- Effects of surface monolayers on the electron-transfer kinetics and adsorption of methyl viologen and phenothiazine derivatives on glassy carbon electrodes
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Five organic redox systems were examined in aqueous electrolytes on polished and chemically modified glassy carbon (GC), to evaluate the effects of surface structure on the heterogeneous transfer rate constant, k°. Methyl viologen reduction to its cation radical exhibited a voltammetric peak potential difference which was insensitive to surface modification, with k°decreasing by only 50% when a chemisorbed monolayer was present. Methylene blue and three other phenothiazines adsorbed to polished GC, but the adsorption was suppressed by surface modification. For all four phenothiazines, chemisorbed or physisorbed monolayers of electroinactive species had minor effects on k°, with a compact nitrophenyl monolayer decreasing k°by 50%. This minor change in k°was accompanied by a major decrease in adsorption, apparently due to inhibition of dipole-dipole or π- π interactions between the phenothiazine and GC. Chlorpromazine oxidation to its cation radical was studied in more detail, under conditions where adsorption was suppressed. A plot of the natural log of the observed rate constant vs the monolayer thickness for a variety of chemisorbed monolayers was linear, with a slope of -0.22 A-1. The observations are consistent with a through-bond electron-tunneling mechanism for electron transfer to all five redox systems studied. The tunneling constant for CPZ of 0.22 A-1 is between that reported for electron tunneling through conjugated polyene spacers (0.14 A-1) and that reported for phenyl-methylene spacers (0.57 A-1), on the basis of long-range electron transfer in rigid molecules.
- Yang, Hseuh-Hui,McCreery
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Read Online
- 4-(4-methoxyphenylamino)-3-phenylazo-3-penten-2-one
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The title compound, C18H19N3O2, was obtained by an azocoupling reaction with enaminones and is composed of a planar azoenamine skeleton which forms a six-membered ring through a symmetrical intramolecular hydrogen bond. The compound was found to exist as an equilibrium mixture of major hydrazoimino and minor azoenamine tautomers. Quantification of the relative contribution of the tautomeric forms is obscured by the existence of the hydrogen bond. Comparison of the results with those obtained for a similar structure revealed a substantial effect on the tautomeric equilibria of the nature of the substituent bonded to the amine nitrogen.
- Kettmann,Lokaj,Simunek,Machacek
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Read Online
- Irreversible tautomerization as a powerful tool to access unprecedented functional porous organic polymers with a tris(β-keto-hydrazo)cyclohexane subunit (TKH-POPs)
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Porous organic polymers (POPs) have received much attention, due to their multiple potential applications and flexibility in chemical structure design. Creation of a novel chemical structure has been the central task in the research of POPs, which are usually constructed by direct coupling polymerizations. The fascinating rearrangement/tautomerization could lead to some novel structures, which are hard to access by conventional direct coupling polymerizations. Herein, the tautomerization from tris(β-hydroxyl-azo)benzene to the tris(β-keto-hydrozo)cyclohexane structure has been proved unambiguously based on an advanced 2D NMR technique such as 15N-1H-HSQC and 1H-1H-NOESY. The crucial tautomerization was used to synthesize TKH-POPs for the first time. The as-synthesized TKH-POP-1 was found to have an adsorption capacity as high as 66.3 mmol g-1 (at 273 K and P/P0 = 0.98) towards acetonitrile vapor, which was the highest among all the reported materials. The general and flexible strategy to make functional POPs with tunable pores such as ultramicropores, micropores and mesopores will help develop interesting functional POPs in the near future.
- Liu, Xiangxiang,Luo, Xian-Sheng,Fu, Hao-Xi,Fan, Wenhao,Chen, Shi-Lu,Huang, Mu-Hua
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Read Online
- Aqueous and Visible-Light-Promoted C-H (Hetero)arylation of Uracil Derivatives with Diazoniums
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Direct C5 (hetero)arylation of uracil and uridine substrates with (hetero)aryl diazonium salts under photoredox catalysis with blue light was reported. The coupling proceeds efficiently with diazonium salts and heterocycles in good functional group tolerance at room temperature in aqueous solution without transition-metal components. A plausible radical mechanism has been proposed.
- Liu, An-Di,Wang, Zhao-Li,Liu, Li,Cheng, Liang
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p. 16434 - 16447
(2021/11/16)
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- Azoacetylenes for the Synthesis of Arylazotriazole Photoswitches
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We report a modular approach toward novel arylazotriazole photoswitches and their photophysical characterization. Addition of lithiated TIPS-acetylene to aryldiazonium tetrafluoroborate salts gives a wide range of azoacetylenes, constituting an underexplored class of stable intermediates.In situdesilylation transiently leads to terminal arylazoacetylenes that undergo copper-catalyzed cycloadditions (CuAAC) with a diverse collection of organoazides. These include complex molecules derived from natural products or drugs, such as colchicine, taxol, tamiflu, and arachidonic acid. The arylazotriazoles display near-quantitative photoisomerization and long thermalZ-half-lives. Using the method, we introduce for the first time the design and synthesis of a diacetylene platform. It permits implementation of consecutive and diversity-oriented approaches linking two different conjugants to independently addressable acetylenes within a common photoswitchable azotriazole. This is showcased in the synthesis of several photoswitchable conjugates, with potential applications as photoPROTACs and biotin conjugates.
- Anderl, Felix,Balkenhohl, Moritz,Carreira, Erick M.,Fink, Moritz,Pfaff, Patrick
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supporting information
p. 14495 - 14501
(2021/09/18)
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- Thiofunctionalization of Electron-Rich Heteroarenes through Magnesiation and Trapping with Octasulfur
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Herein we report a site-selective and thiol-free thiofunctionalization of electron-rich heteroarenes. After a selective ortho-magnesiation, the use of S8 followed by an electrophile allows direct access to S-alkyl or -aryl derivatives. In situ oxidation provides the corresponding sulfoxide and sulfone derivatives. Applying this protocol, Cerlapirdine was prepared in 4 steps with 28% overall yield. (Figure presented.).
- Vera, Gonzalo,Mangeant, Reynald,Stiebing, Silvia,Berhault, Yohann,Fabis, Frédéric,Cailly, Thomas,Collot, Valérie
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supporting information
p. 5099 - 5105
(2021/09/25)
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- Metal-Free Visible-Light Synthesis of Arylsulfonyl Fluorides: Scope and Mechanism
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The first metal-free procedure for the synthesis of arylsulfonyl fluorides is reported. Under organo-photoredox conditions, aryl diazonium salts react with a readily available SO2 source (DABSO) to afford the desired product through simple nucleophilic fluorination. The reaction tolerates the presence of both electron-rich and -poor aryls and demonstrated a broad functional group tolerance. To shed the light on the reaction mechanism, several experimental techniques were combined, including fluorescence, NMR, and EPR spectroscopy as well as DFT calculations.
- Louvel, Dan,Chelagha, Aida,Rouillon, Jean,Payard, Pierre-Adrien,Khrouz, Lhoussain,Monnereau, Cyrille,Tlili, Anis
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supporting information
p. 8704 - 8708
(2021/05/17)
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- Aryl Radical Activation of C-O Bonds: Copper-Catalyzed Deoxygenative Difluoromethylation of Alcohols
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Given their ubiquity in natural products and pharmaceuticals, alcohols represent one of the most attractive starting materials for the construction of C-C bonds. We report herein the first catalytic strategy to harness the reactivity of aryl radicals for the activation of C-O bonds in alcohol-derived xanthate esters, allowing for the discovery of the first catalytic deoxygenative difluoromethylation reaction. Under copper-catalyzed conditions, a wide variety of alkyl xanthate esters, readily synthesized from alcohol feedstocks, were activated by catalytically generated aryl radicals and were converted to the alkyl-difluoromethane products via alkyl radical intermediates. This scalable protocol exhibits a broad substrate scope and functional group tolerance, enabling late-stage modification of complex pharmaceutical agents. A one-pot protocol has been developed that allows for the direct use of free alcohols without purification of the xanthate esters. Mechanistic studies are consistent with the hypothesis of aryl radicals being formed and initiating the cleavage of the C-O bonds of xanthate esters, to generate alkyl radicals as the key intermediates. This aryl radical activation approach represents a new strategy for the activation of alcohols as cross-coupling partners.
- Cai, Aijie,Liu, Wei,Yan, Wenhao
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supporting information
p. 9952 - 9960
(2021/07/21)
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- PYRAZOLOTRIAZOLOPYRIMIDINE DERIVATIVES AS A2A RECEPTOR ANTAGONIST
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Disclosed herein is a pyrazolotriazolopyrimidine derivative or a stereoisomer thereof, or a pharmaceutically acceptable salt thereof useful as A2A receptor antagonist, and a pharmaceutical composition comprising the same. Also disclosed herein is a method of treating cancer using the pyrazolotriazolopyrimidine derivative or a stereoisomer thereof, or a pharmaceutically acceptable salt thereof as A2A receptor antagonist.
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Paragraph 0778-0780
(2020/02/16)
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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supporting information
p. 1812 - 1819
(2020/03/17)
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- RhIII-Catalyzed Synthesis of Highly Substituted 2-Pyridones using Fluorinated Diazomalonate
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A RhIII-catalyzed strategy was developed for the rapid construction of highly substituted 2-pyridone scaffolds using α,β-unsaturated oximes and fluorinated diazomalonate. The reaction proceeds through direct, site-selective alkylation based on migratory insertion and subsequent cyclocondensation. A wide substrate scope with different functional groups was explored. The requirement of fluorinated diazomalonate was explored for this transformation. The developed methodology was further extended with the synthesis of the bioactive compound.
- Das, Debapratim,Sahoo, Gopal,Biswas, Aniruddha,Samanta, Rajarshi
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supporting information
p. 360 - 364
(2020/01/25)
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- Dual palladium-photoredox catalyzed chemoselective C-H arylation of phenylureas
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A highly chemoselective C-H arylation of phenylureas has been accomplished using dual palladium-photoredox catalysis at room temperature without any additives, base or external oxidants. Regioselective C-H arylation ofN,N'-diaryl substituted unsymmetrical phenylureas has also been accomplished by a careful choice of aryl groups.
- Babu, Sakamuri Sarath,Shahid,Gopinath, Purushothaman
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supporting information
p. 5985 - 5988
(2020/06/04)
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- Visible-Light-Mediated Ru-Catalyzed Synthesis of 3-(Arylsulfonyl)but-3-enals via Coupling of α-Allenols with Diazonium Salts and Sulfur Dioxide
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The first coupling of α-allenols, sulfur dioxide, and arenediazonium salts is presented. The three-component reaction which is promoted by visible light can be easily accomplished using DABSO as a sulfur dioxide surrogate in the presence of a photoredox catalyst. In this manner, a broad range of electron-rich and electron-deficient aryl substituents are well accommodated in the sulfonylation-rearrangement cascade to afford the 2,2-disubstituted 3-(arylsulfonyl)but-3-enals in reasonable yields. Based on control experiments, a radical mechanism which does imply 1,2-aryl migration has been proposed.
- Herrera, Fernando,Luna, Amparo,Almendros, Pedro
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supporting information
p. 9490 - 9494
(2020/12/21)
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- Transition-Metal- A nd Light-Free Directed Amination of Remote Unactivated C(sp3)-H Bonds of Alcohols
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Due to the great value of amino alcohols, new methods for their synthesis are in high demand. Abundant aliphatic alcohols represent the ideal feedstock for the method development toward this important motif. To date, transition-metal-catalyzed approaches for the directed remote amination of alcohols have been well established. Yet, they have certain disadvantages such as the use of expensive catalysts and limited scope. Very recently, transition-metal-free visible-light-induced radical approaches have emerged as new powerful tools for directed remote amination of alcohols. Relying on 1,5-HAT reactivity, these methods are limited to β-or δ- A mination only. Herein, we report a novel transitionmetal- A nd visible-light-free room-temperature radical approach for remote β-, γ-, and δ-C(sp3)-N bond formation in aliphatic alcohols using mild basic conditions and readily available diazonium salt reagents.
- Kurandina, Daria,Yadagiri, Dongari,Rivas, Monica,Kavun, Aleksei,Chuentragool, Padon,Hayama, Keiichi,Gevorgyan, Vladimir
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supporting information
p. 8104 - 8109
(2019/06/13)
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- Gold(I)-Catalyzed Cross-Coupling Reactions of Arenediazonium Salts with Alkynoic Acids
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Abstract: The reaction of simple alkynoate salts with isolated arenediazonium tetrafluoroborate salts that had been pre-conditioned with the gold(I) catalyst AuCl(Me2S) led to the formation of cross-coupled products via a decarboxylative Sonogashira reaction process in modest yield and under mild conditions. The major by-product is a defunctionalized aryl moiety stemming from the diazonium salt, which competitively forms via hydrodediazonation. Good functional group tolerance and reaction site selectivity were attained in this limited investigation.
- Abrams, J. N.,Chi, B. K.
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p. 1236 - 1244
(2020/09/17)
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- Rational Design of Azothiophenes—Substitution Effects on the Switching Properties
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A series of substituted azothiophenes was prepared and investigated toward their isomerization behavior. Compared to azobenzene (AB), the presented compounds showed red-shifted absorption and almost quantitative photoisomerization to their (Z) states. Furthermore, it was found that electron-withdrawing substitution on the phenyl moiety increases, while electron-donating substitution decreases the thermal half-lives of the (Z)-isomers due to higher or lower stabilization by a lone pair–π interaction. Additionally, computational analysis of the isomerization revealed that a pure singlet state transition state is unlikely in azothiophenes. A pathway via intersystem crossing to a triplet energy surface of lower energy than the singlet surface provided a better fit with experimental data of the (Z)→(E) isomerization. The insights gained in this study provide the necessary guidelines to design effective thiophenylazo-photoswitches for applications in photopharmacology, material sciences, or solar energy harvesting applications.
- Heindl, Andreas H.,Wegner, Hermann A.
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supporting information
p. 13730 - 13737
(2020/10/02)
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- Comparison of the Thermal Stabilities of Diazonium Salts and Their Corresponding Triazenes
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A range of diazonium salts and their corresponding triazenes have been prepared in order to directly compare their relative thermal stabilities (via initial decomposition temperature) from differential scanning calorimetry (DSC) data. A structure-stability relationship has been explored to investigate trends in stability, depending on the aromatic substituent and the structure of the secondary amine component of the diazonium salts and triazenes. All of the triazenes investigated show significantly greater stability (many are stable above 200 °C) compared with the corresponding diazonium salts, which show varying stabilities.
- Schotten, Christiane,Leprevost, Samy K.,Yong, Low Ming,Hughes, Colan E.,Harris, Kenneth D. M.,Browne, Duncan L.
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supporting information
p. 2336 - 2341
(2020/06/05)
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- Copper-mediated tandem ring-opening/cyclization reactions of cyclopropanols with aryldiazonium salts: Synthesis of: N -arylpyrazoles
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A general method for the synthesis of structurally diverse N-arylpyrazoles from readily available cyclopropanols and aryldiazonium salts is disclosed. The reaction was conducted at room temperature within minutes with a broad substrate scope and excellent regioselectivity.
- Liu, Jidan,Xu, Erjie,Jiang, Jinyuan,Huang, Zeng,Zheng, Liyao,Liu, Zhao-Qing
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supporting information
p. 2202 - 2205
(2020/02/26)
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- Method for synthesis of phenylhydrazine from diazonium salt
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The invention provides a method for synthesis of phenylhydrazine from a diazonium salt. The method includes: A) diazotizing aniline to obtain diazobenzene; B) carrying out reduction reaction on diazobenzene and organophosphorus to obtain a first intermediate; and C) subjecting the first intermediate to heating reflux acidification reaction in the presence of an organic solvent and acid to obtain phenylhydrazine. The method provided by the invention adopts electron-rich organphosphorus as the reducing agent to reduce the diazonium salt, and has the advantages of no generation of salt wastewater and recycling of unreacted organophosphorus and oxidized organophosphorus into products with economic benefits. The synthesis of phenylhydrazine needs three steps in total, thus simplifying the complex operation procedure in industry. To sum up, compared with the prior art, the method provided by the invention has better industrialization application prospects.
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Paragraph 0048; 0049
(2019/10/04)
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- Additions to N-Sulfinylamines as an Approach for the Metal-free Synthesis of Sulfonimidamides: O-Benzotriazolyl Sulfonimidates as Activated Intermediates
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Sulfonimidamides are obtained in moderate to very good yields from the key intermediates O-benzotriazolyl sulfonimidates, which are formed by reacting aryldiazonium tetrafluoroborates, N-tritylsulfinylamine, and N-hydroxybenzotriazole hydrate in a process mediated by a tertiary amine. The formation of the sulfonimidate proceeds in inexpensive and environmentally benign dimethyl carbonate as the solvent, it does not require anhydrous conditions, and the product yields generally exceed 70 %. The substrate scope is broad, and a wide range of sensitive organic functionalities is well tolerated. The reactions probably proceed via aryl radicals formed from diazonium cations with assistance from both the tertiary amine and the sulfinylamine.
- Bremerich, Maximilian,Conrads, Christian M.,Langletz, Tim,Bolm, Carsten
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supporting information
p. 19014 - 19020
(2019/11/22)
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- Light-Induced Mechanistic Divergence in Gold(I) Catalysis: Revisiting the Reactivity of Diazonium Salts
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In a systematic study of the Au-catalyzed reaction of o-alkynylphenols with aryldiazonium salts, we find that essentially the same reaction conditions lead to a change in mechanism when a light source is applied. If the reaction is carried out at room temperature using a AuI catalyst, the diazonium salt undergoes electrophilic deauration of a vinyl AuI intermediate and provides access to substituted azobenzofurans. If the reaction mixture is irradiated with blue LED light, C?C bond formation due to N2-extrusion from the diazonium salt is realized selectively, using the same starting materials without the need for an additional photo(redox) catalyst under aerobic conditions. We report a series of experiments demonstrating that the same vinyl AuI intermediate is capable of producing the observed products under photolytic and thermal conditions. The finding that a vinyl AuI complex can directly, without the need for an additional photo(redox) catalyst, result in C?C bond formation under photolytic conditions is contrary to the proposed mechanistic pathways suggested in the literature till date and highlights that the role of oxidation state changes in photoredox catalysis involving Au is thus far only poorly understood and may hold surprises for the future. Computational results indicate that photochemical activation can occur directly from a donor–acceptor complex formed between the vinyl AuI intermediate and the diazonium salt.
- Taschinski, Svenja,D?pp, René,Ackermann, Martin,Rominger, Frank,de Vries, Folkert,Menger, Maximilian F. S. J.,Rudolph, Matthias,Hashmi, A. Stephen K.,Klein, Johannes E. M. N.
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supporting information
p. 16988 - 16993
(2019/11/13)
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- Generation of 1,3-Dimethylene-Substituted Isobenzofurans via Pd(II)-Catalyzed Selective Oxo-cyclization/SO2 Insertion Cascade of β-Alkynyl Ketones
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A new palladium(II)-catalyzed cyclization-radical addition cascade enables the direct construction of 1,3-dimethylene-substituted isobenzofuran derivatives containing a vinyl aryl sulfone unit in good yields by treating with β-alkynyl ketones, aryl diazonium salts, and DABCO·(SO2)2. The oxidant-free multicomponent reaction features good substrate scope and functional group tolerance, which proceeds through a sequence of Heck coupling, oxo-cyclization, and SO2 insertion.
- Liu, Shuai,Chen, Ke,Hao, Wen-Juan,Tu, Xing-Chao,Tu, Shu-Jiang,Jiang, Bo
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p. 1964 - 1971
(2019/05/16)
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- Copper(I)-promoted trifluoromethylthiolation of arenediazonium salts with AgSCF3
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An efficient method for trifluoromethylthiolation of arenediazonium salts has been developed in mild conditions with a stable and convenient AgSCF3. It provides a straightforward and convenient way for the synthesis of trifluoromethylthiolated compound from diazonium salts in moderate to good yields.
- Zheng, Changge,Liu, Yang,Hong, Jianquan,Huang, Shuai,Zhang, Wei,Yang, Yupeng,Fang, Ge
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supporting information
p. 1404 - 1407
(2019/05/01)
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- Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
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Main group metal based catalysis has been considered to be a cost-effective alternative way to the transition metal based catalysis, due to the high abundance of main group metals in the Earth's crust. Among the main group metals, aluminum is the most abundant (7-8%) in the Earth's crust, making the development of aluminum based catalysts very attractive. So far, aluminum based compounds have been popularly used as Lewis acids in a variety of organic reactions, but chemical transformation demanding a redox based process has never utilized an Al(III) complex as a catalyst. Herein, we tuned the redox noninnocence behavior of a phenalenyl ligand by coupling with Al(III) ion, which subsequently can store the electron upon reduction with K to carry out direct C-H arylation of heteroarenes/mesitylene at ambient temperature. A mechanistic investigation revealed that a three-electron reduced phenalenyl based triradical aluminum(III) complex plays the key role in such catalysis. The electronic structure of the catalytically active triradical species has been probed using EPR spectroscopy, magnetic susceptibility measurements, and electronic structure calculations using a DFT method.
- Vardhanapu, Pavan K.,Ahmed, Jasimuddin,Jose, Anex,Shaw, Bikash Kumar,Sen, Tamal K.,Mathews, Amita A.,Mandal, Swadhin K.
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p. 289 - 299
(2019/01/10)
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- Preparation of N-Arylquinazolinium Salts via a Cascade Approach
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An easy manipulation method for the preparation of N-arylquinazolinium salts is described from readily available aryldiazonium salts, nitriles, and 2-aminoarylketones in a one-pot operation. This method relies on the in situ generation of the N-arylnitrilium intermediate from the reaction of aryldiazonium salt with nitrile, which undergoes amination/cascade cyclization/aromatization, leading to N-arylquinazolinium salts in excellent yields. Nucleophilic addition of alkoxide to these N-arylquinazolinium salts provides functionalized dihydro-N-arylquinazoline.
- Ramanathan, Mani,Wan, Jing,Liu, Shiuh-Tzung
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p. 7459 - 7467
(2019/06/14)
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- Photocatalyzed borylation using water-soluble quantum dots
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The synthesis of arylboronates by Sandmeyer-type reactions in the presence of water still remains a significant challenge. Herein, we report the use of water-soluble MPA-capped quantum dot (QD) photocatalysts for the borylation of diazonium salts in the presence of water. A biphasic system under mild acidic conditions remains critical to prevent decomposition and competitive disulphide bond formation. The present protocol offers a broader scope of substrates and borylating agents. Additionally, this catalytic system offers a significantly high turnover number (TON). The present methodology can effectively distinguish subtle reactivity differences between boronic acids and boronates. Mechanistic investigation suggests an excited-state electron transfer pathway.
- Chandrashekar, Hediyala B.,Maji, Arun,Halder, Ganga,Banerjee, Sucheta,Bhattacharyya, Sayan,Maiti, Debabrata
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supporting information
p. 6201 - 6204
(2019/06/07)
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- Electrochemical Cross-Coupling of C(sp2)?H with Aryldiazonium Salts via a Paired Electrolysis: an Alternative to Visible Light Photoredox-Based Approach
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Photoredox-based C?H bond functionalization constitutes one of the most powerful and atom-economical approaches to organic syntheses. During this type of reaction, single electron transfer takes place between the photocatalyst (PC) and redox- active substrates. Electrosynthesis also involves electron transfer between substrates and electrodes. In this paper, we focus upon electrochemical cross-coupling of C(sp2)?H with aryldiazonium salts and have developed an efficient electrochemical approach to the Minisci-type arylation reaction. The constant current paired electrosynthesis proceeds in a simple undivided cell without external supporting electrolyte, features a wide range of substrates and is easy to scale-up. These results demonstrate that photoredox-based cross-coupling of C(sp2)?H with aryldiazonium salts can also proceed successfully under paired electrolysis conditions, thereby contributing to understanding of the parallels between photosynthesis and electrosynthesis. (Figure presented.).
- Jiang, Yang-ye,Dou, Gui-yuan,Zhang, Luo-sha,Xu, Kun,Little, R. Daniel,Zeng, Cheng-chu
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supporting information
p. 5170 - 5175
(2019/11/13)
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- A six-amino acid salt synthesis method (by machine translation)
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The embodiment of the invention provides a six-amino acid salt synthesis method. The method comprises: shown in formula I 1, 3, 5 - three amino as reaction raw material, under the alkaline condition is shown with the structural formula III coupling reaction of the diazonium salt, filtering and drying process as shown in the structural formula IV obtained after six-substituted P-amino; Reducing the micromotion substituted P-composition, adding hydrochloric acid reagent, prepared as shown in the structural formula V six amino hydrochloride. The present invention provides synthetic method has simple process, raw material sources are extensive, low cost of raw materials, the reaction speed is fast, high yield, the product is easy to separation and purification and the like. (by machine translation)
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Paragraph 0105; 0106-0111
(2019/01/14)
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- Palladium catalyzed stereocontrolled synthesis of C-aryl glycosides using glycals and arenediazonium salts at room temperature
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A stereocontrolled synthesis of aryl-C-glycosides was achieved using glycals and aryldiazonium salts in the presence of palladium acetate. A wide range of glycals including d-glucal, d-galactal, l-rhamnal, d-xylal and d-ribal underwent C-arylation at the anomeric carbon in the presence of different aryldiazonium tetrafluoroborates and gave synthetically useful 2,3-deoxy-3-keto-α-aryl-C-glycosides in good to excellent yields. Broad substrate scope, simple operation and room temperature reactions make this protocol very attractive in organic synthesis.
- Singh, Adesh Kumar,Kandasamy, Jeyakumar
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supporting information
p. 5107 - 5112
(2018/07/29)
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- Synthesis of Chiral Sulfonyl Lactones via Copper-Catalyzed Asymmetric Radical Reaction of DABCO?(SO2)
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In the present work, an asymmetric copper-catalyzed radical multi-component cascade reaction of an unsaturated carboxylic acid, aryldiazonium tetrafluoroborate, and DABCO?(SO2)2 (DABSO) has been developed for the enantioselective synthesis of sulfonyl lactones. In this reaction, this SO2 surrogate, DABSO was applied for the first time in the construction of chiral compounds. This multiple-step asymmetric radical reaction was carried out under mild conditions and tolerated a wide range of substrates, resulting in the corresponding sulfonyl lactones with up to 95% chemical yields and 88% ee. The current reaction enriches the research contents of DABSO, and provides a new and efficient strategy to chiral functionalized lactones bearing quarternary stereogenic center. (Figure presented.).
- Wang, Yang,Deng, Lingling,Zhou, Jie,Wang, Xiaochen,Mei, Haibo,Han, Jianlin,Pan, Yi
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supporting information
p. 1060 - 1065
(2018/01/22)
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- GOLD-CATALYZED C-C CROSS-COUPLING OF BORON- AND SILICON-CONTAINING ARYL COMPOUNDS AND ARYLDIAZONIUM COMPOUNDS BY VISIBLE-LIGHT
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The present invention relates to a method for producing (functionalized) biaryls by employing a visible-light-driven, gold-catalyzed C-C cross-coupling reaction system involving boron- and silicon-containing aryl compounds and aryldiazonium compounds. Moreover, the present invention relates to the use of such boron- and silicon-containing aryl compounds and aryldiazonium compounds, as well as related gold catalysts, in the manufacture of (functionalized) biaryls.
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Page/Page column 23; 24
(2018/07/29)
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- Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
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An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions (25–60 °C), and features a wide substrate scope and good functional-group compatibility.
- Xing, Bo,Ni, Chuanfa,Hu, Jinbo
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supporting information
p. 9896 - 9900
(2018/07/31)
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- Practical Reagents and Methods for Nucleophilic and Electrophilic Phosphorothiolations
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New late-stage phosphorothiolation methods are disclosed that allow the efficient transfer of SP(O)(OR)2 groups to diversely functionalized substrates using nucleophilic and electrophilic reagents. The nucleophilic reagent, tetramethylammonium O,O-dimethyl phosphorothioate, was synthesized in near-quantitative yield from Me3SiP(O)(OMe)2, elemental sulfur and Me4NF. Its umpolung with N-bromophthalimide provided the electrophilic reagent, O,O-dimethyl-S-(N-phthalimido)phosphorothioate. Complementary methods based on these reagents enable the phosphorothiolation of diversely functionalized alkyl halides, arenediazonium salts, arylboronic acids and electron-rich arenes in good yields under mild conditions. (Figure presented.).
- Kovács, Szabolcs,Bayarmagnai, Bilguun,Aillerie, Alexandre,Goo?en, Lukas J.
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supporting information
p. 1913 - 1918
(2018/03/30)
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- An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
- Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
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supporting information
p. 17651 - 17655
(2018/11/10)
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- Visible-Light-Mediated Hydroxycarbonylation of Diazonium Salts
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A visible light-promoted catalytic photoredox hydroxycarbonylation was achieved on aryl diazonium salts whether preformed or generated in situ from the corresponding anilines. This strategy allows a straightforward access to a variety of carboxylic acids under mild conditions. (Figure presented.).
- Gosset, Cyrille,Pellegrini, Sylvain,Jooris, Romain,Bousquet, Till,Pelinski, Lydie
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supporting information
p. 3401 - 3405
(2018/08/06)
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- Preparation method of 1,3-dimethyl-5-phenyluracil
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The invention relates to a preparation method of 1,3-dimethyl-5-phenyluracil. The preparation method includes mixing phenylamine, water and a fluoboric acid water solution, dropwise adding a water solution of sodium nitrite with stirring for 1-2 hours at 0-5 DEG C and performing suction filtration so as to obtain phenyldiazonium tetrafluoroborate; at the room temperature, adding 1,3-dimethyluracil and a copper salt catalyst into a solvent with stirring and mixing, adding the phenyldiazonium tetrafluoroborate in batches, stirring to react for 8-12 hours after addition is finished, and conducting separation and purification so as to obtain the 1,3-dimethyl-5-phenyluracil. The preparation method has the advantages of simplicity in operation, short reaction route, less reaction time, high product yield and suitability for industrialized production.
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Paragraph 0040; 0041
(2017/07/01)
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- Palladium-Nanoparticles-Catalyzed Oxidative Annulation of Benzamides with Alkynes for the Synthesis of Isoquinolones
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A novel method to synthesize isoquinolones via oxidative annulation of N-alkoxy benzamides and alkynes using binaphthyl-stabilized palladium nanoparticles (Pd-BNP) as catalyst has been developed. This methodology affords various isoquinolone derivatives in good to excellent yields with high regioselectivities in the presence of air as oxidant. N-Methoxybenzothioamide was also found to undergo oxidative annulation with alkyne successfully and provided a sulfur analogue of isoquinolones in moderate yields. The Pd-BNP catalyst was easily recovered and reused up to four times without any apparent agglomeration. (Figure presented.).
- Sharma, Nidhi,Saha, Rajib,Parveen, Naziya,Sekar, Govindasamy
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supporting information
p. 1947 - 1958
(2017/06/09)
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- Efficient copper-catalyzed N-arylation of NH-containing heterocycles and sulfonamides with arenediazonium tetrafluoroborates
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A practical copper-catalyzed N-arylation of NH-containing heterocycles with arenediazonium tetrafluoroborates has been developed using CuCl as catalyst and K2CO3 as additive under ligand-free conditions. This reaction system has wide substrate scope including imides, 1H-pyrazole, 1H-tetrazoles, 1,2-benzisothiazol-3(2H)-one, and related sulfonamides and gives moderate to excellent yields (up to 95%) of the desired products. This strategy is very general, simple, environmentally friendly, and tolerant of oxygen.
- Ouyang, Yu-Qing,Yang, Zhen-Hua,Chen, Zhong-Hui,Zhao, Sheng-Yin
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supporting information
p. 771 - 778
(2017/04/06)
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- Photoredox Catalysis Induced Bisindolylation of Ethers/Alcohols via Sequential C-H and C-O Bond Cleavage
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A visible-light-engaged 2-fold site-selective alkylation of indole derivatives with aliphatic ethers or alcohols has been accomplished for easy access to symmetric 3,3′-bisindolylmethane derivatives. The experimental data suggest a sequential photoredox catalysis induced radical addition and proton-mediated Friedel-Crafts alkylation mechanism.
- Ye, Lu,Cai, Sai-Hu,Wang, Ding-Xing,Wang, Yi-Qiu,Lai, Lin-Jie,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 6164 - 6167
(2017/11/24)
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- Copper-Catalyzed Arylsulfonylation and Cyclizative Carbonation of N-(Arylsulfonyl)acrylamides Involving Desulfonative Arrangement toward Sulfonated Oxindoles
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Sulfonated oxindoles are accessed by a Cu(OAc)2-catalyzed three-component reaction of N-(arylsulfonyl)acrylamides, DABSO, and aryldiazonium tetrafluoroborates. This transformation is triggered by the formation of arylsulfonyl radicals in situ from the reaction of aryldiazonium tetrafluoroborates and DABSO. Afterward, the sequential radical addition, radical cyclization, and desulfonylative 1,4-aryl migration take place to provide the final product by the formation of four new bonds in one pot. This procedure shows good functional group tolerance.
- Wang, Hepan,Sun, Song,Cheng, Jiang
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supporting information
p. 5844 - 5847
(2017/11/10)
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- Erythrosine B Catalyzed Visible-Light Photoredox Arylation–Cyclization of N-Alkyl-N-aryl-2-(trifluoromethyl)acrylamides to 3-(Trifluoromethyl)indolin-2-one Derivatives
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3-Trifluoromethylindoline-2-one derivatives were prepared in a visible-light photocatalytic transformation of acrylamides. The arylation–cyclization sequence was initiated by light-induced aryl radical generation from aryldiazonium salts with the utilization of erythrosine B as an organic photocatalyst.
- Gonda, Zsombor,Béke, Ferenc,Tischler, Orsolya,Petró, Milán,Novák, Zoltán,Tóth, Balázs L.
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supporting information
p. 2112 - 2117
(2017/04/24)
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- Cascade annulations of aryldiazonium salts, nitriles and halo-alkynes leading to 3-haloquinolines
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A regiospecific access to 3-haloquinolines has been developed via a three-component annulation of aryldiazonium salts, nitriles and haloalkynes. This reaction proceeds through an initial formation of reactive nitrilium ion and further cascade annulation with haloalkynes. This method provides a straightforward access to a diverse array of functionalized quinolones (28 examples) under mild conditions and exhibits broad functional group tolerance. Applications of this method in a gram scale reaction and a formal synthesis of Pitavastatin are illustrated.
- Ramanathan, Mani,Liu, Shiuh-Tzung
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p. 4317 - 4322
(2017/06/30)
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- Visible-Light-Promoted C-H Arylation by Merging Palladium Catalysis with Organic Photoredox Catalysis
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The use of a dual palladium/organic photoredox catalytic system enables the directed arylation of arenes with aryldiazonium salts with a broad substrate scope at room temperature under mild reaction conditions. This study thus serves as not only an alternative route for the biaryl motifs but also a new example for the application of an organic photoredox catalyst.
- Jiang, Jian,Zhang, Wen-Man,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
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p. 3622 - 3630
(2017/04/11)
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- Tandem and chemoselective synthesis of benzil derivatives from styrene and arene diazonium salts
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A facile and practically applied protocol for synthesis of benzil derivatives using styrene and arene diazonium salts is reported. Pd(OAc)2/SeO2 catalytic system was found to be efficient for chemoselective synthesis of benzil. Selenium dioxide works well as an oxidant under milder reaction conditions. Moderate to very good yields of the desired products were obtained.
- Jadhav, Vilas G.,Sarode, Sachin A.,Nagarkar, Jayashree M.
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supporting information
p. 1834 - 1838
(2017/04/21)
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- Visible-Light-Mediated Monoselective Ortho C-H Arylation of 6-Arylpurine Nucleosides with Diazonium Salts
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A combined palladium- and photoredox-catalyzed monoselective arylation of 6-arylpurine nucleosides has been developed by employing purine as a directing group via the photoredox reaction, and many functional groups are well tolerated in this direct C-H arylation condition. Various of functionalized purines (nucleosides) which are potentially of great importance in medicinal chemistry could be obtained under visible light irradiation at room temperature within 4 h.
- Liang, Lei,Xie, Ming-Sheng,Wang, Hai-Xia,Niu, Hong-Ying,Qu, Gui-Rong,Guo, Hai-Ming
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p. 5966 - 5973
(2017/06/07)
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- Detecting targets using mass tags and mass spectrometry
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Particular disclosed embodiments disclosed herein concern using a one or more various mass tags, which can be specifically deposited at targets through direct or indirect enzymatic-catalyzed transformation, to provide a method for identifying targets in tissue samples. The mass tags may be labeled with stable isotopes to produce mass tags having the same chemical structure but different masses. Mass codes produced by ionizing the mass tags are detected and/or quantified using mass spectrometry. The method can be used for multiplexed detection of multiple targets in a particular sample. In some embodiments, a map divided into sections representing sections of the tissue sample may be prepared, with the map sections including data corresponding to quantification data wherein the size of a mass peak is determined and correlated with the amount of a target for the corresponding tissue sample section.
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Page/Page column 143-144
(2016/04/20)
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- Photosensitizer-Free Visible-Light-Mediated Gold-Catalyzed 1,2-Difunctionalization of Alkynes
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Under visible-light irradiation, the gold-catalyzed intermolecular difunctionalization of alkynes with aryl diazonium salts in methanol affords a variety of α-aryl ketones in moderate to good yields. In contrast to previous reports on gold-catalyzed reactions that involve redox cycles, no external oxidants or photosensitizers are required. The reaction proceeds smoothly under mild reaction conditions and shows broad functional-group tolerance. Further applications of this method demonstrate the general applicability of the arylation of a vinyl gold intermediate instead of the commonly used protodemetalation step. This step provides facile access to functionalized products in one-pot processes. With a P,N-bidentate ligand, a stable aryl gold(III) species was obtained, which constitutes the first direct experimental evidence for the commonly postulated direct oxidative addition of an aryl diazonium salt to a pyridine phosphine gold(I) complex.
- Huang, Long,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 4808 - 4813
(2016/04/19)
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- Ferrocene catalysed C–H arylation of arenes and reaction mechanism study using cyclic voltammetry
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Ferrocene catalysed C–H arylation of benzene using aryldiazonium salt is studied. Yield of biphenyl in this reaction was found to be better than some of the known methods. Aryldiazonium salts with electron withdrawing groups produced excellent yields (upto 85%) in C–H arylation. Applicability of this reaction was studied on several arenes and heteroarene such as benzene, naphthalene, anthracene, pyrene and pyridine. Catalytic role of ferrocene in aryl radical formation was studied by cyclic voltammetry of phenyldiazonium tetrafluoroborate. In presence of ferrocene more radical formation was observed. This reaction model works at ambient temperature and features the use of inexpensive catalyst for the synthesis of biaryl derivatives.
- Dixit, Swati,Siddiqui, Qamar Tabrez,Muneer, Mohammad,Agarwal, Neeraj
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p. 4228 - 4231
(2016/08/25)
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- Synthesis of 2-aryl-2H-tetrazoles via a regioselective [3+2] cycloaddition reaction
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A regioselective cycloaddition reaction of arenediazonium salts with trimethylsilyldiazomethane is reported. A series of 2-aryltetrazoles were obtained in good to moderate yields with wide functional group compatibility. Furthermore, this cycloaddition reaction opens the way to build up the versatile intermediate 2-aryl-5-bromotetrazole.
- Patouret, Remi,Kamenecka, Theodore M.
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supporting information
p. 1597 - 1599
(2018/03/28)
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- An unprecedentedly simple method of synthesis of aryl azides and 3-hydroxytriazenes
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Fischer's approach towards the synthesis of aryl azides and triazinoles from diazonium salts and hydroxylammonium chloride (phenylhydraxylamine) was reinvestigated and optimized. The new methodology enables the preparation of aryl azides and triazinoles in high yields in water at room temperature. The procedure is very simple, robust, easily scalable, reproducible, and "green".
- Gribanov, Pavel S.,Topchiy, Maxim A.,Golenko, Yulia D.,Lichtenstein, Yana I.,Eshtukov, Artur V.,Terekhov, Vladimir E.,Asachenko, Andrey F.,Nechaev, Mikhail S.
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supporting information
p. 5984 - 5988
(2018/06/06)
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- Preparation method of 2-phenyl-1,1-dioxo-1,2-benzisothiazole-3(2H)-one
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The invention relates to a preparation method of 2-phenyl-1,1-dioxo-1,2-benzisothiazole-3(2H)-one. The preparation method comprises the following steps: (1) mixing aniline, water and a fluoboric acid aqueous solution, then dropwise adding a sodium nitrite aqueous solution while stirring at the temperature of 0-5 DEG C, heating to room temperature after dropwise adding is finished, continuing stirring and reacting for 1-2 hours, and carrying out suction filtration to obtain benzenediazonium tetrafluoroborate; (2) stirring and mixing 1,1-dioxo-1,2-benzisothiazole-3(2H)-one, alkali, a copper salt catalyst and a solvent at the temperature from minus 5 DEG C to 5 DEG C, then adding the benzenediazonium tetrafluoroborate in batches, reacting for 6-8 hours while stirring at the temperature from minus 5 DEG C to room temperature, and after reaction is finished, extracting, drying, removing the solvent by evaporation, and carrying out recrystallization to obtain the final product. The copper salt is used as the catalyst, so that reaction time is shortened, and meanwhile, yield is improved; the starting material of the preparation method is easy to obtain, the cost is low, reaction operation is simple, a reaction path is short, industrial production is facilitated, and the application prospect is good.
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Paragraph 0023; 0037; 0038
(2017/01/12)
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- The triple-bond metathesis of aryldiazonium salts: A prospect for dinitrogen cleavage
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The {N2} unit of aryldiazonium salts undergoes unusually facile triple-bond metathesis on treatment with molybdenum or tungsten alkylidyne ate complexes endowed with triphenylsilanolate ligands. The reaction transforms the alkylidyne unit into a nitrile and the aryldiazonium entity into an imido ligand on the metal center, as unambiguously confirmed by X-ray structure analysis of two representative examples. A tungsten nitride ate complex is shown to react analogously. Since the bonding situation of an aryldiazonium salt is similar to that of metal complexes with end-on-bound dinitrogen, in which {N2}→M σ donation is dominant and electron back donation minimal, the metathesis described herein is thought to be a conceptually novel strategy toward dinitrogen cleavage devoid of any redox steps and, therefore, orthogonal to the established methods. Who knows? Although the extrusion of molecular nitrogen from aryldiazonium salts is extremely facile, the metathetic cleavage of the N-N triple bond on treatment with alkylidyne ate complexes of molybdenum or tungsten is shown to be even faster. The analogy between [Ar-N2]+ and known [M-N2] complexes makes this process a potential model for dinitrogen cleavage devoid of any redox steps.
- Lackner, Aaron D.,Fürstner, Alois
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supporting information
p. 12814 - 12818
(2015/10/28)
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