- Synthesis of Conjugated Main-Chain Ferrocene-Containing Polymers through Melt-State Polymerization
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Two kinds of conjugated main-chain ferrocene (Fc)-containing polymers, PFcT8 and PFcTP8, were successfully prepared through the facile melt-state polymerization (MSP) of corresponding monomers which combine the Fc motif with thiophene or thiophene-methane groups. The simple, low-cost MSP was chosen as the method, while thiophene or thiophene-methane groups served as reactive sites for its feature of easy polymerization by a simple heating process. The prepared metallopolymers were characterized by 1H NMR, FTIR, and photochemical and electrochemical analysis, metal content, and thermal stability. The results show that metallopolymers with a regular backbone and nearly quantitative metal content were obtained. In addition, the metallopolymer PFcTP8 has the smallest optical band gap (absorption edge at 1100 nm) and high thermal stability among reported Fc-containing polymers, which indicates the thiophene-methane-based Fc-containing structure is a good candidate to construct functional polymers through MSP. The low band gap and high thermal stability of prepared conjugated metallopolymers show their potential application in conducting materials with high working temperature.
- Luo, Qi,Zhang, Rui,Zhang, Jing,Xia, Jiangbin
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- Solvent-Free and Liquid-Phase Iodination of Thiophene Derivatives with Potassium Dichloroiodate Monohydrate
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Iodination of a series of benzene and thiophene derivatives by potassium dichloroiodate monohydrate was studied with and without a solvent. The liquid substrates tend to be more reactive in water while the solid substrates afford better yields in dichloromethane or under the solvent-free conditions. The 2-substituted thiophenes show good to excellent yields whereas the yield for 3-substituted and 3,4- or 2,4-disubstituted thiophenes and benzene derivatives are significantly lower. The mechanochemical reaction of 5-carbaldehyde-2,2′-bithiophene shows excellent yields, while 2,2′-bithiophene gives practical yields only in dichloromethane. In the case of thiophene and N -acetyl- p -toluidine, electrophilic iodination is accompanied by a small extent of chlorination.
- Hussain, Anwar,Sarkar, Akash Mamon,Sereda, Grigoriy,Zefirov, Nikolai
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p. 1140 - 1146
(2020/04/01)
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- Negishi's Reagent Versus Rosenthal's Reagent in the Formation of Zirconacyclopentadienes
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Zirconacyclopentadienes are versatile precursors for a large number of heteroles, which are accessible by Zr-element exchange reactions. The vast majority of reports describe their preparation by the use of Negishi′s reagent, which is a species that is fo
- Urrego-Riveros, Sara,Ramirez y Medina, Isabel-Maria,Duvinage, Daniel,Lork, Enno,S?nnichsen, Frank D.,Staubitz, Anne
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supporting information
p. 13318 - 13328
(2019/09/17)
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- Transition-Metal-Free Decarboxylative Iodination: New Routes for Decarboxylative Oxidative Cross-Couplings
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Constructing products of high synthetic value from inexpensive and abundant starting materials is of great importance. Aryl iodides are essential building blocks for the synthesis of functional molecules, and efficient methods for their synthesis from chemical feedstocks are highly sought after. Here we report a low-cost decarboxylative iodination that occurs simply from readily available benzoic acids and I2. The reaction is scalable and the scope and robustness of the reaction is thoroughly examined. Mechanistic studies suggest that this reaction does not proceed via a radical mechanism, which is in contrast to classical Hunsdiecker-type decarboxylative halogenations. In addition, DFT studies allow comparisons to be made between our procedure and current transition-metal-catalyzed decarboxylations. The utility of this procedure is demonstrated in its application to oxidative cross-couplings of aromatics via decarboxylative/C-H or double decarboxylative activations that use I2 as the terminal oxidant. This strategy allows the preparation of biaryls previously inaccessible via decarboxylative methods and holds other advantages over existing decarboxylative oxidative couplings, as stoichiometric transition metals are avoided.
- Perry, Gregory J. P.,Quibell, Jacob M.,Panigrahi, Adyasha,Larrosa, Igor
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supporting information
p. 11527 - 11536
(2017/08/30)
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- Clean and Efficient Iodination of Thiophene Derivatives
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Iodination of thiophene derivatives is realized using a simple, fast, and efficient methodology. Iodination of thiophene and 2- or 3-substituted or 3,4-disubstituted thiophenes with N-iodosuccinimide (NIS) activated with 4-toluenesulfonic acid in ethanol gives pure iodinated products that require no further purification.
- Grolleau, Jérémie,Frère, Pierre,Gohier, Frédéric
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p. 3901 - 3906
(2015/12/18)
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- Regioselective oxidative Pd-catalysed coupling of alkylboronic acids with pyridin-2-yl-substituted heterocycles
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A total of 19 alkylated heterocycles (thiophenes, benzothiophenes, pyrroles, furans) were prepared (36-99% yield) from the respective pyridin-2-yl-substituted precursors employing alkylboronic acids as the C-H alkylating reagents in an oxidative (Ag2
- Wippich, Julian,Schnapperelle, Ingo,Bach, Thorsten
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supporting information
p. 3166 - 3168
(2015/06/11)
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- Green halogenation of aromatic heterocycles using ammonium halide and hydrogen peroxide in acetic acid solvent
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The green generation of X+ (X = Br, I) using hydrogen peroxide in aqueous acetic acid allows access to aromatic heterocyclic halides in yields and purities comparable to syntheses employing N-bromosuccinimide. In activated and unsubstituted thiophene rings, regioselectivity is quantitative for positions α to the sulfur; pyrroles also give quantitative reactions, at least initially. Deactivated rings, including furans and thiazoles, as well as thiophenes with strongly electron-withdrawing groups showed little to no reactivity under the conditions investigated. The reaction shows remarkable functional group tolerance (to alcohol, nitro, alkyl, halo, and carbonyl groups), as shown through reaction with substituted phenols. In all bromination reactions, reaction yields and regiochemistry were very similar to reactions involving N-bromosuccinimide in tetrahydrofuran solvent.
- D'Aleo, Danielle N.,Allard, Sheena R.,Foglia, Cassandra C.,Parent, Shawna L.M.,Rohr, David J.,Gottardo, Christine,MacKinnon, Craig D.
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supporting information
p. 679 - 683
(2013/08/23)
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- Dual selectivity: Electrophile and nucleophile selective cross-coupling reactions on a single aromatic substrate
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The development of a high yielding, both nucleophile and electrophile selective cross-coupling reaction with aromatic rings is presented. The reaction is general with respect to functional groups. Furthermore, the products still contain a boronic ester and a bromide. These two functional groups allow them to be easy-to-prepare, highly complex starting materials for further reactions, avoiding protecting group transformations.
- Heinrich, Annika C. J.,Thiedemann, Birk,Gates, Paul J.,Staubitz, Anne
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supporting information
p. 4666 - 4669
(2013/10/08)
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- Copper-catalyzed arene C-H bond cross-coupling
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A highly regioselective, one-pot sequential iodination-copper-catalyzed cross-coupling of arene C-H bonds has been developed affording an efficient method for biaryl synthesis.
- Do, Hien-Quang,Daugulis, Olafs
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supporting information; experimental part
p. 6433 - 6435
(2010/03/04)
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- Synthesis of "acetylene-expanded" tridentate ligands
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Synthetic routes to four new tridentate ligands with large cavities have been developed. Each ligand features two halides at the termini of the molecules that could be used for further elaboration of the system. Such compounds are ideal for encapsulating organoiodide guests using charge-transfer interactions.
- Holmes, Brian T.,Pennington, William T.,Hanks
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p. 447 - 455
(2007/10/03)
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- Bis-(trifluoroacetoxy)iodobenzene-iodine system: An efficient and selective reagent for iodination of thiophene derivatives
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Bis-(trifluoroacetoxy)iodobenzene-iodine system is a good iodinating reagent of thiophene derivatives giving products with iodine atom in α-position on the thiophene ring.
- D'Auria,Mauriello
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p. 4883 - 4884
(2007/10/02)
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- Biphasic Electrophilic Halogenation of Activated Aromatics and Heteroaromatics with N-Halosuccinimides Catalyzed by Perchloric Acid
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Catalytic amounts of 70percent perchloric acid (0.1 - 10, mostly 0.1 - 1, mol percent, based on substrate) initiate the regioselective halogenation of activated aromatics and heteroaromatics with N-halosuccinimide (NXS, X = Cl or Br) in two-phase solid-liquid systems (NXS/hexane or NXS/CCl4) at room temperature to give ring-halogenated products in high yields.For example, thiophene is transformed to 2-halo or 2,5-dihalo derivatives (yield 82-98percent) using 1 or 2 equiv of NXS, respectively.Unsymmetrical 2,5-dihalothiophenes are obtained in 70-82percent yield by reacting 2-halothiophenes with an appropriate NXS.The reaction of 3-bromothiophene with NBS affords 2,3-dibromothiophene in 93-99percent yield. 1,3-Dimethoxybenzene and 2,3-dimethylanisole are halogenated regiospecifically at the 4-position to give the corresponding products in 81-94percent yield.
- Goldberg, Yuri,Alper, Howard
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p. 3072 - 3075
(2007/10/02)
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- Thienyl-nonatetraenoic acid derivatives with anti-rheumatic activity
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Novel 9-thienyl-3,7-dimethyl-2,4,6,8-nonatetraenoic acids wherein the thiophene group is substituted with an alkyl and alkoxy group, and derivatives thereof can be used as disease modifying anti-rheumatic agents and immunosuppressants.
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- Kinetics of Iodination of Thiophene and 2-Halothiophenes
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The effect of substituents (Cl, Br and I) at the 2-position upon the rate of iodination with iodine monochloride in hydrochloric acid of thiophene at the 5-position, in 50percent aqueous acetic acid, had been studied at different temperatures.The rates and activation parameters for the 2-iodothiophene indicate an inductomeric mode of electron release by the iodine atom.
- Nair, M. R.
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p. 417 - 418
(2007/10/02)
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- Charge Density - Activation Energy Correlations in Electrophilic Bromination of Thiophenes
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Charge density calculations are made on eleven thiophenes by Hueckel LCAO MO and Del Re methods and correlated with experimental activation energies(Ea) obtained for the molecular bromination of these compounds.The need for the inclusion of ?-charges in any correlation of charge density with kinetic data is stressed. - Keywords: Charge density/ Activation energy / Bromination of thiophenes
- Nanjan, M. J.,Kannappan, V.,Ganesan, R.
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- Kinetics of Bromination of Certain Substituted Thiophenes in Solution
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The general features of the kinetics of bromination of thiophene and substituted thiophenes have been investigated in dry and 15percent aq. acetic acid (v/v) and the Arrhenius activation energy (Ea) accurately determined for ten thiophene derivatives and interpreted.The mechanism proposed is supported with the detection of a ?-complex between bromine and 2-bromothiophene.
- Kannappan, V.,Nanjan, M. J.,Ganesan, R.
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p. 1183 - 1187
(2007/10/02)
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