- Palladium (II) complexes chelated by 1-substituted-4-pyridyl-1H-1,2,3-triazole ligands as catalyst precursors for selective ethylene dimerization
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A series of neutral as well as cationic palladium methyl complexes bearing 1-substituted-4-pyridyl-1H-1,2,3-triazole ligands were prepared and fully characterized by a range of analytical techniques. Conventional and 2D NMR spectroscopy as well as single-crystal X-ray diffraction analysis unambiguously determined the molecular structure of the complexes. The neutral complexes activated by methylaluminoxane were found to be effective catalysts in the ethylene dimerization reaction. The catalyst performance of the in-situ-generated active species was compared with the discrete cationic complexes of the same ligand scaffold. Activities and selectivities for the two systems were remarkably similar, pointing to similarities in the nature of the active species. Both catalytic systems showed a strong correlation of activity and selectivity with the nature of the ligand scaffold. Highest activities were attained when electron-withdrawing groups were incorporated into the triazole ring, while increasing steric bulk in the ortho-position on the pyridyl ring of the ligand led to the almost exclusive dimerization of ethylene with selectivities up to 94% observed toward 1-butene.
- Joseph, Mohammed Cassiem,Swarts, Andrew John,Mapolie, Selwyn Frank
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Read Online
- Synthesis and characterization of 2,5-bis(2-pyridyl)thiophene
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2-[2-(Trimethylsilyl)ethynyl] pyridine (6) was prepared in 95% yield by reaction of 2-bromopyridine with trimethylsilylacetylene in triethylamine in the presence of bis(triphenylphosphine)Palladium(II) chloride and Copper(I) iodide. Desilylation of (6) by refluxing with sodium hydroxide in methanol (yield 95%) of 2-ethynylpyridine (5). Oxidative coupling of (5) in pyridine by oxygen in the presence of Copper(I) chloride gives 70% yield of 1,4-bis(2-pyridyl)1,3-butadiyne (4). Reaction of 4 with sodium sulfide affords 100% of 2,5-bis(2-pyridyl) thiophene (1).
- Al-Taweel, Samir A.
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Read Online
- Regio- and stereoselective synthesis of bromoalkenes by homolytic hydrobromination of alkynes with hydrogen bromide
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Homolytic hydrobromination of terminal and internal alkynes with a commercially available solution of hydrogen bromide in acetic acid has been investigated for regio- and stereoselective synthesis of bromoalkenes. Under an aerobic atmosphere at room temperature, the reaction of ethynylarenes with a small excess of HBr efficiently gave (2-bromoethenyl)arenes with good to high E-selectivity. (Alk-1-ynyl)arenes, or internal alkynes bearing both phenyl and alkyl groups at the sp-carbons also underwent the air-initiated hydrobromination to exhibit high Z-selectivity under kinetic conditions using a half equivalent of HBr.
- Kumaki, Wataru,Kinoshita, Hidenori,Miura, Katsukiyo
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supporting information
(2022/03/07)
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- The synthesis of cyclometalated platinum(ii) complexes with benzoaryl-pyridines as C^N ligands for investigating their photophysical, electrochemical and electroluminescent properties
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A series of (C^N)Pt(acac)-type complexes has been successfully synthesized with a benzo[b]furan, benzo[b]thiophene, benzo[b]selenophene, or benzo[b]tellurophene group in the benzoaryl-pyridine ligand. Using X-ray crystallography, the chemical structures o
- Wang, Dezhi,Chen, Xi,Yang, Hua,Zhong, Daokun,Liu, Boao,Yang, Xiaolong,Yue, Ling,Zhou, Guijiang,Ma, Miaofeng,Wu, Zhaoxin
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supporting information
p. 15633 - 15645
(2020/11/24)
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- BTK Inhibitors and uses thereof
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The invention discloses a bruton's tyrosine kinase (BTK) inhibitor and use thereof. Specifically, the invention provides heteroaromatic compounds or stereoisomers, geometrical isomers, tautomers, racemates, nitrogen oxides, hydrates, solvates, metabolites and pharmaceutically acceptable salts or prodrugs thereof, and pharmaceutical compositions containing the heteroaromatic compounds; the invention also discloses use of the heteroaromatic compounds or the pharmaceutical compositions containing the heteroaromatic compounds in preparation of medicines; the medicines can be used for treating autoimmune diseases, inflammatory diseases or proliferative diseases.
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Paragraph 1600; 1606-1608
(2020/05/02)
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- Design and characterization of a heterocyclic electrophilic fragment library for the discovery of cysteine-targeted covalent inhibitors
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A fragment library of electrophilic small heterocycles was characterized through cysteine-reactivity and aqueous stability tests that suggested their potential as covalent warheads. The analysis of theoretical and experimental descriptors revealed correlations between the electronic properties of the heterocyclic cores and their reactivity against GSH that are helpful in identifying suitable fragments for cysteines with specific nucleophilicity. The most important advantage of these fragments is that they show only minimal structural differences from non-electrophilic counterparts. Therefore, they could be used effectively in the design of targeted covalent inhibitors with minimal influence on key non-covalent interactions.
- Keeley,ábrányi-Balogh,Keseru
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supporting information
p. 263 - 267
(2019/03/05)
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- Synthesis and structural studies of 1,4-di(2-pyridyl)-1,2,3-triazole dpt and its transition metal complexes; A versatile and subtly unsymmetric ligand
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The synthesis of the 'click' derived 1,4-di(2-pyridyl)-1,2,3-triazole (dpt) chelator/ligand from 2-azidopyridine and 2-ethynylpyridine using Cu(i) and TBTA by microwave assisted synthesis is presented. The complexes of the subtly unsymmetric dpt ligand with Cu(i), Pt(ii), Co(ii), and Ag(i) were structurally characterised by using conventional methods, as well as using single crystal and powder diffraction analysis. The results of the studies showed formation of discrete molecules displaying preferential binding of the d-metal cations through the pyridyl nitrogen N1 and the proximal triazolyl nitrogen N2 i.e. the 2-(1H-1,2,3-triazol-4-yl)pyridine or 'regular' chelate moiety despite the presence of a second potential binding pocket i.e. the 2-(1H-1,2,3-triazol-1-yl)pyridine chelate or 'inverse' moiety. This binding selectivity was corroborated through the study of the self-assembly of dpt with Cu(i) and Ag(i) using 1H NMR titration in CD3CN solution, as well as using UV-Vis absorption titrations; the former showing a broadening of the proton peaks associated with that chelate pocket.
- McCarney, Eoin P.,Hawes, Chris S.,Blasco, Salvador,Gunnlaugsson, Thorfinnur
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supporting information
p. 10209 - 10221
(2016/07/06)
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- A dramatic enhancing effect of InBr3 towards the oxidative Sonogashira cross-coupling reaction of 2-ethynylanilines
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The addition of InBr3 to the oxidative Sonogashira cross-coupling reaction of 2-ethynylaniline with (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane led to a dramatic increase in the reactivity to afford the corresponding 1,3-enynes bearing a trifluoromethyl group on their terminal sp2 carbon. The subsequent cyclization of these 1,3-enynes under palladium catalysis provides access to the corresponding indoles bearing a 3,3,3-trifluoroprop-1-enyl group at their 2-position.
- Ikeda,Omote,Kusumoto,Komori,Tarui,Sato,Ando
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supporting information
p. 2127 - 2133
(2016/02/18)
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- Metal cation binding to acetylenic tetrathiafulvalene–pyridine conjugates: affinity tuned by preorganization and cavity size
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A series of three structurally related mono-, bidentate and macrocyclic TTF-pyridine hosts were prepared and titrated with several metal cations including Ag+and Pb2+and studied using NMR- and UV–vis spectroscopy and cyclic voltammetry. For Ag+, we found an eightfold increase in binding affinity between the bidentate and macrocyclic host and conversely, for Pb2+, a 100-fold drop. Density functional theory (DFT) calculations support the increased binding affinity for Ag+is due to an N?N distance for the uncomplexed macrocycle very much suited for binding of Ag+but being too small for Pb2+. The bidentate host, on the other hand, is of a suitable size for Pb2+.
- Broman, S?ren Lindb?k,Andersen, Cecilie Lindholm,Jevric, Martyn,Tortzen, Christian Gregers,Hammerich, Ole,Nielsen, Mogens Br?ndsted
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p. 5831 - 5842
(2016/09/07)
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- The Role of Substituent Effects in Tuning Metallophilic Interactions and Emission Energy of Bis-4-(2-pyridyl)-1,2,3-triazolatoplatinum(II) Complexes
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The photoluminescence spectra of a series of 5-substituted pyridyl-1,2,3-triazolato PtII homoleptic complexes show weak emission tunability (ranging from λ=397-408 nm) in dilute (10-6 M) ethanolic solutions at the monomer level and strong tunability in concentrated solutions (10-4 M) and thin films (ranging from λ=487-625 nm) from dimeric excited states (excimers). The results of density functional calculations (PBE0) attribute this "turn-on" sensitivity and intensity in the excimer to strong Pt-Pt metallophilic interactions and a change in the excited-state character from singlet metal-to-ligand charge transfer (1MLCT) to singlet metal-metal-to-ligand charge transfer (1MMLCT) emissions in agreement with lifetime measurements. Turn-on tunability: A series of bis-4-(2-pyridyl)-1,2,3-triazolatoplatinum(II) complexes display variable emission tunability. At low concentration, the emission can be tuned only slightly by changing the nature of the substituent but at higher concentrations tunability is enhanced. This "turn-on" sensitivity in the excimeric emission is attributed to strong Pt-Pt metallophilic interactions and a change in the excited-state character.
- Prabhath, M. R. Ranga,Romanova, Julia,Curry, Richard J.,Silva, S. Ravi P.,Jarowski, Peter D.
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supporting information
p. 7949 - 7953
(2015/06/30)
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- 3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine capped Pd(0) nanoparticles: A catalyst for copper-free Sonogashira coupling of aryl halides in aqueous medium
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3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) capped Pd(0) nanoparticles (TzPdNPs) as a catalyst in the Sonogashira coupling of aryl halides in aqueous medium with diminished homocoupling is reported. The methodology provides a facile route to obtain polyfunctional alkynes under ligand- and copper-free conditions. The procedure is also efficient for aryl chlorides.
- Das, Sudipto,Samanta, Suvendu,Ray, Shounak,Biswas, Papu
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p. 75263 - 75267
(2015/09/21)
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- MGLUR REGULATORS
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Provided herein are compounds of the formula I: (I), as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment or prevention of mGluR5 mediated disorders, such as acute and/or chronic neurological disorders, cognitive disorders and memory deficits, as well as acute and chronic pain.
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Page/Page column 35
(2014/09/03)
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- Palladium-catalyzed oxidative homocoupling reaction of terminal acetylenes using trans-bidentatable 1-(2-pyridylethynyl)-2-(2-thienylethynyl)benzene
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Palladium-catalyzed oxidative homocoupling of terminal acetylenes, in air, occurred in the presence of 1-(2-pyridylethynyl)-2-(2-thienylethynyl)benzene as ligand, affording the corresponding conjugated diynes.
- Atobe, Shingo,Sonoda, Motohiro,Suzuki, Yuki,Yamamoto, Takuya,Masuno, Haruna,Shinohara, Hiroyuki,Ogawa, Akiya
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p. 359 - 370
(2013/03/28)
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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)
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- Efficient synthesis of 2-pyridylenynes and application in cobalt-catalysed benzannulation reactions
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The cobalt-catalysed benzannulation of 2-pyridine-substituted enynes gave 2,3-bis(2-pyridyl)styrenes in moderate yields. The reaction with dibromomethane as well as diiodomethane generated the corresponding planar-chiral bispyridinium salts in good yields
- R?se, Philipp,Pünner, Florian,Hilt, Gerhard,Harms, Klaus
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p. 1101 - 1104
(2013/06/27)
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- NOVEL TRIAZOLE COMPOUNDS II
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The present invention is concerned with novel triazole compounds of formula (I) wherein A, X, Y, u, v, R1, R2, and R3 are as described herein, as well as pharmaceutically acceptable salts thereof. The compounds of present invention have affinity and selectivity for the GABA A α5 receptor. Further the present invention is concerned with the manufacture of the compounds of formula (I), pharmaceutical compositions comprising them and their use as pharmaceuticals.
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Page/Page column 15
(2012/05/20)
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- TRIAZOLE DERIVATIVES AS LIGANDS FOR GABA RECEPTORS
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The present invention is concerned with novel triazole compounds of formula (I) wherein A, X, Y, u,v, R1, R2, and R3 are as described herein, as well as pharmaceutically acceptable salts thereof. The active compounds of present invention have affinity and selectivity for the GABA A α5 receptor. Further the present invention is concerned with the manufacture of the compounds of formula (I), pharmaceutical compositions comprising them and their use as medicaments.
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Page/Page column 32
(2012/05/31)
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- NOVEL TRIAZOLE COMPOUNDS I
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The present invention is concerned with novel triazole compounds of formula (I) wherein A, X, Y, Z, R1, R2, and R3 are as described herein, as well as pharmaceutically acceptable salts and esters thereof. The active compounds of present invention have affinity and selectivity for the GABA A α5 receptor. Further the present invention is concerned with the manufacture of the compounds of formula (I), pharmaceutical compositions comprising them and their use as medicaments.
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Page/Page column 20
(2012/05/20)
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- TRIAZOLE DERIVATIVES AND THEIR USE FOR NEUROLOGICAL DISORDERS
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The present invention is concerned with novel triazole compounds of formula (I) wherein A, X, Y, Z, R1, R2, and R3 are as described herein, as well as pharmaceutically acceptable salts and esters thereof. The active compounds of present invention have affinity and selectivity for the GABA A α5 receptor. Further the present invention is concerned with the manufacture of the compounds of formula (I), pharmaceutical compositions comprising them and their use as medicaments.
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Page/Page column 45
(2012/05/31)
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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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- Synthesis of polydiacetylenes with pyridyl groups directly bound to the main chain
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N-Substituted carbamic acid esters of 8-pyridyl-5,7-octadiyn-1-ol were synthesized and all the monomers showed solid-state polymerizabilities by UV irradiation to give polydiacetylenes with pyridyl groups directly bound to the -conjugated backbone. Hydrogen-bond complexes of these monomers with dodecanoic acid (DA) or perfluorododecanoic acid (PFDA), in which the pyridyl nitrogen atom formed a hydrogen bond with the hydrogen atom of the carboxyl group, were also prepared. Although complex formability of DA with the monomers in this study was not so high, many PFDA complexes were obtained because of the higher acidity. All complexes could be polymerized in the solid state and the conversion increased by complexation compared with the original monomers. More favorable monomer stacking for solid-state polymerization could be achieved by combination of intermolecular hydrogen bonds between urethane groups and alkyl (or perfluoroalkyl) chain packing. Copyright
- Shibuya, Tadahiro,Tatewaki, Yoko,Okada, Shuji
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p. 93 - 97,5
(2020/09/02)
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- Copper-free sonogashira coupling reaction using a trans-spanning 1,2-Bis(2-thienylethynyl)benzene Ligand
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Novel copper-free Sonogashira coupling reaction of aryl halides with terminal acetylenes proceeded in the presence of 1,2-bis(2-thienylethynyl) benzene (1) as a trans-bidentatable ligand.
- Atobe, Shingo,Sonoda, Motohiro,Suzuki, Yuki,Shinohara, Hiroyuki,Yamamoto, Takuya,Ogawa, Akiya
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p. 925 - 927
(2011/12/05)
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- One-pot procedure for the synthesis of unsymmetrical diarylalkynes
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Unsymmetrical diarylalkynes are accessible by a one-pot procedure from two different aryl halides and (trimethylsilyl)acetylene. The three-component coupling is initialized by a Pd/Cu-catalyzed Sonogashira coupling of an aryl halide with (trimethylsilyl)a
- Severin, Rene,Reimer, Jessica,Doye, Sven
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supporting information; experimental part
p. 3518 - 3521
(2010/07/17)
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- High-efficiency solution processable electrophosphorescent iridium complexes bearing polyphenylphenyl dendron ligands
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We report the synthesis and electrophosphorescent behavior of a series of novel iridium complex materials (Complexes A-F), which are composed of ligands bearing polyphenylphenyl dendron groups and acetylacetonate. Yellow to saturated red organic light-emitting diodes (OLEDs) based on these newly developed Ir complexes were fabricated through solution process by doping the complex materials into polyvinyl carbazole (PVK)/2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) matrices. The emission wavelengths of the materials could be effectively tuned from 549 nm to 640 nm by changing the conjugation of the ligands either through incorporating additional aromatic segment (e.g. phenyl or fluorenyl group) onto the basic dendron ligand or fusing two of the phenyl rings on the polyphenylphenyl dendron group. High performance devices with the configuration of ITO/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) (50 nm)/PVK:PBD (40%):Ir complex (6%) (70 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (12 nm)/Alq3 (20 nm)/Mg:Ag (150 nm) have been demonstrated. For example, when Complex B was used as the emissive layer, maximum current efficiency of 34.0 cd/A and external quantum efficiency of 10.3% have been achieved. When 1,3,5-tris(N-phenylbenzimidazol-2-yl) benzene (TPBI) was used as the block layer, the efficiencies can be further improved to 46.3 cd/A and 13.9%, respectively. These solution processed OLED devices demonstrated quite stable EL efficiencies over a large range of current density, which indicated that triplet-triplet annihilation in electrophosphorescence could be effectively suppressed by incorporation of the polyphenylphenyl dendron structure into iridium complexes.
- Huang, Chun,Zhen, Chang-Gua,Su, Siew Ping,Chen, Zhi-Kuan,Liu, Xiao,Zou, De-Chun,Shi, Yan-Rong,Loh, Kian Ping
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experimental part
p. 1317 - 1324
(2009/09/06)
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- Thieme Chemistry Journal Awardees - Where are they now? A general one-step synthesis of alkynes from enolisable carbonyl compounds
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Terminal and internal acetylenes were obtained in good to excellent isolated yields from carbonyl compounds by converting the carbonyl functionality into the enol nonaflate intermediate followed by elimination to give the C-C triple bond. The one-pot transformations were uniformly induced by phosphazene bases combined with mildly electrophilic nonafluorobutane-1-sulfonyl fluoride. The method is the most general among those reported to date as it applies to both acyclic ketones and aldehydes. Only moderate kinetic regioselectivity in favour of alk-1-yne achieved from methyl n-alkyl ketone represents a limitation of the method. In all the other instances, individual acetylenic products were obtained. Georg Thieme Verlag Stuttgart.
- Lyapkalo, Ilya M.,Vogel, Michael A. K.,Boltukhina, Ekaterina V.,Vav?ík, Ji?í
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scheme or table
p. 558 - 561
(2009/07/09)
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- 1,3-Dipolar cycloaddition of alkynes to azides. Construction of operationally functional metal responsive fluorophores
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The copper catalyzed 1,3-dipolar cycloaddition of 4-butoxyphenylazide with 2-, 3- or 4-ethynylpyridine furnishes 1,4-diaryltriazoles, which display turn-on fluorescence upon addition of metal cations. The Royal Society of Chemistry.
- Schweinfurth, David,Hardcastle, Kenneth I.,Bunz, Uwe H. F.
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p. 2203 - 2205
(2008/12/23)
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- Terminal alkynes from aldehydes via dehydrohalogenation of (Z)-1-iodo-1-alkenes with TBAF
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Terminal alkynes were prepared in near quantitative yields via dehydrohalogenation of (Z)-1-iodo-1-alkenes with tetrabutylammonium fluoride (TBAF) under mild conditions. The methodology was expanded to include a one-pot, direct synthesis of terminal alkynes from aldehydes without the necessity of isolating and purifying the intermediate iodoalkene.
- Beshai, Mira,Dhudshia, Bhartesh,Mills, Ryan,Thadani, Avinash N.
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supporting information; experimental part
p. 6794 - 6796
(2009/04/07)
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- Blue fluorescent 4a-aza-4b-boraphenanthrenes
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Figure presented Phenanthrene analogues with internalized B-N moieties were found to afford blue light emission with good quantum efficiencies, whereas the isomeric species with peripheral B-N moieties displayed only UV emission behavior, like the all-carbon framework.
- Bosdet, Michael J. D.,Jaska, Cory A.,Piers, Warren E.,Sorensen, Ted S.,Parvez, Masood
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p. 1395 - 1398
(2007/12/31)
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- Double elimination protocol for the synthesis of arylene ethynylenes containing heteroaromatic rings
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The double elimination reaction of β-substituted sulfones offers a versatile strategy for synthesis of arylene ethynylene kits containing heteroaromatic rings. A sequence of aldol reaction between α-sulfonyl carbanion and aldehyde, trapping the resulting aldolate to give β-substituted sulfone, and double elimination of this intermediate can be integrated in one pot. This protocol allows thiophene, pyridine, and ferrocene units to be accommodated in phenylene ethynylene arrays.
- Orita, Akihiro,Ye, Fangguo,Babu, Govindarajulu,Ikemoto, Tomohiro,Otera, Junzo
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p. 716 - 727
(2007/10/03)
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- Efficient synthesis of a complete donor/acceptor bis(aryl)diyne family
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A facile route to a family of bis(aryl)diynes containing both an electron donating pyridine ring and an electron accepting iodobenzene has been developed. The convergent synthesis involves the coupling of 2-, 3-, or 4-bromopyridine with TMS-acetylene, followed by deprotection to form the first half of the molecule. Similarly, 2-, 3-, or 4-iodoaniline was coupled to TMS-acetylene after protection of the amine group as a diethyltriazine. After conversion of the triazine to an iodine, deprotection of the acetylene and formation of the corresponding bromophenyl-acetylene, the two halves of the molecule were coupled under Cadiot-Chodkiewicz conditions. Nine new compounds were prepared, each of which was found to thermally polymerize from the melt. None of the compounds underwent photochemical polymerization in the solid-state.
- Holmes, Brian T.,Pennington, William T.,Hanks, Timothy W.
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p. 2447 - 2461
(2007/10/03)
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- Microwave-assisted in situ deprotection and ω-methoxylation of TMS-protected aryl alkynes
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Using microwave technology, rapid ω-methoxylation of aryl alkynes is possible.
- Wettergren, Jenny,Minidis, Alexander B. E.
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p. 7611 - 7612
(2007/10/03)
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- Synthesis of diterpenoid indole derivatives via tethered chromium alkynylaminocarbenes
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Thermolysis of podocarpane-tethered chromiumalkynylaminocarbenes gives indole derivatives in moderate yields. (Arylalkynyl)aminocarbenes could not be isolated. Ester derivatives were formed due to trapping of the intermediate ketene in situ with butan-1-o
- Woodgate, Paul D.,Sutherland, Hamish S.
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p. 131 - 144
(2007/10/03)
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- Synthesis and preliminary testing of molecular wires and devices
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Presented here are several convergent synthetic routes to conjugated oligo(phenylene ethynylene)s. Some of these oligomers are free of functional groups, while others possess donor groups, acceptor groups, porphyrin interiors, and other heterocyclic interiors for various potential transmission and digital device applications. The syntheses of oligo(phenylene ethynylene)s with a variety of end groups for attachment to numerous metal probes and surfaces are presented. Some of the functionalized molecular systems showed linear, wire-like, current versus voltage (I(V)) responses, while others exhibited nonlinear I(V) curves for negative differential resistance (NDR) and molecular random access memory effects. Finally, the syntheses of functionalized oligomers are described that can form self-assembled monolayers on metallic electrodes that reduce the Schottky barriers. Information from the Schottky barrier studies can provide useful insight into molecular alligator clip optimizations for molecuar electronics.
- Tour, James M.,Rawlett, Adam M.,Kozaki, Masatoshi,Yao, Yuxing,Jagessar, Raymond C.,Dirk, Shawn M.,Price, David W.,Reed, Mark A.,Zhou, Chong-Wu,Chen, Jia,Wang, Wenyong,Campbell, Ian
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p. 5118 - 5134
(2007/10/03)
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- Orbital interactions in ethynylpyridines
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He I and He II photoelectron spectra of several isomeric ethynyl- and diethynylpyridines have been measured. The spectra were analyzed with the aid of empirical arguments: relative band intensities and comparison with spectra of related compounds (ethynyl
- Ng, Siu Choon,Novak, Igor,You, Xiaomei,Huang, Wei
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p. 904 - 908
(2007/10/03)
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- Synthesis and alkylation of pyridylacetylenes under phase transfer catalysis conditions in a liquid/solid system
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We have investigated the alkylation of 2-methyl-5-ethynylpyridine by butyl bromide in liquid/liquid and liquid/solid two-phase catalytic systems. We have shown that the catalytic system solid KOH/18-crown-6/CuBr/toluene is the most active in this reaction; using this system, we obtained alkylation products of ethynylpyridines in 34-43% yields. 1998 Plenum Publishing Corporation.
- Abele,Abele,Ruhina,Gaukhman,Lukevics
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p. 459 - 462
(2007/10/03)
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- Synthesis of 1,4-di(n-pyridyl)buta-1,3-diyne and formation of charge-transfer complexes. X-Ray structure of 1,4-di(3-pyridyl)buta-1,3-diyne
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Ethynylpyridines have been satisfactorily prepared by two different routes: (a) the Wittig reaction between chloromethylene(triphenyl)phosphine ylide and a pyridinecarbaldehyde, followed by elimination of hydrogen chloride; (b) from the 2-methyl-4-(n-pyridyl)but-3-yn-2-ol intermediate, by elimination of acetone. 1,4-Di(n-pyridyl)buta-1,3-diynes are obtained by oxidative dimerization in good yield. An X-ray structure of the 3-substituted dimer is reported. Mono- and di-methyl salts of the 3-substituted diyne have been obtained and the charge-transfer complexes with tetramethyl-p-phenylenediamine (TMPD) are formed.
- Rodriguez, J. Gonzalo,Martin-Villamil, Rosa,Cano, Felix H.,Fonseca, Isabel
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p. 709 - 714
(2007/10/03)
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- Direct synthesis of heteroarylethynes via palladiumcatalyzed coupling of heteroaryl halides with ethynylzinc halides. Its application to an efficient synthesis of a thiophenelactone from chamaemelum nobile
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A variety of terminal alkynes containing a heteroaryl group can be directly and selectively synthesized by the Pd-catalyzed coupling of heteroaryl iodides or bromides with ethynylzinc halides. Various compounds of this class containing furan, thiophene, and pyridine have been prepared, and the procedure has been applied to an efficient and selective synthesis of a thiophenelactone from Chamaemelum nobile L.
- Negishi, Ei-Ichi,Xu, Caiding,Tan, Ze,Kotora, Martin
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p. 209 - 214
(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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- Ethynylation of aryl halides by a modified Suzuki reaction: Application to the syntheses of combretastatin A-4, A-5 and lunularic acid
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On treatment with trimethyl borate sodium acetylide undergoes a palladium-catalyzed cross coupling with functionalized aryl halides or triflates in reasonable to good yields. The ethynylarenes thus obtained serve as building blocks for the formation of the highly effective tubulin polymerization inhibitors combretastatin A-4 (1) and A-5 (2) as well as for the synthesis of the plant-growth regulator lunularic acid (36). VCH Verlagsgesellschaft mbH, 1996.
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