- Method for promoting acylation of amine or alcohol by carbon dioxide
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The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
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Paragraph 0034-0035
(2021/05/29)
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- Steric effect of NHC ligands in Pd(II)–NHC-catalyzed non-directed C–H acetoxylation of simple arenes
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Although there has been a lot of progress in oxidative arene C–H functionalization reactions catalyzed by Pd(II/IV) system, the non-directed, site-selective functionalization of arene molecules is still challenging. It has been established that ligands play a pivotal role in controlling rate- as well as selectivity-determining step in a catalytic cycle involving well-defined metal-ligand bonding. N-heterocyclic carbene (NHC) ligands have had a tremendous contribution in the recent extraordinary success of achieving high reactivity and excellent selectivity in many catalytic processes including cross-coupling and olefin-metathesis reactions. However, the immense potential of these NHC ligands in improving site-selectivity of non-directed catalytic C–H functionalization reactions of simple arenes is yet to be realized, where overriding the electronic bias on deciding selectivity is a burdensome task. The presented work demonstrated an initiative step in this regard. Herein, a series of well-defined discrete [Pd(NHCR′R)(py)I2] complexes with systematically varied degree of spatial congestion at the Pd centre, exerted through the R and R’ substituents on the NHC ligand, were explored in controlling the activity as well as the site-selectivity of non-directed acetoxylation of representative monosubstituted and disubstituted simple arenes (such as toluene, iodobenzene and bromobenzene, naphthalene and 1,2-dichlorobenzene). The resulting best yields were found to be 75% for toluene and 65% for bromobenzene with [Pd(NHCMePh)(py)I2], 75% for iodobenzene and 79% for naphthalene with [Pd(NHCMeMe)(py)I2], and 41% for 1,2-dichlorobenzene with [Pd(NHCCyCy)(py)I2]. Most importantly, with increasing the bulkiness of the NHC ligand in the complexes, the selectivity of the distal C-acetoxylated products in comparison to the proximal ones, was enhanced to a great extent in all cases. Considering the vast library of NHC ligands, this study underscores the future opportunity to develop more strategies to improve the activity and the crucial site-selectivity of C–H functionalization reactions in simple as well as complex organic molecules.
- Mandal, Tanmoy,Yadav, Sudha,Choudhury, Joyanta
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- Acyl-based donor molecules
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Problem: To provide acyl-based donor molecules that enable acylization of the target molecule at high efficiency and acylizing agents using the molecule as an active ingredient.Solution: Compounds having the following structure and acylated agents using the compound as an active ingredient.【Chemical 1】(R indicates acyl group, X indicates hydrophilic group)【Selection diagram】 None
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Paragraph 0077
(2021/12/07)
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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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- Development of an Enzyme-Inhibitor Reaction Using Cellular Retinoic Acid Binding Protein II for One-Pot Megamolecule Assembly
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This paper presents an enzyme building block for the assembly of megamolecules. The system is based on the inhibition of the human-derived cellular retinoic acid binding protein II (CRABP2) domain. We synthesized a synthetic retinoid bearing an arylfluoro
- Kimmel, Blaise R.,Mrksich, Milan
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supporting information
p. 17843 - 17848
(2021/11/22)
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- Permeant fluorescent probes visualize the activation of sarm1 and uncover an antineurodegenerative drug candidate
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SARM1 regulates axonal degeneration through its NAD-metabolizing activity and is a drug target for neurodegenerative disorders. We designed and synthesized fluorescent conjugates of styryl derivative with pyridine to serve as substrates of SARM1, which exhibited large red shifts after conversion. With the conjugates, SARM1 activation was visualized in live cells following elevation of endogenous NMN or treatment with a cell-permeant NMN-analog. In neurons, imaging documented mouse SARM1 activation preceded vincristine-induced axonal degeneration by hours. Library screening identified a derivative of nisoldipine (NSDP) as a covalent inhibitor of SARM1 that reacted with the cysteines, especially Cys311 in its ARM domain and blocked its NMN-activation, protecting axons from degeneration. The Cryo-EM structure showed that SARM1 was locked into an inactive conformation by the inhibitor, uncovering a potential neuroprotective mechanism of dihydropyridines.
- Cai, Yang,Cao, Sheng,Du, Yang,Hou, Yun Nan,Huang, Ke,Lee, Chi-Sing,Lee, Hon Cheung,Li, Wan Hua,Wang, Qian Wen,Wang, Sujing,Xie, Xu Jie,Zhang, Hongmin,Zhao, Yong Juan,Zhao, Zhi Ying,Zhu, Wen Jie
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- 7-Siloxy-Substituted Hexahydronaphthalene Derivatives: Samarium Diiodide Promoted Synthesis and Typical Reactions
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The samarium diiodide promoted reductive cyclization of a series of γ-aryl ketones with acetoxy, alkoxy, and siloxy groups in ortho -, meta -, and para -positions was investigated. Only precursors with p -acetoxy, p - tert -butoxy, or p -siloxy substituen
- Niermann, André,Reissig, Hans-Ulrich
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supporting information
p. 2721 - 2730
(2020/09/15)
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- Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
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The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
- Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
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supporting information
p. 3866 - 3870
(2019/05/24)
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- Regioselectivity Influences in Platinum-Catalyzed Intramolecular Alkyne O-H and N-H Additions
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The steric and electronic drivers of regioselectivity in platinum-catalyzed intramolecular hydroalkoxylation are elucidated. A branch point is found that divides the process between 5-exo and 6-endo selective processes, and enol ethers can be accessed in good yields for both oxygen heterocycles. The main influence arises from an electronic effect, where the alkyne substituent induces a polarization of the alkyne that leads to preferential heteroatom attack at the more electron-deficient carbon. The electronic effects are studied in other contexts, including hydroacyloxylation and hydroamination, and similar trends in directionality are predominant although not uniformly observed.
- Costello, Jeff P.,Ferreira, Eric M.
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supporting information
p. 9934 - 9939
(2019/12/24)
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- Galloyl esters of trans-stilbenes are inhibitors of FASN with anticancer activity on non-small cell lung cancer cells
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Fatty acid synthase (FASN) is a lipogenic enzyme that is selectively upregulated in malignant cells. There is growing consensus on the oncogenicity of FASN-driven lipogenesis and the potential of FASN as a druggable target in cancer. Here, we report the synthesis and FASN inhibitory activities of two novel galloyl esters of trans-stilbene EC1 and EC5. Inhibition of FASN was accompanied by a loss in AKT activation and profound apoptosis in several non-small cell lung cancer (NSCLC) cells at the growth inhibitory concentrations of EC1 and EC5. Both FASN and phospho-AKT levels were concurrently downregulated. However, addition of a lipid concentrate to the treated cells reinstated cell viability and reversed the loss of FASN and AKT protein levels, thus recapitulating the causal relationship between FASN inhibition and the loss in cell viability.
- Tan, Yu-Jia,Ali,Tee, Sheng-Yang,Teo, Jun-Ting,Xi, Yu,Go, Mei-Lin,Lam
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- Efficient Syntheses of Diverse, Medicinally Relevant Targets Planned by Computer and Executed in the Laboratory
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The Chematica program was used to autonomously design synthetic pathways to eight structurally diverse targets, including seven commercially valuable bioactive substances and one natural product. All of these computer-planned routes were successfully executed in the laboratory and offer significant yield improvements and cost savings over previous approaches, provide alternatives to patented routes, or produce targets that were not synthesized previously. Although computers have demonstrated the ability to challenge humans in various games of strategy, their use in the automated planning of organic syntheses remains unprecedented. As a result of the impact that such a tool could have on the synthetic community, the past half century has seen numerous attempts to create in silico chemical intelligence. However, there has not been a successful demonstration of a synthetic route designed by machine and then executed in the laboratory. Here, we describe an experiment where the software program Chematica designed syntheses leading to eight commercially valuable and/or medicinally relevant targets; in each case tested, Chematica significantly improved on previous approaches or identified efficient routes to targets for which previous synthetic attempts had failed. These results indicate that now and in the future, chemists can finally benefit from having an “in silico colleague” that constantly learns, never forgets, and will never retire. Multistep synthetic routes to eight structurally diverse and medicinally relevant targets were planned autonomously by the Chematica computer program, which combines expert chemical knowledge with network-search and artificial-intelligence algorithms. All of the proposed syntheses were successfully executed in the laboratory and offer substantial yield improvements and cost savings over previous approaches or provide the first documented route to a given target. These results provide the long-awaited validation of a computer program in practically relevant synthetic design.
- Klucznik, Tomasz,Mikulak-Klucznik, Barbara,McCormack, Michael P.,Lima, Heather,Szymku?, Sara,Bhowmick, Manishabrata,Molga, Karol,Zhou, Yubai,Rickershauser, Lindsey,Gajewska, Ewa P.,Toutchkine, Alexei,Dittwald, Piotr,Startek, Micha? P.,Kirkovits, Gregory J.,Roszak, Rafa?,Adamski, Ariel,Sieredzińska, Bianka,Mrksich, Milan,Trice, Sarah L.J.,Grzybowski, Bartosz A.
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supporting information
p. 522 - 532
(2018/03/21)
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- Direct Pd(II)-Catalyzed Site-Selective C5-Arylation of 2-Pyridone Using Aryl Iodides
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A straightforward Pd(II)-catalyzed general strategy was developed for the C5-selective arylation of the 2-pyridone core with easily available aryl iodides. The transformation was highly regioselective and accomplished with a wide scope and functional group tolerance. Silver nitrate played a crucial role in this direct site-selective arylation. The method was extended to synthesize biologically active molecules.
- Maity, Saurabh,Das, Debapratim,Sarkar, Souradip,Samanta, Rajarshi
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supporting information
p. 5167 - 5171
(2018/09/13)
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- NOVEL AROMATIC COMPOUND AND USE THEREOF
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Provided is a compound showing a bone formation promoting action (and/or bone resorption suppressive action). A compound of the formula (I) or a pharmacologically acceptable salt: [wherein each substituent is as defined in the DESCRIPTION], has low toxicity, shows good pharmacokinetics, has an action to promote bone formation, and is useful for the prophylaxis or To treatment of metabolic bone diseases (osteoporosis, fibrous osteitis (hyperparathyroidism), osteomalacia, Paget's disease that influences the systemic bone metabolism parameter etc.) associated with a decrease in the bone formation ability as compared to the bone resorption capacity.
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-
Paragraph 0829-0831
(2016/08/17)
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- Synthesis, structure and multifunctional catalytic properties of a Cu(i)-coordination polymer with outer-hanging CuBr2
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A 1D Cu(i)-coordination polymer [(CuL1)(CuBr2), 1] carrying external copper bromide moieties was synthesized. The outer-hanging [CuBr2]- moiety is attached to the 1D Cu(i)-CP backbone via a Cu?Cu bonding interaction, which makes it look like a coordination polymer supported CuBr2 species. 1 exhibits excellent multifunctional catalytic activity for phenol acetylation, A3-coupling (aldehyde-alkyne-amine) and styrene oxide methanolysis reactions. Its heterogeneous catalytic nature was confirmed by solution leaching experiment and it can be reused without significant loss of its catalytic activity and selectivity for the above reactions.
- Zhu, Neng-Xiu,Zhao, Chao-Wei,Yang, Jing,Wang, Xue-Ru,Ma, Jian-Ping,Dong, Yu-Bin
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p. 108645 - 108653
(2016/11/30)
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- Total synthesis of the resveratrol oligomers (±)-Ampelopsin B and (±)-σ-Viniferin
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The total synthesis of the resveratrol dimers (±)-ampelopsin B and (±)-σ-viniferin is reported. Highlights of the approach include the use of cyclopropylmethyl groups to protect aromatic alcohols. This group allows an acid promoted three-step, one-pot dep
- Lindgren, Anders E. G.,?berg, Christopher T.,Hillgren, J. Mikael,Elofsson, Mikael
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supporting information
p. 426 - 429
(2016/02/18)
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- Extended Naphthalene Diimides with Donor/Acceptor Hydrogen-Bonding Properties Targeting G-Quadruplex Nucleic Acids
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Naphthalene diimides with one or two centrosymmetric arylethynyl moieties capable of synergic donor and acceptor hydrogen bonding exhibit promising binding properties and selectivity towards parallel G-quadruplex (G4) nucleic acids (c-myc, bcl-2 and parallel hTel22). The hydrogen-bonding network involving the phosphate backbone and outside rim of the G-quartet represents an opportunity to exploit G4 selectivity for extended aromatics.
- Doria, Filippo,Nadai, Matteo,Costa, Giosuè,Sattin, Giovanna,Gallati, Caroline,Bergamaschi, Greta,Moraca, Federica,Alcaro, Stefano,Freccero, Mauro,Richter, Sara N.
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p. 4824 - 4833
(2016/10/13)
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- Palladium-Catalyzed Desilylative Acyloxylation of Silicon-Carbon Bonds on (Trimethylsilyl)arenes: Synthesis of Phenol Derivatives from Trimethylsilylarenes
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A strategy for desilylative acetoxylation of (trimethylsilyl)arenes has been developed in which (trimethylsilyl)arenes are converted into acetoxyarenes. The direct acetoxylation is performed in the presence of 5 mol % of Pd(OAc)2 and PhI(OCOCF3)2 (1.5 equiv) in AcOH at 80°C for 17 h. The acetoxyarenes are obtained in good to high yields (67-98%). The synthetic utility is demonstrated with a one-pot transformation of (trimethylsilyl)arenes to phenols by successive acetoxylation and hydrolysis. Furthermore, desilylative acyloxylation of 2-(trimethylsilyl)naphthalene using several carboxylic acids has been conducted.
- Gondo, Keisuke,Oyamada, Juzo,Kitamura, Tsugio
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supporting information
p. 4778 - 4781
(2015/10/12)
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- Hypervalent Activation as a Key Step for Dehydrogenative ortho C-C Coupling of Iodoarenes
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Building on earlier results, a direct metal-free α- arylation of substituted cyclic 1,3-diones using ArI(O2CCF3)2 reagents has been developed; unlike other arylative approaches, the arylated products retain the iodine substituent ortho to the newly formed C-C bond. The mechanism is explored by using DFT calculations, which show a vanishingly small activation barrier for the C-C bond-forming step. In fact, taking advantage of an efficient in situ hypervalent activation, the iodoarenes are shown to undergo a cross- dehydrogenative C-C coupling at the C-H ortho to the iodine. When Oxone is used as terminal oxidant, the process is found to benefit from a rapid initial formation of the hypervalent ArI(OR)2 species and the sulfate-accelerated final coupling with a ketone. This method complements the ipso selectivity obtained in the metal-catalyzed α-arylation of carbonyl compounds.
- Wu, Yichen,Arenas, Ismael,Broomfield, Lewis Marc,Martin, Eddy,Shafir, Alexandr
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p. 18779 - 18784
(2016/01/25)
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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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- Aryl ethynyl anthraquinones: A useful platform for targeting telomeric G-quadruplex structures
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Aryl ethynyl anthraquinones have been synthesized by Sonogashira cross-coupling and evaluated as telomeric G-quadruplex ligands, by the FRET melting assay, circular dichroism, the DNA synthesis arrest assay and molecular docking. Both the binding properti
- Percivalle, Claudia,Sissi, Claudia,Greco, Maria Laura,Musetti, Caterina,Mariani, Angelica,Artese, Anna,Costa, Giosuè,Perrore, Maria Lucia,Alcaro, Stefano,Freccero, Mauro
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supporting information
p. 3744 - 3754
(2014/06/09)
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- Ti/Ni-mediated inter- and intramolecular conjugate addition of aryl and alkenyl halides and triflates
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In this work, we show that the unique combination of a nickel catalyst and Cp2TiCl allows the direct conjugate addition of aryl and alkenyl iodides, bromides, and to a lesser extent, chlorides and triflates to α,β-unsaturated carbonyls at room temperature, without requiring the previous formation of an organometallic nucleophile. The reaction proceeds inter- and intramolecularly with good functional group compatibility, which is key for the development of free protecting group methodologies. Carbo- and heterocycles of five- and six-membered rings are obtained in good yields. Moreover, some insights about the mechanism involved have been obtained from cyclic voltammetry, UV-vis, and HRTEM measurements.
- Marquez, Irene R.,Miguel, Delia,Millan, Alba,Marcos, M. Luisa,De Cienfuegos, Luis Alvarez,Campana, Araceli G.,Cuerva, Juan M.
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p. 1529 - 1541
(2014/03/21)
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- A universal procedure for the [18F]trifluoromethylation of aryl iodides and aryl boronic acids with highly improved specific activity
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Herein we describe a valuable method for the introduction of the [18F]CF3 group into arenes with highly improved specific activity by the reaction of [18F]trifluoromethane with aryl iodides or aryl boronic acids. This [su
- Vanderborn, Dion,Sewing, Claudia,Herscheid,Windhorst, Albert D.,Orru, Romano V. A.,Vugts, Danielle J.
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supporting information
p. 11046 - 11050
(2015/03/30)
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- Hydrosoluble and solvatochromic naphthalene diimides with NIR absorption
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Mimicking biochromophore anions containing phenolate moieties, eight conjugated naphthalene diimides (NDIs) have been synthesized in order to develop probes, displaying charge-transfer transitions affected by the nearby environment. NIR absorption of the resulting phenolates and their solvatochromic properties in both organic solvents and water are described.
- Doria, Filippo,Gallati, Caroline Marie,Freccero, Mauro
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p. 7838 - 7842
(2013/11/19)
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- The role of cyclobutenes in gold(I)-catalysed skeletal rearrangement of 1,6-enynes
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1,6-Enynes with electron-donating substituents at the alkyne undergo gold(i)-catalysed single cleavage skeletal rearrangement, whereas substrates with electron-withdrawing substituents evolve selectively to double cleavage rearrangement. Theoretical calcu
- Escribano-Cuesta, Ana,Perez-Galan, Patricia,Herrero-Gomez, Elena,Sekine, Masaki,Braga, Ataualpa A. C.,Maseras, Feliu,Echavarren, Antonio M.
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supporting information; experimental part
p. 6105 - 6111
(2012/09/05)
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- Silver triflate catalyzed acetylation of alcohols, thiols, phenols, and amines
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A variety of alcohols, thiols, phenols, and amines were subjected to acetylation reaction using acetic anhydride in the presence of catalytic quantity of silver triflate. The method described has a wide range of applications, proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time. Georg Thieme Verlag Stuttgart · New York.
- Das, Rima,Chakraborty, Debashis
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experimental part
p. 1621 - 1625
(2011/06/25)
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- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
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Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
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experimental part
p. 641 - 649
(2011/03/19)
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- Selective synthesis and biological evaluation of sulfate-conjugated resveratrol metabolites
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Five resveratrol sulfate metabolites were synthesized and assessed for activities known to be mediated by resveratrol: inhibition of tumor necrosis factor (TNF) α induced NFkB activity, cylcooxygenases (COX-1 and COX-2), aromatase, nitric oxide
- Hoshino, Juma,Park, Eun-Jung,Kondratyuk, Tamara P.,Marler, Laura,Pezzuto, John M.,Van Breemen, Richard B.,Mo, Shunyan,Li, Yongchao,Cushman, Mark
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experimental part
p. 5033 - 5043
(2010/09/16)
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- Phenolic bis-styrylbenzenes as β-amyloid binding ligands and free radical scavengers
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Starting from bisphenolic bis-styrylbenzene DF-9 (4), β-amyloid (Aβ) binding affinity and specificity for phenolic bis-styrylbenzenes, monostyrylbenzenes, and alkyne controls were determined by fluorescence titration with β-amyloid peptide Aβ1-40 and a fluorescence assay using APP/PS1 transgenic mouse brain sections. Bis-styrylbenzene SAR is derived largely from work on symmetrical compounds. This study is the first to describe Aβ binding data for bis-styrylbenzenes unsymmetrical in the outer rings. With one exception, binding affinity and specificity were decreased by adding and/or changing the substitution pattern of phenol functional groups, changing the orientation about the central phenyl ring, replacing the alkene with alkyne bonds, or eliminating the central phenyl ring. The only compound with an Aβ binding affinity and specificity comparable to 4 was its 3-hydroxy regioisomer 8. Like 4, 8 crossed the blood-brain barrier and bound to Aβ plaques in vivo. By use of a DPPH assay, phenol functional groups with para orientations seem to be a necessary, but insufficient, criterion for good free radical scavenging properties in these compounds.
- Flaherty, Daniel P.,Kiyota, Tomomi,Dong, Yuxiang,Ikezu, Tsuneya,Vennerstrom, Jonathan L.
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supporting information; experimental part
p. 7992 - 7999
(2011/03/19)
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- Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, and thiols in room temperature Ionic liquids
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Ruthenium(III) chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature) in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]). The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.
- Xi, Zhiwen,Hao, Wenyan,Wang, Pingping,Cai, Mingzhong
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experimental part
p. 3528 - 3537
(2009/12/24)
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- A templating approach for monodisperse self-assembled organic nanostructures
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The precise structural control is known for self-assembly into closed spherical structures (e.g., micelles), but similar control of open structures is much more challenging. Inspired by natural tobacco mosaic virus, we present the use of a rigid-rod template to control the size of a one-dimensional self-assembly. We believe that this strategy is novel for organic self-assembly and should provide a general approach to controlling size and dimension. Copyright
- Bull, Steve R.,Palmer, Liam C.,Fry, Nathaniel J.,Greenfield, Megan A.,Messmore, Benjamin W.,Meade, Thomas J.,Stupp, Samuel I.
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p. 2742 - 2743
(2008/09/20)
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- Beyond Aresta's complex: Ni- and Pd-catalyzed organozinc coupling with CO2
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Organozinc reagents are widely used in organic synthesis due primarily to their high functional group compatibility. However, under mild conditions, these organometallic reagents do not react directly with CO2, the ideal C1 source for organic synthesis. Herein, we report that both Ni and Pd complexes can catalyze the addition of organozinc reagents to CO2 under mild conditions (1 atm CO2, 0 °C). This transformation represents an important extension of the Negishi cross-coupling and is believed to occur via a novel mechanism involving Aresta-s complex and/or its corresponding Pd analogue. Copyright
- Yeung, Charles S.,Dong, Vy M.
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supporting information; experimental part
p. 7826 - 7827
(2009/02/02)
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- Polymer-supported gadolinium triflate as a convenient and efficient Lewis acid catalyst for acetylation of alcohols and phenols
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A polymer-supported gadolinium triflate (CMPS-IM-Gd) catalyst was prepared from chloromethyl polystyrene (CMPS) resin using a simple and convenient procedure. This polymeric catalyst was used as an efficient Lewis acid catalyst for the acetylation of various alcohols and phenols with acetic anhydride, affording high yields under mild conditions. The reaction was completed in a short period of time with small amounts of the catalyst. The catalyst was reused over 10 times without any significant loss of its catalytic activity.
- Yoon, Hyo-Jin,Lee, Sang-Myung,Kim, Jong-Ho,Cho, Hong-Jun,Choi, Jung-Woo,Lee, Sang-Hyeup,Lee, Yoon-Sik
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p. 3165 - 3171
(2008/09/20)
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- Efficient Baeyer-Villiger oxidation of ketones using molecular iodine/H2O2 as heterogeneous catalytic system
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The use of molecular iodine as a catalyst for the oxidation of ketones using hydrogen peroxide in the presence of acetic acid at room temperature is reported. Copyright Taylor & Francis Group, LLC.
- Gaikwad, Digambar D.,Dake, Satish A.,Kulkarni, Ravibhushan S.,Jadhav, Wamanrao N.,Kakde, Shankar B.,Pawar, Rajendra P.
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p. 4093 - 4097
(2008/03/12)
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- Palladium-catalyzed alkylation-hydride reduction sequence: Synthesis of meta-substituted arenes
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(Chemical Equation Presented) A new three-component, palladium-catalyzed domino reaction which gives access to meta-substituted arenes using aryl iodides and primary alkyl halides is reported. Various functional groups are tolerated on both the aryl iodide and alkyl halide. In addition, isotopic labeling studies provide insight into the mechanism of this Catellani-type reaction.
- Wilhelm, Thorsten,Lautens, Mark
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p. 4053 - 4056
(2007/10/03)
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- Diflunisal Analogues Stabilize the Native State of Transthyretin. Potent Inhibition of Amyloidogenesis
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Analogues of diflunisal, an FDA-approved nonsteroidal antiinflammatory drug (NSAID), were synthesized and evaluated as inhibitors of transthyretin (TTR) aggregation, including amyloid fibril formation. High inhibitory activity was observed for 26 of the compounds. Of those, eight exhibited excellent binding selectivity for TTR in human plasma (binding stoichiometry > 0.50, with a theoretical maximum of 2.0 inhibitors bound per TTR tetramer). Biophysical studies reveal that these eight inhibitors dramatically slow tetramer dissociation (the rate-determining step of amyloidogenesis) over a duration of 168 h. This appears to be achieved through ground-state stabilization, which raises the kinetic barrier for tetramer dissociation. Kinetic stabilization of WT TTR by these eight inhibitors is further substantiated by the decreasing rate of amyloid fibril formation as a function of increasing inhibitor concentration (pH 4.4). X-ray cocrystal structures of the TTR·182 and TTR·202 complexes reveal that 18 and 20 bind in opposite orientations in the TTR binding site. Moving the fluorines from the meta positions in 18 to the ortho positions in 20 reverses the binding orientation, allowing the hydrophilic aromatic ring of 20 to orient in the outer binding pocket where the carboxylate engages in favorable electrostatic interactions with the ε-ammonium groups of Lys 15 and 15′. The hydrophilic aryl ring of 18 occupies the inner binding pocket, with the carboxylate positioned to hydrogen bond to the serine 117 and 117′ residues. Diflunisal itself appears to occupy both orientations based on the electron density in the TTR·12 structure. Structure-activity relationships reveal that para-carboxylate substitution on the hydrophilic ring and dihalogen substitution on the hydrophobic ring afford the most active TTR amyloid inhibitors.
- Adamski-Werner, Sara L.,Palaninathan, Satheesh K.,Sacchettini, James C.,Kelly, Jeffery W.
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p. 355 - 374
(2007/10/03)
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- Solid-phase synthesis of lamellarins Q and O
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An efficient solid phase synthesis of the pyrrole-based alkaloids lamellarins Q and O using Merrifield resin and N-protected methyl 3,4-dibromopyrrole-2-carboxylate as a scaffold is described.
- Marfil, Marta,Albericio, Fernando,álvarez, Mercedes
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p. 8659 - 8668
(2007/10/03)
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- Polymerizable mesogenic tolanes
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Polymerizable tolanes of formula I wherein P, Sp, X, n, A1, A2, Z1, Z2, m1, m2, L1, L2, r and R have the meanings defined herein, polymerizable liquid crystal compositions comprising at lea
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- Reactivity and synthetic utility of 1-(arenesulfonyloxy) benziodoxolones
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The reactivity and synthetic use of 1-(arenesulfonyloxy)benziodoxolones were studied. In the presence of iodine, 1-(arenesulfonyloxy)benziodoxolones iodinated various aromatics to give iodoarenes in moderate to good yields. In particular, 1-(p-chlorobenzenesulfonyloxy)benziodoxolone showed the best reactivity. Using a halide salt such as lithium bromide or lithium chloride instead of iodine, the corresponding aryl bromides and chlorides were also obtained in good yields. In the absence of aromatics, 1- (arenesulfonyloxy)benziodoxolones gave rise to desulfonyloxyiodination reactions to give the corresponding aryl iodides via electrophilic ipso substitution on the aromatic rings. Furthermore, the l-(p- toluenesulfonyloxy)benziodoxolone/iodine system iodotosyloxylated alkynes in good yields. These reactions proceeded via the formation of arenesulfonyl hypoiodites.
- Muraki, Takahito,Togo, Hideo,Yokoyama, Masataka
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p. 2883 - 2889
(2007/10/03)
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- Synthetic use of 1-(p-toluenesulfonyloxy)-1,2-benziodoxol-3(1H)-one: Iodination of aromatic rings
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Treatment of various aromatic compounds with 1-(p-toluenesulfonyloxy)-1,2-benziodoxol-3(1H)-one 1A and iodine gave the corresponding iodinated compounds in good yields. Similarly, chlorination and bromination proceeded effectively. As compared with other trivalent iodine compounds, the iodinane 1A showed the best reactivity as a halogenation reagent.
- Muraki, Takahito,Togo, Hideo,Yokoyama, Masataka
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p. 286 - 288
(2007/10/03)
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- An efficient and regioselective direct aromatic iodination using iodine and nitrogen dioxide
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Direct iodination of a variety of aromatic compounds is achieved by using nitrogen dioxide as an oxidant in addition to iodine. The reaction affords aromatic monoidodides m high yields with high para-regioselectivity. 4,4'- Diiodo binuclear compounds are also obtained effectively by controlling the stoichiometry.
- Noda, Yumiki,Kashima, Mikito
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p. 6225 - 6228
(2007/10/03)
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- Highly efficient and selective procedures for the synthesis of γ-alkylidenebutenolides via palladium-catalyzed ene-yne coupling and palladium- or silver-catalyzed lactonization of (Z)-2-en-4-ynoic acids. Synthesis of rubrolides A, C, D, and E
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The diacetates of rubrolides A, C, D, and E (1 a-d) were prepared in modest yields by the Pd-catalyzed cross coupling-lactonization tandem reaction of 5a or 5b with 6a or 6b using Cl2Pd(PPh3)2 and CuI as catalysts. The feasibility of converting the diacetates into rubrolides was demonstrated by the synthesis of rubrolide C by treatment of 1b with methanolic K2CO3 in THF. A detailed investigation of various parameters and conditions has indicated that formation of the corresponding six-membered lactones 7 and/or the cross coupling-lactonization-Heck substitution products 11 can be serious side reactions under non-optimized conditions and that the use of Pd(PPh3)4 rather than phosphine-free complexes, e.g., CI2Pd(PhCN)2, or complexes of low phosphine content, e.g., Cl2Pd(PPh3)2, along with CuI and NEt3 in MeCN provides satisfactory conditions for the cross coupling-lactonization tandem reaction. Thus, the diacetate of rubrolide A (1a) was prepared in 70% isolated yield. The optimized conditions reported herein appear to be generally applicable to the stereoselective and regioselective synthesis of γ-alkylidenebutenolides in a highly efficient manner.
- Kotora, Matin,Negishi, Ei-Ichi
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p. 121 - 128
(2007/10/03)
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- Antimuscarinic 3-(2-Furanyl)quinuclidin-2-ene derivatives: Synthesis and structure-activity relationships
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A series of 25 derivatives of the muscarinic antagonist 3-(2- furanyl)quinuclidin-2-ene (4) was synthesized and evaluated for muscarinic and antimuscarinic properties. Substitution at all three positions of the furan ring has been investigated. The affini
- Johansson, Gary
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p. 3804 - 3819
(2007/10/03)
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- Highly Selective Cross-Coupling Reactions of Aryl(halo)silanes with Aryl Halides: A General and Practical Route to Functionalized Biaryls
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The palladium catalyzed cross-coupling reaction of aryl halides with aryl(halo)silanes (halogen=F, Cl) gives good yields of unsymmetrical biaryls and p-terphenyls.The reaction takes place smoothly in N,N-dimethylformamide in the presence of an appropriate palladium catalyst and potassium fluoride.Since this reaction is tolerant of a variety of reactive functional groups, highly functionalized 4,4'-, 3,4'-, 2,4'- and even sterically crowded 2,2'-disubstituted biaryls can be obtained in moderate to high yields.The synthetic utility of the method has been demonstrated by its application to a short synthesis of liquid crystals.Mechanistic aspects of transmetalation of an aryl(fluoro)silicate intermediate with a palladium complex are discussed on the basis of the substituent effects on the rate of the cross-coupling reactions.
- Hatanaka, Yasuo,Goda, Ken-ichi,Okahara, Yoshinori,Hiyama, Tamejiro
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p. 8301 - 8316
(2007/10/02)
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- A CONVENIENT MASKING GROUP FOR ARYL IODIDES
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1-Aryl-3,3-dialkyltriazenes give excellent yields of easily isolated aryl iodides upon treatment with methyl iodide.
- Moore, Jeffrey S.,Weinstein, Edward J.,Wu, Ziyan
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p. 2465 - 2466
(2007/10/02)
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- A Novel Aromatic Iodination Method Using F2
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A new method for direct aromatic iodination with IF, made in situ from the corresponding elements, is described.Depending on the reaction time and temperature, mono- or polyiodination can be achieved.Even deactivated aromatic rings can be directly iodinated without the presence of any Friedel-Crafts catalyst.Sensitive groups such as aromatic aldehydes are not affected by the reagent.
- Rozen, Shlomo,Zamir, Dov
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p. 3552 - 3555
(2007/10/02)
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