- Superhydrophobic nickel/carbon core-shell nanocomposites for the hydrogen transfer reactions of nitrobenzene and N-heterocycles
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In this work, catalytic hydrogen transfer as an effective, green, convenient and economical strategy is for the first time used to synthesize anilines and N-heterocyclic aromatic compounds from nitrobenzene and N-heterocycles in one step. Nevertheless, how to effectively reduce the possible effects of water on the catalyst by removal of the by-product water, and to further introduce water as the solvent based on green chemistry are still challenges. Since the structures and properties of carbon nanocomposites are easily modified by controllable construction, a one step pyrolysis process is used for controllable construction of micro/nano hierarchical carbon nanocomposites with core-shell structures and magnetic separation performance. Using various characterization methods and model reactions the relationship between the structure of Ni?NCFs (nickel-nitrogen-doped carbon frameworks) and catalytic performance was investigated, and the results show that there is a positive correlation between the catalytic performance and hydrophobicity of catalysts. Besides, the possible catalytically active sites, which are formed by the interaction of pyridinic N and graphitic N in the structure of nitrogen-doped graphene with the surfaces of Ni nanoparticles, should be pivotal to achieving the relatively high catalytic performance of materials. Due to its unique structure, the obtained Ni?NCF-700 catalyst with superhydrophobicity shows extraordinary performances toward the hydrogen transfer reaction of nitrobenzene and N-heterocycles in the aqueous state; meanwhile, it was also found that Ni?NCF-700 still retained its excellent catalytic activity and structural integrity after three cycles. Compared with traditional catalytic systems, our catalytic systems offer a highly effective, green and economical alternative for nitrobenzene and N-heterocycle transformation, and may open up a new avenue for simple construction of structure and activity defined carbon nanocomposite heterogeneous catalysts with superhydrophobicity.
- Duan, Zhiying,Liu, Fangfang,Pang, Shaofeng,Su, Qiong,Wang, Yanbin,Xie, Xin,Zhang, Ping,Zhang, Yujing,Zhou, Feng
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p. 1996 - 2010
(2020/04/07)
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- Chemokine receptor binding heterocyclic compounds
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This invention relates to a novel class of heterocyclic compounds that bind chemokine receptors, inhibiting the binding of their natural ligands thereby. These compounds result in protective effects against infection by HIV through binding to chemokine receptors, including CXCR4 and CCR5, thus inhibiting the subsequent binding by these chemokines. The present invention provides a compound of Formula I wherein, W is a nitrogen atom and Y is absent or, W is a carbon atom and Y═H; R1to R7may be the same or different and are independently selected from hydrogen or straight, branched or cyclic C1-6alkyl; R8is a substituted heterocyclic group or a substituted aromatic group Ar is an aromatic or heteroaromatic ring each optionally substituted at single or multiple, non-linking positions with electron-donating or withdrawing groups; n and n′ are independently, 0-2; X is a group of the formula: Wherein, Ring A is an optionally substituted, saturated or unsaturated 5 or 6-membered ring, and P is an optionally substituted carbon atom, an optionally substituted nitrogen atom, sulfur or oxygen atom. Ring B is an optionally substituted 5 to 7-membered ring. Ring A and Ring B in the above formula can be connected to the group W from any position via the group V, wherein V is a chemical bond, a (CH2)n″group (where n″=0-2) or a C═O group. Z is, (1) a hydrogen atom, (2) an optionally substituted C1-6alkyl group, (3) a C0-6alkyl group substituted with an optionally substituted aromatic or heterocyclic group, (4) an optionally substituted C0-6alkylamino or C3-7cycloalkylamino group, (5) an optionally substituted carbonyl group or sulfonyl. These compounds further include any pharmaceutically acceptable acid addition salts and metal complexes thereof and any stereoisomeric forms and mixtures of stereoisomeric forms thereof.
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Page column 41-42
(2008/06/13)
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- Sulfuric acid on silica-gel: An inexpensive catalyst for aromatic nitration
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Solid acidic catalysts made of sulfuric acid supported on silica-gel and their application to the nitration of aromatics with nitric acid and isopropyl nitrate are described. Substrates with very different levels of activation were investigated. Methods to overcome the poisoning produced by water and to tune the catalysts activity according to the reactivity of the substrate are outlined.
- Riego, Juan M.,Sedin, Zeno,Zaldivar, Jose M.,Marziano, Nunziata C.,Tortato, Claudio
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p. 513 - 516
(2007/10/02)
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- NUCLEOPHILIC HETEROAROMATIC SUBSTITUTIONS. XXXIX. THE REACTION OF α- AND γ-- AND α- AND γ--7-NITROQUINOLINE WITH PIPERIDINE IN BENZONITRILE: BASE CATALYSIS AND O vs S REACTIVITY
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The reactivity of the title compounds with piperidine has been examined.Product analysis showed that substitution is accompanied by other processes, the extent of which depends on the reactivity of the substrates towards nucleophilic substitution and is greatest in the case of the γ-arylthio derivative, which does not undergo substitution at all.Accordingly, a kinetic analysis of the reaction could be performed only for the two aryloxy and the α-arylthio derivatives.Second-order rate coefficients for the reactions of the α-substituted quinolines were found to be independent of amine concentration and the α-aryloxy derivative was found to be only ca 4 times as reactive as the α-arylthio compound.In contrast, the reaction of the γ-aryloxy derivative followed third-order kinetics and turned out to be base-catalysed because it was accelerated by added quinuclidine.The reaction mechanisms are discussed in the light of these observations and other, previously reported, facts.
- Cidda, Claudio,Sleiter, Giancarlo
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p. 155 - 162
(2007/10/02)
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