- UREA, AMIDE, AND SUBSTITUTED HETEROARYL COMPOUNDS FOR CBL-B INHIBITION
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Compounds of formulae (I) and (II), compositions, and methods for use in inhibiting the E3 enzyme Cbl-b in the ubiquitin proteasome pathway are disclosed. The compounds, compositions, and methods can be used to modulate the immune system, to treat diseases amenable to immune system modulation, and for treatment of cells invivo, in vitro, or ex vivo.
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Paragraph 0539
(2021/02/05)
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- Iodonium Cation-Pool Electrolysis for the Three-Component Synthesis of 1,3-Oxazoles
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The synthesis of 1,3-oxazoles from symmetrical and unsymmetrical alkynes was realized by an iodonium cation-pool electrolysis of I2 in acetonitrile with a well-defined water content. Mechanistic investigations suggest that the alkyne reacts with the acetonitrile-stabilized I+ ions, followed by a Ritter-type reaction of the solvent to a nitrilium ion, which is then attacked by water. The ring closure to the 1,3-oxazoles released molecular iodine, which was visible by the naked eye. Also, some unsymmetrical internal alkynes were tested and a regioselective formation of a single isomer was determined by two-dimensional NMR experiments.
- Sattler, Lars E.,Hilt, Gerhard
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supporting information
p. 605 - 608
(2020/12/07)
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- Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
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Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
- Luo, Xiaosheng,Wang, Ping
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supporting information
p. 4960 - 4965
(2021/07/20)
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- Cobalt-Catalyzed Hydroalkynylation of Vinylaziridines
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Transition metal-catalyzed hydroalkynylation reactions are efficient transformations allowing the straightforward formation of functionalized alkynes. Therein, we disclose the cobalt-catalyzed hydroalkynylation of vinylaziridines giving rise to both linea
- Biletskyi, Bohdan,Kong, Lingyu,Tenaglia, Alphonse,Clavier, Hervé
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supporting information
p. 2578 - 2585
(2021/03/18)
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- Au(I) Catalyzed Synthesis of Densely Substituted Pyrazolines and Dihydropyridines via Sequential Aza-Enyne Metathesis/6π-Electrocyclization
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A gold(I) autotandem catalysis protocol is reported for the de novo synthesis of densely substituted pyrazolines and dihydropyridines from the corresponding imine derivatives in a highly regioselective fashion via a one-pot aza-enyne metathesis/6π-electrocyclization sequence. The substituents on the nitrogen atom of the imine perfectly control the reaction pathways from the pivotal 1-azabutadiene intermediate; thus, carbazates were converted into pyrazolines via 6π-electrocyclization of α,β-unsaturated hydrazones, while aryl imines provided dihydropyridines via 6π-electrocyclization of 3-azahexatrienes.
- Sugimoto, Kenji,Kosuge, Shuto,Sugita, Takae,Miura, Yuka,Tsuge, Kiyoshi,Matsuya, Yuji
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supporting information
p. 3981 - 3985
(2021/05/26)
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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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- Catalytic Decarboxylation of Silyl Alkynoates to Alkynylsilanes
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Herein, we describe a decarboxylative approach to the preparation of alkynylsilanes. Treatment of a silyl alkynoate in N,N-dimethylformamide (DMF) at 80 °C in the presence of catalytic amounts of CuCl and PCy3 produced the corresponding alkynylsilane in excellent yield. The copper-catalyzed decarboxylation proceeded smoothly with low catalyst loadings (0.5 mol % of CuCl and 1.0 mol % of PCy3) under mild reaction conditions and is easily scalable to gram quantities.
- Aoyagi, Keiya,Choi, Jun-Chul,Kawatsu, Takahiro,Matsumoto, Kazuhiro,Nakajima, Yumiko,Sato, Kazuhiko
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supporting information
(2020/09/15)
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- Copper-Catalyzed Ring Opening of [1.1.1]Propellane with Alkynes: Synthesis of Exocyclic Allenic Cyclobutanes
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Despite the long history and interesting properties of propellanes, these compounds still have tremendous potential to be exploited in synthetic organic chemistry. Herein we disclose an experimentally simple procedure to achieve cyclobutane-containing allenes and alkynes through a copper-catalyzed ring opening of [1.1.1]propellane and subsequent reaction with ethynes.
- Lasányi, Dániel,Tolnai, Gergely L.
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supporting information
p. 10057 - 10062
(2019/12/24)
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- p-TSA-Based DESs as “Active Green Solvents” for Microwave Enhanced Cyclization of 2-Alkynyl-(hetero)-arylcarboxylates: an Alternative Access to 6-Substituted 3,4-Fused 2-Pyranones
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In this paper, we describe the use of p-TSA based Deep Eutectic Solvents (DESs) as alternative environmental-friendly “active” solvents for the microwave-mediated synthesis of 6-substituted 3,4-fused 2-pyranones, and in particular isocoumarins, starting from 2-alkynyl-(hetero)arylcarboxylates. When the alkyne terminus bears a neutral or an electron-donating group (EDG), the reactions are fast, clean and highly regioselective, to give the 6-endo-dig cyclization products in good to excellent yields. For substrates bearing an electron-withdrawing group (EWG) on the alkyne end, the regioselectivity can be tuned by adding a small amount of silver(I) triflate as co-catalyst. DES was demonstrated to be reusable without loss of efficiency in terms of reaction yields. Based on experimental evidence and previous findings, two competitive mechanisms working simultaneously are proposed to explain the outcomes and the regioselectivity issues.
- Curti, Fabiola,Tiecco, Matteo,Pirovano, Valentina,Germani, Raimondo,Caselli, Alessandro,Rossi, Elisabetta,Abbiati, Giorgio
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p. 1904 - 1914
(2019/02/26)
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- Et2Zn-mediated stoichiometric C(sp)-H silylation of 1-alkynes and chlorosilanes
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A first example of an Et2Zn mediated silylation of 1-aklynes is reported. A series of functional groups are tolerated in this reaction. Mechanistic studies support Zn alkynilides as intermediates in the reaction. This reaction protocol provides a practical method for the preparation of alkynylsilanes and expands the application of organometallic zinc in organic synthesis.
- Huang, Pan,Xu, Dawen,Reich, Robert M.,Kaiser, Felix,Liu, Boping,Kühn, Fritz E.
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supporting information
p. 1574 - 1577
(2019/05/17)
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- Trimethylsilyl-Protected Alkynes as Selective Cross-Coupling Partners in Titanium-Catalyzed [2+2+1] Pyrrole Synthesis
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Trimethylsilyl (TMS)-protected alkynes served as selective alkyne cross-coupling partners in titanium-catalyzed [2+2+1] pyrrole synthesis. Reactions of TMS-protected alkynes with internal alkynes and azobenzene under the catalysis of titanium imido comple
- Chiu, Hsin-Chun,Tonks, Ian A.
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supporting information
p. 6090 - 6094
(2018/05/30)
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- Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles
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For the synthesis of unsymmetrical acetylenes, a Sonogashira coupling-deprotection-Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic acid, an inexpensive nontoxic compound, was used to promote the selective desilylation. This method enables the efficient synthesis of unsymmetric acetylenes with other silylated functional groups present. Further possibilities of the method were explored by synthesis of heterocycles.
- Lasányi, Dániel,Mészáros, ádám,Novák, Zoltán,Tolnai, Gergely L.
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p. 8281 - 8291
(2018/06/11)
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- Palladium catalysed regio- and stereoselective synthesis of (E)-4-aryl-1,3-bis(trimethylsilyl)but-3-en-1-ynes
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A practical and general synthetic approach to a series of 4-aryl-but-3-en-1-ynes is described. In the presence of palladium complexes a variety of aryl bromides (or iodides) undergo coupling with two equivalents of trimethylsilylacetylene with the formati
- Rogalski, Szymon,Kubicki, Maciej,Pietraszuk, Cezary
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p. 6192 - 6198
(2018/09/17)
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- A phosphine-free, atom-efficient cross-coupling of aryl iodides with triarylindiums or trialkynylindiums catalyzed by immobilization of palladium(0) in MCM-41
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The first phosphine-free heterogeneous atom-efficient cross-coupling reaction of aryl iodides with triarylindiums or trialkynylindiums was achieved in THF at 68 °C by using 1 mol% of MCM-41-immobilized palladium(0)-Schiff base complex [MCM-41-N,N-Pd(0)] as catalyst, yielding a variety of unsymmetrical biaryls and arylalkynes in good to excellent yields. The heterogeneous palladium(0) catalyst could easily be prepared via a simple procedure from commercially readily available reagents, and recovered by filtration of the reaction solution and recycled at least 10 times without significant loss of activity.
- Lei, Zhiwei,Liu, Haiyi,Cai, Mingzhong
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- A highly efficient and recyclable Pd(PPh3)4/PEG-400 system for Stille cross-coupling reactions of organostannanes with aryl bromides
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Pd(PPh3)4 in PEG-400 is shown to be a highly efficient catalyst for the Stille cross-coupling reactions of various organotin compounds with aryl bromides. The reaction could be conducted at 80 °C using NaOAc as base, yielding a variety of biaryls, alkynes and alkenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether and the Pd(PPh3)4/PEG-400 system could be easily recycled and reused five times without any significant loss of activity.
- Huang, Xue,Yao, Fang,Wei, Ting,Cai, Mingzhong
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p. 547 - 550
(2017/10/03)
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- Microwave-assisted copper- and palladium-catalyzed sonogashira-type coupling of aryl bromides and iodides with trimethylsilylacetylene
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An efficient and rapid method was developed for the synthesis of 1-aryl-2-(trimethylsilyl)acetylene. Copper and palladium-catalyzed sonogashira-type coupling of trimethylsilylacetylene and aryl bromides or iodides in the presence of triethylamine as base
- Lei, Yonghua,Hu, Tianhan,Wu, Xingsen,Wu, Yue,Xiang, Hua,Sun, Haopeng,You, Qidong,Zhang, Xiaojin
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p. 1100 - 1103
(2016/03/09)
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- Structure-based design, synthesis and evaluation in vitro of arylnaphthyridinones, arylpyridopyrimidinones and their tetrahydro derivatives as inhibitors of the tankyrases
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Abstract The tankyrases are members of the PARP superfamily; they poly(ADP-ribosyl)ate their target proteins using NAD+ as a source of electrophilic ADP-ribosyl units. The three principal protein substrates of the tankyrases (TRF1, NuMA and axin) are involved in replication of cancer cells; thus inhibitors of the tankyrases may have anticancer activity. Using structure-based drug design and by analogy with known 3-arylisoquinolin-1-one and 2-arylquinazolin-4-one inhibitors, series of arylnaphthyridinones, arylpyridinopyrimidinones and their tetrahydro-derivatives were synthesised and evaluated in vitro. 7-Aryl-1,6-naphthyridin-5-ones, 3-aryl-2,6-naphthyridin-1-ones and 3-aryl-2,7-naphthyridin-1-ones were prepared by acid-catalysed cyclisation of the corresponding arylethynylpyridinenitriles or reaction of bromopyridinecarboxylic acids with β-diketones, followed by treatment with NH3. The 7-aryl-1,6-naphthyridin-5-ones were methylated at 1-N and reduced to 7-aryl-1-methyl-1,2,3,4-tetrahydro-1,6-naphthyridin-5-ones. Cu-catalysed reaction of benzamidines with bromopyridinecarboxylic acids furnished 2-arylpyrido[2,3-d]pyrimidin-4-ones. Condensation of benzamidines with methyl 1-benzyl-4-oxopiperidine-3-carboxylate and deprotection gave 2-aryl-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-4-ones, aza analogues of the known inhibitor XAV939. Introduction of the ring-N in the arylnaphthyridinones and the arylpyridopyrimidinones caused >1000-fold loss in activity, compared with their carbocyclic isoquinolinone and quinazolinone analogues. However, the 7-aryl-1-methyl-1,2,3,4-tetrahydro-1,6-naphthyridin-5-ones showed excellent inhibition of the tankyrases, with some examples having IC50 = 2 nM. One compound (7-(4-bromophenyl)-1-methyl-1,2,3,4-tetrahydro-1,6-naphthyridin-5-one) showed 70-fold selectivity for inhibition of tankyrase-2 versus tankyrase-1. The mode of binding was explored through crystal structures of inhibitors in complex with tankyrase-2.
- Kumpan, Katerina,Nathubhai, Amit,Zhang, Chenlu,Wood, Pauline J.,Lloyd, Matthew D.,Thompson, Andrew S.,Haikarainen, Teemu,Lehti?, Lari,Threadgill, Michael D.
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supporting information
p. 3013 - 3032
(2015/08/03)
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- Rh(III)-catalyzed cyclization reaction of azoles with alkynes: Efficient synthesis of azole-fused-pyridines
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A Rh(III)-catalyzed cyclization of azoles with alkynes has been developed. A variety of azole-fused-pyridines were obtained in good to excellent yields and regioselectivity. Both the C5 and the C4 position of azoles were suitable for the reaction.
- Chen, Xuebing,Wu, Youzhi,Xu, Jinyi,Yao, Hequan,Lin, Aijun,Huang, Yue
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supporting information
p. 9186 - 9189
(2015/09/07)
-
- Visible-light-induced chemoselective deboronative alkynylation under biomolecule-compatible conditions
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Here, we report a visible-light-induced deboronative alkynylation reaction, which is redox-neutral and works with primary, secondary and tertiary alkyl trifluoroborates or boronic acids to generate aryl, alkyl and silyl substituted alkynes. This reaction is highly chemoselective and performs well on substrates containing alkenes, alkynes, aldehydes, ketones, esters, nitriles, azides, aryl halides, alkyl halides, alcohols, and indoles, with no detectable occurrence of side reactions. The mechanism of this novel C(sp3)-C(sp) bond coupling reaction was investigated by luminescence quenching, radical trapping, on-off light, and 13C-isotopic-labeling experiments. This reaction can be performed in neutral aqueous conditions, and it is compatible with amino acids, nucleosides, oligosaccharides, nucleic acids, proteins, and cell lysates.
- Huang, Hanchu,Zhang, Guojin,Gong, Li,Zhang, Shuaiyan,Chen, Yiyun
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supporting information
p. 2280 - 2283
(2014/03/21)
-
- Halogen bonding of (iodoethynyl)benzene derivatives in solution
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Halogen bonding (XB) between (iodoethynyl)benzene donors and quinuclidine in benzene affords binding free enthalpies (δG, 298 K) between -1.1 and -2.4 kcal mol-1, with a strong LFER with the Hammett parameter σpara. The enthalpic dri
- Dumele, Oliver,Wu, Dino,Trapp, Nils,Goroff, Nancy,Diederich, Francois
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supporting information
p. 4722 - 4725
(2015/04/27)
-
- 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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- Regio- and stereoselective dimerization of arylacetylenes and optical and electrochemical studies of (E)-1,3-enynes
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The N-heterocyclic carbene palladium complex (SIPr)Pd(cinnamyl)Cl [SIPr=N,N'-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) promotes regio- and stereospecific dimerization of a variety of arylalkynes to give (E)-1,3-enynes in good to excellent yields. An efficient and practical procedure for their synthesis was developed using a biphasic aqueous alkali/heptane system. Optical and electronic properties of (E)-1,3-enynes are highly tunable. Depending on the nature of the substituents, HOMO energies vary in the range 5.3-6.0eV. (E)-1,3-Enynes can exhibit intense photoluminescence in the spectral region 350-500nm.
- Morozov, Oleg S.,Asachenko, Andrey F.,Antonov, Denis V.,Kochurov, Vitaly S.,Paraschuk, Dmitry Yu.,Nechaev, Mikhail S.
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supporting information
p. 2671 - 2678
(2014/09/29)
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- Copper-catalyzed monoborylation of silylalkynes; Regio- and stereoselective synthesis of (Z)-β-(borylvinyl)silanes
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The selective copper-catalyzed borylation of silylalkynes in the presence of a diboron reagent and methanol produced a variety of (Z)-β-(borylvinyl) silanes. The appropriate use of a selective ligand for copper allows the chemo-, regio-, and stereoselective monoborylation of silylalkynes. The β-regioselectivity of an N-heterocyclic carbene (NHC)-copper catalyst was investigated by DFT calculations.
- Chae, Yeong Mi,Bae, Jun Sung,Moon, Jong Hun,Lee, Jin Yong,Yun, Jaesook
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supporting information
p. 843 - 849
(2014/04/03)
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- Formal anti-markovnikov hydroamination of terminal aryl alkynes with pinacolborane and hydroxylamines via Zr/Cu sequential catalysis
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We have explored a novel dry plasma process for the fabrication of electrodes on Nafion surfaces. Nanosized pillar structures were prepared through argon ion (Ar+) plasma treatment. The shear strengths of Au electrodes on plasma-treated Nafion surfaces were investigated. We found that the maximum shear strength (1.08 MPa) of Au-Nafion was observed under the optimal conditions (8 min, 100 W, 5 Pa, Ar+). Finally, we successfully prepared strongly bonded Au electrodes on Nafion through plasma surface treatment without using a wet plating process.
- Sakae, Ryosuke,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 1128 - 1130
(2013/10/22)
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- General and selective head-to-head dimerization of terminal alkynes proceeding via hydropalladation pathway
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A general highly regio- and stereoselective palladium-catalyzed head-to-head dimerization reaction of terminal acetylenes is presented. This methodology allows for the efficient synthesis of a variety of 1,4-enynes as single E stereoisomers. Computational studies reveal that this dimerization reaction proceeds via the hydropalladation pathway.
- Jahier, Claire,Zatolochnaya, Olga V.,Zvyagintsev, Nickolay V.,Ananikov, Valentine P.,Gevorgyan, Vladimir
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supporting information; experimental part
p. 2846 - 2849
(2012/07/17)
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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)
-
- Regioselective solvent-dependent benzannulation of conjugated enynes
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The transformation of enynes under cobalt-catalysis leads to symmetrical benzannulation products in dichloromethane. In tetrahydrofuran the cobalt-catalysed reactions afforded the unprecedented unsymmetrical benzannulation products in moderate to good yields and good regioselectivities. In addition, cyclotrimerisation of the alkyne subunit can be realised when electron-deficient enynes are applied in the cobalt-catalysed transformations to generate 1,2,4-trivinylbenzene derivatives using tetrahydrofuran as solvent.
- Puenner, Florian,Hilt, Gerhard
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supporting information; experimental part
p. 3617 - 3619
(2012/05/20)
-
- Stereodivergent zinc-mediated three-component synthesis of tri- and tetrasubstituted alkenes
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Zinc simple: The loading-dependent zinc-mediated addition of benzyl bromides to alkynes is the key step for the formation of vinyl bromides. In combination with a palladium-catalyzed Suzuki cross-coupling reaction with boronic acids, tri- and tetrasubstit
- Miersch, Anne,Hilt, Gerhard
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supporting information; experimental part
p. 9798 - 9801
(2012/09/07)
-
- Functionalisation of heteroaromatic N-oxides using organic superbase catalyst
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Functionalisation of quinoline N-oxide was investigated using phophazene base as a catalyst; alkynylation and heteroarylation at 2-position were successfully achieved via nucleophilic addition-elimination process.
- Araki, Yuta,Kobayashi, Koji,Yonemoto, Misato,Kondo, Yoshinori
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supporting information; experimental part
p. 78 - 80
(2011/02/23)
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- Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira-Glaser cyclization sequence
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Based upon a consecutive one-pot Sonogashira-Glaser coupling-cyclization sequence a variety of 2,5-di(hetero)arylthiophenes were synthesized in moderate to good yields. A single Pd/Cu-catalyst system, without further catalyst addition, and easily available, stable starting materials were used, resulting in a concise and highly efficient route for the synthesis of the title compounds. This novel pseudo five-component synthesis starting from iodo(hetero)arenes is particularly suitable as a direct access to well-defined thiophene oligomers, which are of peculiar interest in materials science.
- Urselmann, Dominik,Antovic, Dragutin,Mueller, Thomas J. J.
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supporting information; experimental part
p. 1499 - 1503
(2011/12/22)
-
- Solvent-induced selectivity switching: Intermolecular allylsilylation, arylsilylation, and silylation of alkynes over montmorillonite catalyst
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Proton-exchanged montmorillonite showed catalytic activity for intermolecular allylsilylation, arylsilylation, and terminal silylation of alkynes with allylsilanes. The reaction selectivity greatly depended on the solvent used. Reactions proceeded with va
- Motokura, Ken,Matsunaga, Shigekazu,Miyaji, Akimitsu,Yashima, Tatsuaki,Baba, Toshihide
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experimental part
p. 6687 - 6692
(2012/01/03)
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- Synthesis and antiplasmodial activity of new indolone N-Oxide derivatives
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A series of 66 new indolone-N-oxide derivatives was synthesized with three different methods. Compounds were evaluated for in vitro activity against CQ-sensitive (3D7), CQ-resistant (FcB1), and CQ and pyrimethamine cross-resistant (K1) strains of Plasmodium falciparum (P.f.), aswell as for cytotoxic concentration (CC50) on MCF7 and KB human tumor cell lines. Compound 26 (5-methoxy-indolone-N-oxide analogue) had the most potent antiplasmodial activity in vitro (50 MCF7/IC50 FcB1: 14623; CC50 KB/IC50 3D7: 198823). In in vivo experiments, compound 1 (dioxymethylene derivatives of the indolone-N-oxide) showed the best antiplasmodial activity against Plasmodium berghei, 62% inhibition of the parasitaemia at 30 mg/kg/day. 2009 American Chemical Society.
- Nepveu, Fran?oise,Kim, Sothea,Boyer, Jeremie,Chatriant, Olivier,Ibrahim, Hany,Reybier, Karine,Monje, Marie-Carmen,Chevalley, Severine,Perio, Pierre,Lajoie, Barbora H.,Bouajila, Jalloul,Deharo, Eric,Sauvain, Michel,Tahar, Rachida,Basco, Leonardo,Pantaleo, Antonella,Turini, Francesco,Arese, Paolo,Valentin, Alexis,Thompson, Eloise,Vivas, Livia,Petit, Serge,Nallet, Jean-Pierre
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scheme or table
p. 699 - 714
(2010/07/09)
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- Solvent-free Sonogashira coupling reaction via high speed ball milling
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Herein, we report on the solvent-free Sonogashira reaction utilizing high speed ball milling. Sonogashira coupling of a variety of para substituted aryl halides were performed with trimethylsilylacetylene or phenylacetylene. We observed that iodo and bromo substituted aromatics successfully undergo Sonogashira coupling. However, chloro and fluoro substituted aryl compounds were unreactive. Conducting the coupling reaction in the absence of copper iodide led to low yields. Alternately, if the reaction is conducted with a copper ball in a copper vial in lieu of copper iodide, the coupling product is observed in high yields. This demonstrates the first report on the use of the vial and ball material as a catalyst in a ball milled chemical reaction. The Royal Society of Chemistry 2009.
- Fulmer, Dennis A.,Shearouse, William C.,Medonza, Shareika T.,MacK, James
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experimental part
p. 1821 - 1825
(2011/02/24)
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- MCM-41-supported bidentate phosphine palladium(0) complex as an efficient catalyst for the heterogeneous Stille reaction
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A Stille coupling reaction of organostannanes with organic halides has been developed in the presence of a catalytic amount of MCM-41-supported bidentate phosphine palladium(0) complex (0.5 mol %) in DMF/H2O (9:1) under air atmosphere in high yields. This polymeric palladium catalyst exhibits higher activity than Pd(PPh3)4 and can be reused at least 10 times without any decrease in activity.
- Zhao, Hong,Wang, Yue,Sha, Junchao,Sheng, Shouri,Cai, Mingzhong
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p. 7517 - 7523
(2008/12/20)
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- MCM-41-supported bidentate phosphine palladium(0) complex: a highly active and recyclable catalyst for the Sonogashira reaction of aryl iodides
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The first MCM-41-supported bidentate phosphine palladium(0) complex has been prepared. This complex is a highly efficient catalyst for Sonogashira reaction and can be reused at least 10 times without any decrease in activity.
- Cai, Mingzhong,Sha, Junchao,Xu, Qiuhua
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p. 4642 - 4647
(2007/10/03)
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- A novel and efficient synthesis of terminal arylacetylenes via Sonogashira coupling reactions catalysed by MCM-41-supported bidentate phosphine palladium(0) complex
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A variety of terminal arylacetylenes have been conveniently synthesised in good to high yields via Sonogashira coupling of aryl iodides with (trimethylsilyl)acetylene catalysed by a MCM-41-supported bidentate phosphine palladium(0) complex, followed by desilylation. The polymeric palladium catalyst can be reused many times without any decrease in activity.
- Wang, Yue,Huang, Bin,Sheng, Shouri,Cai, Mingzhong
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p. 728 - 732
(2008/09/20)
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- Enantioselective rhodium-catalyzed [2+2+2] cycloaddition of alkenyl isocyanates and terminal alkynes: Application to the total synthesis of (+)-lasubine II
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The use of TADDOL-based phosphoramidite ligands on rhodium allows for the incorporation of terminal alkynes in the [2+2+2] cycloaddition with alkenyl isocyanates. Terminal aliphatic alkynes provide bicyclic lactams, while the use of aryl alkynes provides complementary access to vinylogous amides. Product selectivity seems to be governed by a combination of electronics and sterics, with smaller and/or more electron-deficient substituents favoring lactam formation. The use of homologous alkenyl isocyanates leads to an expedient asymmetric total synthesis of the alkaloid lasubine II. Copyright
- Yu, Robert T.,Rovis, Tomislav
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p. 12370 - 12371
(2007/10/03)
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- Direct coupling reactions of alkynylsilanes catalyzed by palladium(II) chloride and a di(2-pyridyl)methylamine-derived palladium(II) chloride complex in water and in NMP
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Symmetrical internal alkynes can be prepared either by diarylation of mono- and bis(trimethylsilyl)acetylene (TMSA and BTMSA) catalyzed by ligand-less palladium(II) chloride or by a di(2-pyridyl) methylamine-derived palladium(II) chloride complex 1 (typic
- Gil-Molto, Juan,Najera, Carmen
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p. 1874 - 1882
(2007/10/03)
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- Rhodium-catalyzed regio- and enantioselective intermolecular [4+2] carbocyclization of 4-alkynals with N,N-dialkyl acrylamides
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(Chemical Equation Presented) Selective rings: A cationic Rh I-(R,R)-walphos complex catalyzes a highly regio-and enantioselective intermolecular [4+2] carbocyclization of 4-alkynals with N,N-dialkyl acrylamides to afford enantioenriched cyclohexanones (see scheme; cod = cycloocta-1,5-diene). This new route is attractive in view of the one-step access to 4-alkynals from commercially available reagents.
- Tanaka, Ken,Hagiwara, Yuji,Noguchi, Keiichi
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p. 7260 - 7263
(2007/10/03)
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- Homogeneous catalysts supported on soluble polymers: Biphasic Sonogashira coupling of aryl halides and acetylenes using MeOPEG-bound phosphine - Palladium catalysts for efficient catalyst recycling
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The Sonogashira coupling of various aryl bromides and iodides with different acetylenes was studied under biphasic conditions with soluble, polymer-modified catalysts to allow the efficient recycling of the homogeneous catalyst. For this purpose, several
- Koellhofer, Axel,Plenio, Herbert
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p. 1416 - 1425
(2007/10/03)
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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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- C(sp2)-C(sp) and C(sp)-C(sp) Coupling Reactions Catalyzed by Oxime-Derived Palladacycles
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Oxime-derived chloro-bridged palladacycle 8a, derived from 4,4′-dichlorobenzophenone, is an efficient pre-catalyst for the copper- and amine-free Sonogashira coupling between terminal acetylenes and aryl iodides and aryl and vinyl bromides achieving turnover numbers (TON) of up to 72000. Catalyst 8a has also been shown as a effective promoter for the sila-Sonogashira coupling between 1-(trimethylsilyl)alkynes and aryl iodides and bromides in the presence of CuI or Bu4NBr as co-catalysts. This complex also catalyzes efficiently the homocoupling reaction (Glaser-type coupling) between 1-alkynes in NMP at room temperature with TONs of up to 1000. All the reactions can be performed under air and employing reagent-grade chemicals under very low loading conditions, which demonstrates the versatility and high activity of oxime-derived palladacycles.
- Alonso, Diego A.,Na?jera, Carmen,Pacheco, Ma. Carmen
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p. 1146 - 1158
(2007/10/03)
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- Asymmetric synthesis of 1-aryl-1,2-ethanediols from arylacetylenes by palladium-catalyzed asymmetric hydrosilylation as a key step
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Double hydrosilylation of arylacetylenes with trichlorosilane catalyzed first by platinum and second by a chiral monophosphine-palladium complex generated the corresponding 1,2-bis(silyl)-1-arylethanes, the oxidation of which with hydrogen peroxide gave 1-aryl-1,2-diols of high enantiomeric purity (94-98% ee) in high yields. Copyright
- Shimada, Toyoshi,Mukaide, Kotaro,Shinohara, Akihiro,Han, Jin Wook,Hayashi, Tamio
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p. 1584 - 1585
(2007/10/03)
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- Palladium-catalyzed cross-alkynylation of aryl bromides by sodium tetraalkynylaluminates
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Sodium tetraalkynylaluminates (1-4), prepared from NaAlH4 and terminal alkynes, cross-couple with aryl bromides in the presence of Pd(0) and Pd(II) catalysts. The reactions take place in boiling THF or DME. The process is applicable to both hom
- Gelman, Dmitri,Tsvelikhovsky, Dmitry,Molander, Gary A.,Blum, Jochanan
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p. 6287 - 6290
(2007/10/03)
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- Alkyne oxidations by cis-dioxoruthenium(VI) complexes. A formal [3 + 2] cycloaddition reaction of alkynes with cis-[(Cn*)(CF3CO2)Ru(VI)O2]ClO4 (Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane)
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cis-Dioxoruthenium(VI) complexes, [Cn*(CF3CO2)Ru(VI)O2]ClO4 (1) (Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane) and cis-[(Tet-Me6)Ru(VI)O2](ClO4)2 (2) (Tet-Me6 = N,N,N',N'-tetramethyl-3,6-dimethyl-3,6-diazaoctane-1,8-diamine), oxidize disubstituted alkynes to 1,2-diketones selectively in good to excellent yields under ambient conditions. The reactions proceed via the formation of dark blue [(Cn*)(CF3CO2)Ru(IV)OC2R1R2O]+ intermediates, which display a characteristic UV-visible absorption band at 550-680 nm. With bis(trimethylsilyl)acetylene as substrate and 1 as the oxidant, the intermediate was isolated and structurally characterized by X-ray crystallography as a [3 + 2] cycloadduct. The kinetics of the cycloaddition of 1 with various substituted trimethylsilylacetylenes has been studied by stopped-flow spectrophotometry. With the exception of bis(trimethylsilyl)acetylene, the second-order rate constants were found to vary over a range of less than an order of magnitude irrespective of a 2.3 eV change of the calculated I(p) of the alkynes; therefore, a rate-limiting single electron-transfer mechanism is unlikely. The participation of oxirene (oxene insertion) and metallaoxetene ([2 + 2] cycloaddition) intermediates appears to be implausible based on product analysis. A linear Hammett correlation was established using σ+ and σ(jj)(G) parameters for the cycloaddition of 1 with para-substituted aryl trimethylsilylacetylenes, and the rate-limiting vinyl radical intermediate formation is proposed.
- Che,Yu,Chan,Cheng,Peng,Lau,Li
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p. 11380 - 11392
(2007/10/03)
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- Synthesis of 2-amino-6-phenyl-4H-pyran-4-ones
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The treatment of a series of phenylacetylenic β-keto amides with methanesulfonic acid produces a high yielding intramolecular cyclization to the corresponding 2-amino-6-phenyl-4H-pyran-4-ones.
- Morris,Wishka
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- Fungicidal pyridinylpyrimidine compounds
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Fungicidal compounds having the formula (I): STR1 wherein R1 is an optionally substituted phenyl group, C3-6 cycloalkyl optionally substituted by alkyl or alkyl; R2, R3, R4, R5, R6/su
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- Pyrimidine derivatives
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Pyrimidine derivatives useful as plant growth regulators and fungicides having the general formula (I): STR1 wherein Y is optionally substituted cyclopropyl or 1-methyl-cyclopropyl or is optionally halo-substituted isopropyl or t-butyl; R2 is a
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