钯催化Suzuki偶联反应合成2-(3'-噻吩基)噻唑

以3-噻吩硼酸和2-溴噻唑为原料,以Pd(PPh3)4为催化剂,通过Suzuki偶联反应合成了2-(3'-噻吩基)噻唑,考察了不同的碱,不同的溶剂,不同原料比例和不同催化剂比例对该Suzuki偶联反应产率的影响.结果显示:目标产物收率在溶剂为乙醇,K2CO3为碱,原料比例为1.5:1的时候最高,且反应时间较短.     

钯催化Suzuki偶联反应合成2-(3'-噻吩基)噻唑

以3-噻吩硼酸和2-溴噻唑为原料,以Pd(PPh3)4为催化剂,通过Suzuki偶联反应合成了2-(3'-噻吩基)噻唑,考察了不同的碱,不同的溶剂,不同原料比例和不同催化剂比例对该Suzuki偶联反应产率的影响.结果显示:目标产物收率在溶剂为乙醇,K2CO3为碱,原料比例为1.5:1的时候最高,且反应时间较短.     

钯催化芳基重氮盐偶联反应的研究进展

综述了目前国内外关于钯催化的芳基重氮盐参与的直接催化氧化偶联反应的最新研究进展,包括芳基重氮盐的自身偶联、Suzuki偶联、Heck偶联、Hiayama偶联和Sonogashira偶联,从不同的反应类型、催化体系和各自的优缺点方面展开了讨论.     

1-芳基-3-芳甲酰基中氮茚的合成

合成了九个1-芳基中氮茚衍生物。首先由取代苯乙酮,碘,乙酸和吡啶四组分一锅煮反应合成中间体1-碘代中氮茚,然后在钯催化剂作用下,使用制得的的1-碘代中氮茚和芳基硼酸的Suzuki偶联反应合成得到目标化合物,所合成化合物结构通过红外,核磁及质谱进行了表征。     

负载钯及非钯型Suzuki偶联反应催化剂体系的研究进展

Suzuki偶联反应是现代有机合成化学中构筑碳碳键的最有效方法之一。传统的Suzuki反应催化剂主要是Pd(PPh3)4、Pd(OAc)2等均相催化剂。这类催化剂的活性较高,但其价格高、化学稳定性较差、难以与反应液分离和回收再利用等缺点也是不容忽视的。近年来,人们开发了一系列具有不同的钯材料载体(碳材料、高分子材料以及无机材料等)的非均相催化剂体系,以及基于Ni、Cu、Mn等过渡金属的新型催化体系。这些新型的催化剂体系的发展有效地解决了上述均相催化剂的不足。综述了近来Suzuki反应在负载催化剂和非钯催化剂方面的研究进展。     

钯催化Suzuki偶联反应的研究进展

金属Pd催化的Suzuki偶联反应是碳-碳偶联反应中重要的反应之一。综述了近年来Pd催化Suzuki偶联反应的研究进展,其中包括Suzuki反应机理、配体种类及其在有机合成中的应用。介绍了含N、P配体的钯催化剂和碳纳米管、磁性材料、多孔材料、水滑石、金属氧化物、高分子材料等负载的无配体钯催化剂的研究进展。     

醋酸钯催化直接芳基化合成2-芳基吲哚类化合物

为探究操作简便、绿色经济、底物适用性强的合成2-苯基吲哚类化合物的新方法,对反应溶剂、催化剂种类及用量、氧化剂种类和反应温度等反应条件进行筛选,选取最佳反应条件对取代吲哚及取代苯硼酸进行底物适用性实验,并进行结构表征。实验得到以物质的量分数为10%的Pd(OAc)₂为催化剂,物质的量分数为20%的Cu(OAc)₂为氧化剂,冰乙酸为溶剂,室温反应8 h为最佳反应条件,共合成了23个2-芳基吲哚类化合物,产率高达87%。本实验开发了一步合成2-芳基吲哚类化合物的方法,该方法对不同取代的吲哚和苯硼酸均具有较好的适用性,与已报道的方法相比,本方法具有底物适用性强、产率高、操作简便、经济环保等优点,为2-芳基吲哚类化合物的制备提供了更加高效的路径。     

金属钯催化的偶联反应的研究总结

偶联反应是一类构建碳-碳键的重要化学反应,其应用十分广泛。本文对钯催化的Suzuki、Heck、Sonogashira、Kumada、Negishi、Stille、Hiyama等偶联反应的研究进行了综述,分析了上述反应的优缺点及研究成果,并对该类反应的发展前景进行了归纳总结。     

超声波辐射合成2-氨基噻唑衍生物

在超声波辐射下,α-溴代芳基酮和硫脲反应合成了8种2-氨基噻唑衍生物.该反应时间短、产率高、环境友好、后处理方便.     

一种铁催化的四氟硼酸芳基重氮盐合成联苯类化合物方法的研究

一种简单高效的在温和条件下用四氟硼酸芳基重氮盐和铁盐在四氯化碳溶剂中进行的自身偶联反应,可以较高的产率得到各种自身偶联的联苯类化合物。     

负载钯催化Suzuki偶联反应的研究进展

过渡金属钯催化C-C偶联反应在有机合成中具有重要地位,负载型钯催化剂具有分离简便、可重复使用等优点,引起了人们的关注。综述了不同载体催化剂催化Suzuki偶联反应的研究进展。     

无配体负载钯催化Suzuki偶联反应的研究进展

金属钯催化的Suzuki偶联反应是碳一碳偶联反应中的最重要的反应之一。传统的均相催化体系具有很多的不足,如产物与催化剂不易分离、原料价格昂贵、催化剂不能重复使用等,而使用无配体负载钯的催化剂可有效地解决上述问题。综述了近些年来无配体材料负载钯催化Suzuki偶联反应的研究进展,载体包括碳材料、多孔分子筛、水滑石、高分子材料、金属氧化物、硅藻土、纤维素、磷灰石和氟硅胶等。     

Electron‐Poor,Fluoro‐Containing Arylboronic Acids as Efficient Coupling Partners for Bis(1,5‐cyclooctadiene)nickel(0)/Tricyclohexylphosphine‐Catalyzed Cross‐Coupling Reactions of Aryl Arenesulfonates

The use of electron‐poor, fluoro‐containing arylboronic acids as general coupling partners for nickel(0)/tricyclohexylphosphine‐catalyzed cross‐coupling of aryl arenesulfonates is described. Electron‐poor fluoro‐containing arylboronic acids were found to react faster than electron‐rich/neutral arylboronic acids, with (4‐methoxyphenyl)(4‐methylbenzenesulfonato‐κO)bis(tricyclohexylphosphine)nickel. Bis(1,5‐cyclooctadiene)nickel(0)/tricyclohexylphosphine, (4‐methoxyphenyl)(4‐methylbenzenesulfonato‐κO)bis(tricyclohexylphosphine)nickel and bis(tricyclohexylphosphine)nickel(II) bromide were all found to be efficient catalysts/catalyst precursors.

     

Palladium‐Catalyzed Cyclization Reactions of Acetylene‐Containing Amino Acids

Enantiomerically pure acetylene‐containing α‐amino acids were used as versatile starting materials for the synthesis of a variety of heterocycles via Pd‐mediated cyclization reactions. Depending on the protecting group strategy, both the carboxylate and the amine function of the amino acids could participate in the cyclizations, thus giving rise to oxygen heterocycles (α‐aminolactones) and nitrogen heterocycles (cyclic α‐amino acid derivatives), respectively. Beside the straightforward cyclization, cyclization/cross‐coupling reactions were also successfully carried out to provide the corresponding substituted cyclic amino acid derivatives.     

Efficient Modular Synthesis of Isomeric Mono‐ and Bispyridyl[2.2]paracyclophanes by Palladium‐Catalyzed Cross‐ Coupling Reactions

Pyridyl‐substituted [2.2]paracyclophanes build a multifunctional structural motif that is useful in material chemistry, catalysis and for luminescent structures. Nonetheless, there is still a lack of general methods for the synthesis of these structures tolerating easily accessible bromides as well as different isomeric pyridyl groups. Hence the coupling of functionalized [2.2]paracyclophanes with various substituted and functionalized pyridyl derivatives was achieved using Stille, Suzuki and Kumada coupling conditions. Hereby the Stille coupling of a [2.2]paracyclophane is presented as a versatile reaction for the formation of heteromeric [2.2]paracyclophane‐containing biaryl structures.

     

Inhibition of Steel Corrosion in Nitric Acid by Sulfur Containing Compounds

The inhibitive mechanism, thermodynamics, and adsorptive properties of thiobarbituric acid (TBA) and thiourea (TU) on the corrosion of mild steel in 0.5 M HNO₃ solution have been investigated using potentiodynamic, electrochemical impedance spectroscopy techniques, and quantum chemical calculations. Both inhibitors showed good inhibition efficiency in nitric acid solution. TU was the most effective inhibitor and its inhibition efficiency increases with increasing concentration to attain 99% at 6 × 10^?3 mol · L^?1 at 30°C. Theoretical fitting of different isotherms, Langmuir, Flory–Huggins, Temkin, and the kinetic-thermodynamic models were tested to clarify the nature of inhibitors adsorption on mild steel surface. The obtained experimental data fitted all the applied adsorption isotherms except Langmuir. The thermodynamic activation parameters were determined to provide evidence of the inhibitory effect of TBA and TU. To determine the surface charge at the steel surface in nitric acid solution the potential of zero charge was measured using AC measurements at different potentials. Quantum chemical parameters were calculated and explained. The data clarified that the inhibition of steel in nitric acid by TU or TBA takes place through physicochemical adsorption mechanism.     

A Synthetic Approach to Star‐Like Polymers of Styrene and Butyl Acrylate by Linking Reactions using Functionalized Methacrylates

Summary: Coupling reactions between terminal functionalized polymer chains were chosen for the synthesis of star‐like polymers consisting of polystyrene and polystyrene‐block‐poly[styrene‐co‐(butyl acrylate)] arms. For the preparation of terminal functionalized polymer chains a side reaction of the 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) mediated free radical polymerization of methacrylates could be used successfully to convert TEMPO terminated polymers into end functionalized polymers. The number of functionalized monomer units attached to the polymer chain is directly related to the TEMPO concentration during this reaction. Different polystyrenes and polystyrene‐block‐poly[styrene‐co‐(butyl acrylate)] block copolymers were functionalized with a variable number of epoxide and alcohol groups at the chain end. For the determination of the optimal reaction parameters for the coupling reactions between these polymer chains, epoxy functionalized polystyrenes were converted with hydroxy functionalized polystyrenes under basic and acidic conditions. By activation with sodium hydride or boron trifluoride star‐like polymers were synthesized under mild conditions. The transfer of the reaction conditions to coupling reactions between end functionalized polystyrene‐block‐poly[styrene‐co‐(butyl acrylate)] copolymers showed that star‐like polymers with more than 12 arms were formed using boron trifluoride as activating agent.

     

Pd催化下Suzuki偶联反应合成5’-硝基-[2,2’-联噻吩]-5-甲醛

以2-溴-5-硝基噻吩(BNT)和5-甲酰基-2-噻吩硼酸(FTBA)为原料,通过Suzuki偶联反应合成了5’-硝基-[2,2’-联噻吩]-5-甲醛,考察了碱、溶剂、催化剂及加料顺序对该Suzuki偶联反应的影响。结果显示:优化条件为以1,2-二甲氧基乙烷(DME)为溶剂,氟化钠为碱,Pd/C为催化剂,一锅加料。     

One‐Pot Synthesis of Biaryl Lactones by Sonogashira Cross‐Coupling Reactions of 4‐Chloro‐3‐formylcoumarin and Subsequent Domino [5+1] Cyclization/Deacetylation Reactions with 1,3‐Dicarbonyl Compounds

Biaryl lactones were prepared by a new palladium(0) and base‐catalyzed one‐pot reaction of 4‐chloro‐3‐formylcoumarin with alkynes and 1,3‐dicarbonyl compounds.