- Piers′ Borane-Induced Tetramerization of Arylacetylenes
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We herein report that the reaction of Piers′ borane, i. e. HB(C6F5)2, with an excess of arylacetylenes at room temperature leads to tetramerization of the acetylene and the diastereoselective formation of boryl-substituted
- Hasenbeck, Max,Müller, Tizian,Averdunk, Arthur,Becker, Jonathan,Gellrich, Urs
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- Synthesis and Photochemical Application of Hydrofluoroolefin (HFO) Based Fluoroalkyl Building Block
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A novel fluoroalkyl iodide was synthesized on multigram scale from refrigerant gas HFO-1234yf as cheap industrial starting material in a simple, solvent-free, and easily scalable process. We demonstrated its applicability in a metal-free photocatalytic ATRA reaction to synthesize valuable fluoroalkylated vinyl iodides and proved the straightforward transformability of the products in cross-coupling chemistry to obtain conjugated systems.
- Varga, Bálint,Tóth, Balázs L.,Béke, Ferenc,Csenki, János T.,Kotschy, András,Novák, Zoltán
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supporting information
p. 4925 - 4929
(2021/07/01)
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- Synthesis of Phenanthrenes via Palladium-Catalyzed Three-Component Domino Reaction of Aryl Iodides, Internal Alkynes, and o-Bromobenzoic Acids
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A new palladium-catalyzed domino alkyne insertion/C-H activation/decarboxylation sequence has been developed, which provides an efficient approach for synthesizing a variety of functionalized phenanthrenes in moderate to good yields. The method shows broad substrate scope and good functional group tolerance by employing readily available materials, including aryl iodides, internal alkynes, and o-bromobenzoic acids, as three-component coupling partners.
- Deng, Guobo,Liang, Yun,Luo, Xiai,Yang, Xiumei,Yang, Yuan,Yang, Yuzhong,Zhou, Liwei
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supporting information
p. 1223 - 1230
(2020/04/15)
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- Trans Influence of Ligands on the Oxidation of Gold(I) Complexes
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Gold(I) complexes are considered active species toward oxidative addition; current understanding indicates a different mechanism in contrast to other late transition metals, but a rational understanding of the reactivity profile is lacking. Herein, we propose that the accessibility of the gold(I) center to tri- or tetra-coordination is critical in the oxidative process involving a tri- or tetra-coordinate gold(I) with the oxidizing reagent as one of the ligands as an intermediate. A computational study of the geometry of (Phen)R3PAu(I)NTf2 complexes shows that the accessibility of such tricoordinate species shows a good correlation with the "trans influence" of phosphine ligands: the weak σ-donating phosphine ligands promote tricoordination of gold(I) complexes. The oxidative addition to the asymmetric tricoordinate (Phen)R3PAu(I)NTf2 complexes with alkynyl hypervalent iodine reagents was built. The kinetic profile of the oxidative addition exhibits a good relationship to the Hammett substituent parameter (ρ = 3.75, R2 = 0.934), in which the gold(I) complexes bearing less σ-donating phosphine ligands increase the rate of oxidative addition. The positive ρ indicates a high sensitivity of the oxidative addition to the trans influence. The reactivity profile of oxidative addition to a linear bis(pyridine)gold(I) complex further supports that the oxidative addition to gold(I) complexes is promoted by ligands with small trans influence.
- Yang, Yangyang,Eberle, Lukas,Mulks, Florian F.,Wunsch, Jonas F.,Zimmer, Marc,Rominger, Frank,Rudolph, Matthias,Hashmi, A. Stephen K.
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supporting information
p. 17414 - 17420
(2019/10/28)
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- Palladium-Catalyzed One-Pot Four-Component Synthesis of β-Cyano-α,β-unsaturated Ketones Using Calcium Carbide as an Acetylene Source and Potassium Hexacyanoferrate(II) as an Eco-Friendly Cyanide Source
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Palladium-catalyzed one-pot four-component synthesis of β-cyano-α,β-unsaturated ketones by the reactions of aryl halides, calcium carbide, potassium hexacyanoferrate(II) and aroyl chlorides is described. The salient features of this protocol are the direct use of easy-to-handle acetylene source and eco-friendly cyanide source, wide scope of substrates with good functional group tolerance, and simple work-up procedure. (Figure presented.).
- Lu, Hao,Li, Zheng
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supporting information
p. 4474 - 4482
(2019/08/20)
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- BF3·OEt2-Promoted Propargyl Alcohol Rearrangement/[1,5]-Hydride Transfer/Cyclization Cascade Affording Tetrahydroquinolines
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An efficient BF3·OEt2-mediated propargyl alcohol rearrangement/[1,5]-hydride transfer/cyclization cascade for the synthesis of tetrahydroquinoline derivatives has been described. The substituents adjacent to triple bonds play an important role in the formation of ketones (via [1,3]-hydroxyl shift) or alkenyl fluorides which are products of formal trans-carbofluorination of internal alkynes. This method provides a rapid access to diverse heterocycles in moderate to excellent yields.
- Zhao, Shuang,Wang, Xiaoyang,Wang, Pengfei,Wang, Guangwei,Zhao, Wentao,Tang, Xiangyang,Guo, Minjie
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supporting information
p. 3990 - 3993
(2019/06/14)
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- An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
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We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
- Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
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p. 2250 - 2255
(2018/02/23)
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- A practical non-metal catalytic silicon of the amino protection of the new method (by machine translation)
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The invention relates to a high efficiency, mild organic silicon reagent carbon silicon key fracture of the new method. The method of this reaction to the alkali is cheap and easy to obtain metal catalyst, in order to common commercial solvent as a reaction solvent and a hydrogen source, in the air and in the under mild conditions can be successfully catalytic trimethyl aryl silicon reagent or aryl alkyne base silicon reagent selectively generating carbon silicon key cracking hydrogenation reaction, the substrate universality is wide, functional group compatibility outstanding. The first innovative to realize the non-transition metal catalyzed carbon silicon key breaking reaction, also overcome the traditional method requires the use of greatly excessive inorganic alkali or an expensive metal catalyst to the limitation of the silicon of the amino protection, for the laboratory preparation and industry in the production of the organosilicon group deprotection provides a completely new strategy. (by machine translation)
- -
-
Paragraph 0058; 0059
(2018/04/01)
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- Reaction discovery using acetylene gas as the chemical feedstock accelerated by the stop-flow micro-tubing reactor system
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Acetylene gas has been applied as a feedstock under transition-metal catalysis and photo-redox conditions to produce important chemicals including terminal alkynes, fulvenes, and fluorinated styrene compounds. The reaction discovery process was accelerated through the use of stop-flow micro-tubing reactors. This reactor prototype was developed by joining elements from both continuous micro-flow and conventional batch reactors, which was convenient and effective for gas/liquid reaction screening. Notably, the developed transformations were either inefficient or unsuccessful in conventional batch reactors. Its success relies on the unique advantages provided by this stop-flow micro-tubing reactor system.
- Xue, Fei,Deng, Hongping,Xue, Chengwen,Mohamed, Dara Khairunnisa Binte,Tang, Karen Yuanting,Wu, Jie
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p. 3623 - 3627
(2017/07/11)
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- 2-Aryl-8-aza-3-deazaadenosine analogues of 5′-O-[N-(salicyl)sulfamoyl]adenosine: Nucleoside antibiotics that block siderophore biosynthesis in Mycobacterium tuberculosis
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A series of 5′-O-[N-(salicyl)sulfamoyl]-2-aryl-8-aza-3-deazaadenosines were designed to block mycobactin biosynthesis in Mycobacterium tuberculosis (Mtb) through inhibition of the essential adenylating enzyme MbtA. The synthesis of the 2-aryl-8-aza-3-deaz
- Krajczyk, Anna,Zeidler, Joanna,Januszczyk, Piotr,Dawadi, Surendra,Boshoff, Helena I.,Barry, Clifton E.,Ostrowski, Tomasz,Aldrich, Courtney C.
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supporting information
p. 3133 - 3143
(2016/07/06)
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- Cleavage of the Carbon–Carbon Triple Bonds of Arylacetylenes for the Synthesis of Arylnitriles without a Metal Catalyst
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Cleavage of the carbon–carbon triple bonds of alkynes was achieved, which led to the synthesis of arylnitriles under transition-metal-free conditions. A vast range of terminal alkyne substrates underwent this reaction to provide the corresponding nitriles in moderate to good yields with good functional group tolerance.
- Lin, Yuanguang,Song, Qiuling
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supporting information
p. 3056 - 3059
(2016/07/12)
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- Efficient synthesis of N-arylsulfonyl-1,2,3-triazoles from 1,1-dibromo-2-arylethylenes
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N-arylsulfonyl-1,2,3-triazoles were synthesized from 1,1-dibromo-2-arylethylenes via a one-pot reaction involving the Cs2CO3-mediated dehydrobromination process of the dibromoalkenes to produce alkynes followed by the Cu(I)-catalyzed Huisgen cycloaddition of the alkyne intermediates with tosyl azide.
- Xu, Wenjing,Zhang, Wensheng,Zhang, Fei
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p. 165 - 167
(2016/07/06)
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- Synthesis of 1-arylsulfonyl-1,2,3-triazoles from (Z)-arylvinyl bromides by sequential elimination–cycloaddition reaction
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[Figure not available: see fulltext.]Efficient synthesis of 1-arylsulfonyl-1,2,3-triazoles from easily available (Z)-arylvinyl bromides is described. The sequential reaction involves elimination of HBr from (Z)-arylvinyl bromides promoted by KOH and copper-catalyzed (3+2) cycloaddition reaction between the alkyne intermediates and sulfonyl azides.
- Zhang, Wensheng,Xu, Wenjing
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p. 192 - 195
(2016/07/28)
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- One-pot synthesis of 1,3-enynes with a CF3 group on the terminal sp2 carbon by an oxidative Sonogashira cross-coupling reaction
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Oxidative Sonogashira cross-coupling reactions of (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane with arylacetylene were achieved using silver fluoride and a palladium catalyst, to afford high yields of various 1,3-enynes with a CF3 group on the terminal sp2 carbon. Silver fluoride promoted C-Si bond dissociation and oxidation of palladium, enabling catalytic use of palladium.
- Ikeda, Akari,Omote, Masaaki,Kusumoto, Kana,Tarui, Atsushi,Sato, Kazuyuki,Ando, Akira
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supporting information
p. 8886 - 8892
(2015/08/24)
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- Reactivity switch enabled by counterion: Highly chemoselective dimerization and hydration of terminal alkynes
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A counterion-controlled reactivity tuning in Pd-catalyzed highly chemoselective and regioselective dimerization and hydration of terminal alkynes is reported. The use of acetate as counterion favors the formation of an alkenyl alkynyl palladium intermediate which forms hitherto less reported 1,3-diaryl-substituted conjugated enynes after reductive elimination. Using chloride, which is a better leaving group, leads to anion exchange on the alkenylpalladium intermediate with hydroxide which after reductive elimination and tautomerization delivered the hydration products.
- Xu, Caixia,Du, Weiyuan,Zeng, Yi,Dai, Bin,Guo, Hao
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supporting information
p. 948 - 951
(2014/03/21)
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- Investigation of quantitative structure-reactivity relationships in the aliphatic Claisen rearrangement of bis-vinyl ethers reveals a dipolar, dissociative mechanism
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Kinetic investigations of substituent effects in the thermal rearrangement of bis-vinyl ether substrates are reported. Findings indicate that the influence of the various substituent patterns on the rate of rearrangement in these compounds differs from that documented in the literature for the analogous [3,3]-sigmatropic rearrangement of allyl vinyl ethers. In addition, the thermochemical data collected suggests the existence of a dissociative transition state with significant dipolar character. These findings provide a unique contribution to the already extensive body of literature dedicated to mechanistic investigation of the Claisen rearrangement of aliphatic allyl vinyl ethers.
- O'Rourke, Natasha F.,Wulff, Jeremy E.
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p. 1292 - 1308
(2014/03/21)
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- Pseudo five-component synthesis of 3-(hetero)arylmethyl-2,5-di(hetero)-aryl-substituted thiophenes via sonogashira-glaser cyclization sequence
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The Sonogashira-Glaser sequence combined with a microwave-assisted cyclization is a powerful tool to synthesize unsymmetrically substituted conjugated thiophenes. A variety of 3-(hetero)arylmethyl-2,5-di(hetero)aryl-substituted thiophenes could be synthesized in moderate to excellent yields using a single Pd/Cu catalyst system. The presented method is strikingly simple to perform using commercially available starting materials. The obtained trisubstituted oligothiophene derivatives are interesting molecules for materials science.
- Klukas, Fabian,Perkampus, J?rg,Urselmann, Dominik,Müller, Thomas J. J.
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p. 3415 - 3422
(2015/02/02)
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- Aerobic oxynitration of alkynes with tBuONO and TEMPO
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An efficient method for stereoselective nitroaminoxylation of alkyne has been reported. The reaction enjoys a broad substrate scope, good functional group tolerance, and high yields. Synthetically useful α-nitroketones can be accessed through these products in a single step.
- Dutta, Uttam,Maity, Soham,Kancherla, Rajesh,Maiti, Debabrata
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supporting information
p. 6302 - 6305
(2015/02/19)
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- Synthesis of 1,2,3-triazoles from azide-derivatised aminocyclitols by catalytic diazo transfer and CuAAC click chemistry
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CuII-catalysed diazo transfer and CuI-catalysed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) "click chemistry" were used to synthesis C7N aminocyclitol-derivatised 1,2,3-triazoles. In the course of this work, the -N=N- moiety was transferred onto C7N aminocyclitols such as validamine, valienamine and valiolamine by employing imidazole-1-sulfonyl azide as the diazo transfer reagent with catalysis by CuII, ZnII and NiII, in moderate to good yields. The obtained azidocyclitols were coupled with various terminal alkynes under modified Meldal's conditions with good to excellent yields. The stereo- and regiochemistry of the products were confirmed by 2D-NMR (NOESY and HMBC). One-pot syntheses of the corresponding 1,2,3-triazoles, as safer and more efficient procedures, were also investigated and gave moderate to good yields. Copyright
- Ji, Li,Zhou, Guo-Quan,Qian, Chao,Chen, Xin-Zhi
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supporting information
p. 3622 - 3636
(2014/06/23)
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- "quick and click" assembly of functionalised indole rings via metal-promoted cyclative tandem reactions
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An efficient and convenient synthesis of a variety of decorated indoles using a three-component tandem metal-catalysed process is described. We propose here a new "synthetic kit" that allows for the "quick and click" assembly of indole rings using readily available, and inexpensive starting materials under environmentally friendly reaction conditions. This journal is
- Capitta, Francesca,De Luca, Lidia,Porcheddu, Andrea
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p. 59297 - 59301
(2015/02/19)
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- Rapid discovery of a novel series of Abl kinase inhibitors by application of an integrated microfluidic synthesis and screening platform
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Drug discovery faces economic and scientific imperatives to deliver lead molecules rapidly and efficiently. Using traditional paradigms the molecular design, synthesis, and screening loops enforce a significant time delay leading to inefficient use of data in the iterative molecular design process. Here, we report the application of a flow technology platform integrating the key elements of structure-activity relationship (SAR) generation to the discovery of novel Abl kinase inhibitors. The platform utilizes flow chemistry for rapid in-line synthesis, automated purification, and analysis coupled with bioassay. The combination of activity prediction using Random-Forest regression with chemical space sampling algorithms allows the construction of an activity model that refines itself after every iteration of synthesis and biological result. Within just 21 compounds, the automated process identified a novel template and hinge binding motif with pIC50 > 8 against Abl kinase - both wild type and clinically relevant mutants. Integrated microfluidic synthesis and screening coupled with machine learning design have the potential to greatly reduce the time and cost of drug discovery within the hit-to-lead and lead optimization phases.
- Desai, Bimbisar,Dixon, Karen,Farrant, Elizabeth,Feng, Qixing,Gibson, Karl R.,Van Hoorn, Willem P.,Mills, James,Morgan, Trevor,Parry, David M.,Ramjee, Manoj K.,Selway, Christopher N.,Tarver, Gary J.,Whitlock, Gavin,Wright, Adrian G.
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supporting information
p. 3033 - 3047
(2013/05/22)
-
- Catalytic cascade hydroalkoxylation/isomerization/[4 + 2] cycloaddition using enyne alcohols as latent dienes or dienophiles
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Enyne alcohols can react as precursors of either dienes or dienophiles with different substrates after hydroxylation and isomerization by gold catalysis. As such, oxa-bridged tricyclo[5.2.2.02,6]undec-8-ene-3,5-dione derivatives have been obtained by the Diels-Alder reaction and tetrahydro-1H-furo[3,4-c]pyran derivatives could be accessed by the hetero-Diels-Alder cycloaddition.
- Guo, Rui,Li, Kang-Nan,Gong, Liu-Zhu
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supporting information
p. 6707 - 6712
(2013/10/01)
-
- Copper-mediated trifluoromethylation of propiolic acids: Facile synthesis of α-trifluoromethyl ketones
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Copper-mediated decarboxylative trifluoromethylation provides a new protocol for the efficient preparation of α-trifluoromethyl ketones from propiolic acids. It was found that water is involved as a reactant in the reaction, which is significantly different from the previously reported decarboxylative fluoroalkylation reactions.
- He, Zhengbiao,Zhang, Rui,Hu, Mingyou,Li, Lingchun,Ni, Chuanfa,Hu, Jinbo
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p. 3478 - 3483
(2013/11/19)
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- Formation of quaternary stereogenic centers by copper-catalyzed asymmetric conjugate addition reactions of alkenylaluminums to trisubstituted enones
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Alkenylaluminums undergo asymmetric copper-catalyzed conjugate addition (ACA) to β-substituted enones allowing the formation of stereogenic all-carbon quaternary centers. Phosphinamine-copper complexes proved to be particularly active and selective compared with phosphoramidite ligands. After extensive optimization, high enantioselectivities (up to 96 % ee) were obtained for the addition of alkenylalanes to β-substituted enones. Two strategies for the generation of the requisite alkenylaluminums were explored allowing for the introduction of aryl- and alkyl-substituted alkenyl nucleophiles. Moreover, alkyl-substituted phosphinamine (SimplePhos) ligands were identified for the first time as highly efficient ligands for the Cu-catalyzed ACA. Chiral synthesis made easy: The copper-catalyzed conjugate addition of alkenylaluminum reagents to 3-substituted cyclic enones allows for the formation of all-carbon chiral quaternary centers (see scheme; CuTC=copper(I) thiophene-2-carboxylate). Chiral phosphinamine (SimplePhos) ligands were found to be highly efficient for this transformation.
- Mueller, Daniel,Alexakis, Alexandre
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supporting information
p. 15226 - 15239
(2013/11/06)
-
- Efficient approach to 1,2-diazepines via formal diazomethylene insertion into the C-C bond of cyclobutenones
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Efficient monocyclic 1,2-diazepine formation via a tandem electrocyclization reaction of cyclobutenones with lithiodiazoacetate is demonstrated. The reaction proceeds through an oxy anion-accelerated 4π-ring opening of cyclobutene followed by an 8π-ring closure of the resultant oxy anion-substituted diazo-diene under mild conditions to furnish a 1,2-diazepine via formal diazomethylene insertion into the C-C bond of cyclobutenone.
- Sugimoto, Kenji,Hayashi, Rie,Nemoto, Hideo,Toyooka, Naoki,Matsuya, Yuji
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supporting information; experimental part
p. 3510 - 3513
(2012/07/31)
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- Rapid consecutive three-component coupling-Fiesselmann synthesis of luminescent 2,4-disubstituted thiophenes and oligothiophenes
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(Hetero)aroyl chlorides, alkynes, and ethyl 2-mercapto acetate can be reacted in a consecutive three-component synthesis to give 2,4-disubstituted thiophene 5-carboxylates in good to excellent yields. In the sense of a pseudo-five-component reaction highly blue luminescent symmetrical terthiophenes and a quinquethiophene can be synthesized in excellent yield.
- Teiber, Marco,Mueller, Thomas J. J.
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supporting information; experimental part
p. 2080 - 2082
(2012/03/10)
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- One-pot, two-step conversion of aldehydes to phosphonyl- and sulfonylpyrazoles using Bestmann-Ohira reagent
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A one-pot, two-step, three-component method for the conversion of commercially available aldehydes to phosphonylpyrazoles has been developed, demonstrating, for the first time, the dual reactivity of the Bestmann-Ohira reagent (BOR) in a single-pot transformation. This method, extended to the synthesis of sulfonylpyrazoles by employing BOR in the first step and a diazomethyl sulfone in the second step, is complementary, with regard to regioselectivity, to the previous methods for the synthesis of such functionalized pyrazoles.
- Kumar, Rahul,Verma, Deepti,Mobin, Shaikh M.,Namboothiri, Irishi N. N.
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supporting information; experimental part
p. 4070 - 4073
(2012/09/21)
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- Synthesis of aryl alkynyl carboxylic acids and aryl alkynes from propiolic acid and aryl halides by site selective coupling and decarboxylation
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The coupling of propiolic acid with aryl iodides afforded the aryl alkynyl carboxylic acids and aryl alkynes in generally good yields. Aryl alkynyl carboxylic acids were obtained when the reaction was performed in the presence of Pd(PPh3)2Cl2 (2.5 mol %), dppb (5.0 mol %) and DBU (5 equiv) at 50°C. For the synthesis of the terminal aryl alkynes, the reaction was conducted in the presence of Pd(PPh3) 2Cl2 (2.5 mol %), dppb (5.0 mol %), DBU (5.0 equiv), and Cu(acac)2 (10 mol %) at 25°C for 5 h, and further reacted at 60°C for 6 h.
- Park, Kyungho,Palani, Thiruvengadam,Pyo, Ayoung,Lee, Sunwoo
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experimental part
p. 733 - 737
(2012/03/08)
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- Convenient synthesis of terminal alkynes from anti-3-aryl-2,3- dibromopropanoic acids using a K2CO3/DMSO system
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A convenient, efficient, and generally applicable method was developed for the synthesis of terminal alkynes from anti-3-aryl-2,3-dibromopropanoic acids in the presence of DMSO and K2CO3.
- Cheng, Xuezhi,Jia, Jun,Kuang, Chunxiang
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p. 2350 - 2354
(2012/02/03)
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- Cs2CO3-mediated synthesis of terminal alkynes from 1,1-dibromo-1-alkenes
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An unprecedented route to prepare terminal alkynes from 1,1-dibromo-1-alkenes mediated by Cs2CO3 was proven. 1,1-Dibromo-1-alkenes bearing various functional groups were efficiently converted to corresponding terminal alkynes in moderate to excellent yields.
- Zhao, Ming,Kuang, Chunxiang,Yang, Qing,Cheng, Xuezhi
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scheme or table
p. 992 - 994
(2011/03/22)
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- Stereospecific approach to α,β-disubstituted nitroalkenes via coupling of α-bromonitroalkenes with boronic acids and terminal acetylenes
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(Z)-α-Bromo-β-substituted nitroethylenes undergo facile Suzuki coupling with aryl, heteroaryl, and vinylboronic acids in the presence of Pd(PPh3)4 as catalyst to afford (E)-α,β-disubstituted nitroethylenes in high yield (up to 95%) and complete specificity. Similar coupling of α-bromonitroethylenes with terminal acetylenes (Sonogashira coupling) provides a novel route to (E)-nitroenynes. These Pd-catalyzed coupling methods offer a convenient and stereospecific entry into a diverse array of synthetically and biologically useful α,β-disubstituted nitroethylenes.
- Ganesh, Madhu,Namboothiri, Irishi N.N.
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p. 11973 - 11983
(2008/03/13)
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- Systematic studies on photoluminescence of oligo(arylene-ethynylene)s: Tunability of excited states and derivatization as luminescent labeling probes for proteins
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Functionalized oligo(phenylene-ethynylene)s (OPEs) with different conjugation lengths, p-X(C6H4C≡C) nSiMe3 (n = 1-4; X = NH2, NMe2, H) were synthesized by Sonogashira coupling of (phenylene-ethynylene)s and 1-iodo-4-(trimethylsilylethynyl)benzene, followed by desilylation of the p-substituted (trimethylsilylethynyl)benzenes with potassium hydroxide. The photoluminescent properties for the OPE series with different chain lengths and their solvatochromic responses were examined. The absorption maxima were red-shifted with increasing numbers of -(C6H4C≡C)- units (n), and a linear plot of the absorption energy maxima vs. 1/n was obtained for each series. The emission spectra in dichloromethane showed a broad and structureless band, the energies of which (in wavenumbers) also fit linearly with 1/n. Both the absorption and emission wavelength maxima of the NH2- and NMe2-substituted OPEs exhibited significant solvent dependence, whereas the parent OPEs (X = H) showed only minor shifts of the λmax values in different solvents. Substituent effects upon the photoluminescent characteristics of the OPEs and the tunability of the excited states were examined with the p-X(C6H4C≡C) nSiMe3 (n = 2, 3; X = NH2, NMe2, H, SMe, OMe, OH, and F) series. The H- and F-substituted counterparts exhibited high-energy vibronically structured emissions attributed to the 3(ππ*) excited states of the (arylene-ethynylene) backbone. For compounds bearing NH2 and NMe2 groups, a broad red-shifted emission with a remarkable Stokes shift from the respective absorption maximum was observed, which can be assigned to an n → π* transition. The n → π* assignment was supported by MO calculations on the model compounds p-X(C6H4C≡C) 2SiH3 (X = NH2, H). Functionalization of the oligo(arylene-ethynylene)s with the N-hydroxysuccinimidyl (NHS) moiety enabled covalent attachment of the fluorophore to HSA protein molecules. A series of fluorescent labels, namely p-X(C6H4C≡C) n-C6H4NHS, (n = 1, X = NH2, NMe 2, SMe, OMe, OH, F; n = 2, X = NH2, NMe2) and p-Me2NC6H4C≡C(C4H 2S)-C≡CC6H4NHS were synthesized, and their conjugates with HSA (human serum albumin) were characterized by MALDI-TOF mass spectrometry, UV/Vis absorption spectroscopy, and gel electrophoresis. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Zhi, Yong-Gang,Lai, Siu-Wai,Chan, Queenie K.-W.,Law, Yuen-Chi,Tong, Glenna S.-M.,Che, Chi-Ming
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p. 3125 - 3139
(2007/10/03)
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- Pyrazolo[1,5-a]pyridines as p38 kinase inhibitors
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(Chemical Equation Presented) A convergent synthesis of substituted pyrazolo[1,5-a]pyridines has been achieved either via a regioselective [3 + 2] cycloaddition of N-aminopyridines with alkynes or by thermal cyclization of disubstituted azirines. Subseque
- Stevens, Kirk L.,Jung, David K.,Alberti, Michael J.,Badiang, Jennifer G.,Peckham, Gregory E.,Veal, Jim M.,Cheung, Mui,Harris, Philip A.,Chamberlain, Stanley D.,Peel, Michael R.
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p. 4753 - 4756
(2007/10/03)
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- A one-pot synthesis of terminal alkynes from anti-3-aryl-2,3- dibromopropanoic acids under microwave irradiation
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A facile one-pot synthesis of terminal alkynes was achieved by microwave irradiation of a mixture of anti-3-aryl-2,3-dibromopropanoic acids, Et 3N and DMF and subsequent irradiation in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This method requires short reaction time (1-2 min) and gives terminal alkynes in high yields. Copyright
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
-
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- Novel 3-phenylprop-2-ynylamines as inhibitors of mammalian squalene epoxidase.
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The synthesis of a novel series of 3-phenylprop-2-ynylamines as selective mammalian squalene epoxidase inhibitors is described. Structure activity relationship studies led to the discovery of compound 19, 1-[3-(3,5-dichlorophenyl)-prop-2-ynyl]-3- methylpiperidine hydrochloride with an IC50 of 2.8 +/- 0.6 microM against rat liver squalene epoxidase. Against 23 strains of fungal squalene epoxidase compound 19 was found to be inactive.
- Musso, David L,Clarke, Morris J,Kelley, James L,Boswell, G Evan,Chen, Grace
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p. 498 - 506
(2007/10/03)
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- An improved procedure for the preparation of aryl- and hetarylacetylenes
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A number of relatively volatile acetylenes RC ≡ CH (R = aryl or hetaryl) have been prepared with high yields by heating a mixture of the corresponding alcohols RC ≡ CC(CH3)2OH and paraffin oil with small amounts of powdered potassium hydroxide in vacuum. The alcohols were obtained by Pd/Cu-catalyzed cross coupling of aryl or hetaryl halides RX (X = Br, in one case I) with the commercially available HC ≡ CC(CH3)2OH.
- Mal'Kina,Brandsma,Vasilevsky,Trofimov
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p. 589 - 590
(2007/10/03)
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- Design of multilayered polymeric dielectric insulators for advanced microelectronics packaging
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2,2-Bis[ 4-{ (4-fluorophenyl)buta-1,3-diynyl} phenyloxyphenyl] hexafluoropropane and co-polymer of 1,4-bis(4-fluorophenyl)buta-1,3-diyne and hexafluorobisphenol-A were prepared for the use as photosensitive multilayered polymeric dielectric insulators. Th
- Park,Chiesel,Economy
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p. 351 - 363
(2007/10/02)
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- Preparation of Fluorine-Containing Phenylacetylenes by the Method of Introduction of the Ethynyl Group Using 1,1-Dichloro-2,2-difluroethene
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Phenylacetylenes (ArCCH) having fluoro- or trifluoromethyl substituents (o-, m-, p-F; o-, m-, p-CF3; 2,4-, 2,5-, 2,6-, 3,5-(CF3)2) have been prepared from bromobenzenes (ArBr) and benzenes (ArH) using 1,1,-dichloro-2,2-difluoroethene (1) by a two-step route: ArLi or ArMgBr->ArCF=CCl2->ArCCLi.Upon careful treatment at -70 deg C with 1, o-fluorophenyllithium gave o-FC6H4CF=CCl2 in good yield, together with benzyne-derived products, such as o-(o-FC6H4)C6H4CF=CCl2.Lithiation of m-bis(trifluoromethyl)benzene at 0 deg C for 9 h (24 h) followed by treatment with bromine gave 1-bromo-2,4-, 2,6-, and 3,5-bis(trifluoromethyl)benzene in 35 (38), 31 (36), and 8percent (6percent) yield, respectively.
- Kodaira, Kazuo,Okuhara, Kunio
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p. 1625 - 1632
(2007/10/02)
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- Stereomutation in the Seyferth Reaction
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The cyclopropanation reaction between dibromomethylene (:CBr2) from the Seyferth reagent (PhHgCBr3) and electron-deficient alkenes is nonstereospecific.Thus fumaronitrile, styrene-cis-β-d, and trans-1,2-dichloroethene give mixtures of the respective cis a
- Lambert, Joseph B.,Larson, Eric G.,Bosch, Richard J.,Vrucht, Mollie L. E. Te
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p. 5443 - 5447
(2007/10/02)
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- Choix des methodes pour la synthese univoque de carbures acetyleniques. Troisieme partie : Arylacetylenes et aryl-1 alcynes-1
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The range of applicability of six syntheses of pure alkynes with one aryl group has been defined; a short review of other possible procedures is included.We have specified the best method to obtain selectively the alkynes Ar-CCH and Ar-CC-R, according to the nature of the substituents of the aryl group and according to the developed structure of the R group.It is thus possible to recommend with the largest probability of success the method to obtain, in homogenous series, alkynes corresponding to still more complicated structures.
- Mesnard, Danielle,Bernadou, Francoise,Miginiac, Leone
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p. 3216 - 3245
(2007/10/02)
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