to a new algebra structure ☆ on the underlying vector space 𝔏. In this article, we study this new algebra, and we give information on the structure of this type of algebras by using some extensions introduced in [11]. In particular, we improve the results obtained in [22]. 相似文献