- On-surface synthesis of graphyne nanowires through stepwise reactions
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From an interplay of high-resolution UHV-STM imaging and DFT calculations, we have achieved on-surface synthesis of graphyne nanowires through stepwise reactions involving two different types of dehalogenative homocoupling reactions (i.e., C(sp3/sup
- Yu, Xin,Cai, Liangliang,Bao, Meiling,Sun, Qiang,Ma, Honghong,Yuan, Chunxue,Xu, Wei
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- Base-Promoted Synthesis of 2-Aryl Quinazolines from 2-Aminobenzylamines in Water
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A transition-metal-free procedure for the synthesis of a highly valuable class of heteroaromatics, quinazolines, was developed by using easily available 2-aminobenzylamines and α,α,α-trihalotoluenes. The transformation proceeded smoothly in the presence of only sodium hydroxide and molecular oxygen in water at 100 °C, furnishing a variety of 2-aryl quinazolines. The crystallization process of the crude reaction mixture for the purification of the solid products circumvents huge solvent-consuming workup and column chromatographic techniques, which make the overall process more sustainable and economical.
- Chatterjee, Tanmay,Kim, Dong In,Cho, Eun Jin
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p. 7423 - 7430
(2018/07/29)
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- Direct Formation of C?C Triple-Bonded Structural Motifs by On-Surface Dehalogenative Homocouplings of Tribromomethyl-Substituted Arenes
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On-surface synthesis shows significant potential in constructing novel nanostructures/nanomaterials, which has been intensely studied in recent years. The formation of acetylenic scaffolds provides an important route to the fabrication of emerging carbon nanostructures, including carbyne, graphyne, and graphdiyne, which feature chemically vulnerable sp-hybridized carbon atoms. Herein, we designed and synthesized a tribromomethyl-substituted compound. By using a combination of high-resolution scanning tunneling microscopy, non-contact atomic force microscopy, and density functional theory calculations, we demonstrated that it is feasible to convert these compounds directly into C?C triple-bonded structural motifs by on-surface dehalogenative homocoupling reactions. Concurrently, sp3-hybridized carbon atoms are converted into sp-hybridized ones, that is, an alkyl group is transformed into an alkynyl moiety. Moreover, we achieved the formation of dimer structures, one-dimensional molecular wires, and two-dimensional molecular networks on Au(111) surfaces, which should inspire further studies towards two-dimensional graphyne structures.
- Sun, Qiang,Yu, Xin,Bao, Meiling,Liu, Mengxi,Pan, Jinliang,Zha, Zeqi,Cai, Liangliang,Ma, Honghong,Yuan, Chunxue,Qiu, Xiaohui,Xu, Wei
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supporting information
p. 4035 - 4038
(2018/03/21)
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- Preparation method of diaryl acetylene compounds
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The invention relates to preparation of an organic compound, and aims to provide a preparation method of diaryl acetylene compounds. The preparation method includes steps of adding associated tribromomethylarene compound and copper in a reactor to perform deoxidizing treatment; dissolving polyamine in a proper amount of anhydrous and oxygen-free solvent, and then adding to the reactor; performingcoupling reaction at 30-80DEG C for 3-12 hours; separating and purifying to obtain diaryl acetylene compounds. The preparation is gentle in synthesis condition and the reaction has good compatibilityto different functional groups; the raw material associated tribromomethylarene compound is convenient to compound and has different substituent groups and variable structure; by adopting one raw material, high-quality product can be obtained through simple treatment, and the output is high; by adopting two different raw materials, the asymmetrical diaryl acetylene compound can be prepared.
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Paragraph 0057; 0058
(2018/05/16)
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- Catalytic halodefluorination of aliphatic carbon-fluorine bonds
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A variety of halosilanes, in conjunction with aluminum catalysts, convert fluorocarbons into higher halocarbons. Bromination and iodination of fluorocarbons are more effective than chlorination in terms of yield and activity. The mechanism for the reaction is investigated utilizing experimental and computational evidence and preliminary results suggest an alternate mechanism to that reported for the related hydrodefluorination reaction.
- Goh, Kelvin K.K.,Sinha, Arup,Fraser, Craig,Young, Rowan D.
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p. 42708 - 42712
(2016/05/19)
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- LEWIS ACID CATALYZED HALOGENATION OF ACTIVATED CARBON ATOMS
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A practical and efficient method for halogenation of activated carbon atoms using readily available /V-haloimides and a Lewis acid catalyst has been disclosed. This methodology is applicable to a range of compounds and any halogen atom can be directly introduced to the substrate. The mild reaction conditions, easy workup procedure and simple operation make this method valuable from both an environmental and preparative point of view.
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Page/Page column 29-30
(2008/06/13)
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- Lewis acid catalyzed highly selective halogenation of aromatic compounds
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A simple and efficient procedure for the halogenation of aromatic compounds with NCS, NBS, NIS and NFSI in the presence of catalytic amount of ZrCl 4 is described. Chlorination, bromination, iodination and fluorination of various aromatic compounds are performed with high selectivity under mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Zhang, Yanhua,Shibatomi, Kazutaka,Yamamoto, Hisashi
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p. 2837 - 2842
(2007/10/03)
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- Preparation of α, α-difluoroalkanesulfonic acids
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Chlorodifluoromethanesulfonic acid (1) was prepared using a new procedure starting from perchloromercaptan, which is readily obtained from chlorination of CS2. Modified Swarts reaction transformed N, N-diethyl trichloromethanesulfenamide into N, N-diethyl chlorodifluoromethanesulfenamide, and the latter species was further oxidized and hydrolyzed into chlorodifluoromethanesulfonic acid. The preparations of other two new α,α-difluoroalkanesulfonic acids, phenyl difluoromethanesulfonic acid (2) and 2-phenyl-1,1,2,2, -tetrafluoroethanesulfonic acid (3), are also disclosed. The acids 2 and 3 are stable in the forms of sodium (lithium) salts or in aqueous solutions; however, the pure forms of 2 and 3 can readily undergo defluorinations. 1-3 and their salts have potential applications as superacid catalysts and lithium battery electrolytes.
- Prakash, G.K. Surya,Hu, Jinbo,Simon, Jurgen,Bellew, Donald R.,Olah, George A.
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p. 595 - 601
(2007/10/03)
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- Photothermal Side-Chain Bromination of Methyl-, Dimethyl-, and Trimethylbenzenes with N-Bromosuccinimide
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Tri- and dibromination of methyl-, dimethyl-, and trimethylbenzenes with N-bromosuccinimide were accomplished by photothermal reaction with a tungsten lamp in carbon tetrachloride or benzene. (Dibromomethyl)arenes and (tribromomethyl) derivatives were produced depending upon a solvent used and a substituent on the benzene ring.In the bromination of methylbenzenes without a substituent on the ortho-position, (tribromomethyl)benzenes were formed.On the other hand, ortho-substituted methylbenzenes gave (dibromomethyl)benzenes. α,β-Dibromo-1,2-diarylstilbenes were formed via the debrominative carbon-carbon coupling reaction of ...
- Mataka, Shuntaro,Liu, Guo-Bin,Sawada, Tsuyoshi,Kurisu, Masayoshi,Tashiro, Masashi
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p. 1113 - 1119
(2007/10/02)
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- THE BROMINATION OF METHYLARENES WITH NBS BY IRRADIATION USING A TUNGSTEN LAMP. PREPARATION OF BENZOTRIBROMIDES
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Bromination of toluene and its meta- and para-substituted derivatives with NBS by irradiation using a tungsten lamp gave benzotribromides and cis- and trans-1,2-dibromo-1,2-diaryl-ethylenes, while ortho-substituted toluenes gave benzal bromides. o-Xylene gave tetra- and pentabromides and m-xylene afforded a mixture of dibromodiarylethylenes.
- Mataka, Shuntaro,Kurisu, Masayoshi,Takahashi, Kazufumi,Tashiro, Masashi
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p. 1969 - 1972
(2007/10/02)
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