- Direct cyanation of picolinamides using K4[Fe(CN)6] as the cyanide source
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The efficient, simple, and environment-friendly route of direct cyanation of picolinamides has been developed with nontoxic K4[Fe(CN)6] as the cyanide source through Pdcatalyzed C-H bond activation. A series of N-(naphthalene-1- yl)picolinamide derivatives were successfully transformed to the corresponding cyanation products. The cyanation mechanism has also been speculated.
- Guan, Dinghui,Han, Lu,Wang, Lulu,Song, He,Chu, Wenyi,Sun, Zhizhong
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- Electrochemical C-H Halogenations of Enaminones and Electron-Rich Arenes with Sodium Halide (NaX) as Halogen Source for the Synthesis of 3-Halochromones and Haloarenes
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Without employing an external oxidant, the simple synthesis of 3-halochromones and various halogenated electron-rich arenes has been realized with electrode oxidation by employing the simplest sodium halide (NaX, X = Cl, Br, I) as halogen source. This electrochemical method is advantageous for the simple and mild room temperature operation, environmental friendliness as well as broad substrate scope in both C-H bond donor and halogen source components.
- Jin, Jun,Lin, Yan,Liu, Yunyun,Wan, Jie-Ping,Wang, Chaoli
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p. 12378 - 12385
(2021/09/07)
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- Mild and Selective Method of Bromination of Flavonoids
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A new method was developed for the mild and selective bromination of simple aromatic compounds and flavonoids in good yields using α,β-dibromohydrocinnamic acid in the presence of a base. This procedure enables selective mono- or dibromination of compounds highly sensitive to oxidative or radical attack. New brominated derivatives of silymarin flavonolignans and related flavonoids were prepared. These brominated derivatives can be used as valuable synthetic intermediates in further synthesis.
- Hurtová, Martina,Biedermann, David,Kuzma, Marek,K?en, Vladimír
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p. 3324 - 3331
(2020/11/30)
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- Preparation method of high-purity 1,4-dibromonaphthalene
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The invention relates to a preparation method of high-purity 1,4-dibromonaphthalene and belongs to the technical field of organic synthesis. The provided preparation method of high-purity 1,4-dibromonaphthalene aims to solve the problems that preparation methods of 1,4-dibromonaphthalene in the prior art are complicated, the reaction conditions are high, the product purity is low, the yield is low, and the product quality is unstable. The method comprises the four steps of a one-pot acetylation protection and selective bromination process, a hydrolysis deprotection process, a diazotization coupling reaction process and a recrystallization purification process to obtain high-purity 1,4-dibromonaphthalene. The provided preparation method has the advantages that the synthesis route is short,the reaction conditions are mild and easy to control, and the production cost is low. The organic synthesis reaction site is monotonous, the selectivity is high, the product purity is up to 99.0%, andthe total yield can reach 71.7%. Industrial production is easily realized, the need for large-scale production of 1,4-dibromonaphthalene can be effectively met, and the method has a broad applicationprospect.
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Page/Page column 6-12
(2019/10/01)
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- Making endo-cyclizations favorable again: A conceptually new synthetic approach to benzotriazoles via azide group directed lithiation/cyclization of 2-azidoaryl bromides
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Although benzotriazoles are important and ubiquitous, currently there is only one conceptual approach to their synthesis: bridging the two ortho-amino groups with an electrophilic nitrogen atom. Herein, we disclose a new practical alternative-the endo-cyclization of 2-azidoaryl lithiums obtained in situ from 2-azido-aryl bromides. The scope of the reaction is illustrated using twenty-four examples with a variety of alkyl, alkoxy, perfluoroalkyl, and halogen substituents. We found that the directing effect of the azide group allows selective metal-halogen exchange in aryl azides containing several bromine atoms. Furthermore, (2-bromophenyl)diazomethane undergoes similar cyclization to give an indazole. Thus, cyclizations of aryl lithiums containing an ortho-X = Y = Z group emerge as a new general approach for the synthesis of aromatic heterocycles. DFT computations suggested that the observed endo-selectivity applies to the anionic cyclizations of other functionalities that undergo "1,1-additions" (i.e., azides, diazo compounds, and isonitriles). In contrast, cyclizations with the heteroatomic functionalities that follow the "1,2-addition" pattern (cyanates, thiocyanates, isocyanates, isothiocyanates, and nitriles) prefer the exo-cyclization path. Hence, such reactions expand the current understanding of stereoelectronic factors in anionic cyclizations.
- Ageshina, Alexandra A.,Chesnokov, Gleb A.,Topchiy, Maxim A.,Alabugin, Igor V.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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supporting information
p. 4523 - 4534
(2019/05/17)
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- ANTICANCER COMPOUNDS
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The present invention discloses compounds for inhibition of uncontrolled cell proliferation particularly in cancer stem cells. Particularly, the invention relates to compounds of Formula III to XIV for the treatment of cancer, such as breast and prostate cancer.
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Page/Page column 61; 62
(2018/11/22)
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- A facile, regioselective and controllable bromination of aromatic amines using a CuBr2/Oxone system
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A combination of cupric bromide and Oxone serves as a facile, mild and effective reagent for the bromination of aromatic amines. Primary, secondary and tertiary aromatic amines are all suitable substrates. The reaction possesses high regioselectivity and functional group tolerance, and mono- and multi-brominated products can be obtained controllably in moderate to excellent yields. The Royal Society of Chemistry 2013.
- Li, Xin-Le,Wu, Wei,Fan, Xin-Heng,Yang, Lian-Ming
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p. 12091 - 12095
(2013/09/02)
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- Silica-supported quinolinium tribromide: A recoverable solid brominating reagent for regioselective monobromination of aromatic amines
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Silica-supported quinolinium tribromide was synthesized and found to be an efficient, stable, and recoverable solid brominating reagent for the regioselective monobromination of aromatic amines. This protocol has advantages of high yield, mild condition and simple work-up procedure.
- Li, Zheng,Sun, Xiunan,Wang, Lue,Li, Yanbo,Ma, Yuanhong
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scheme or table
p. 496 - 501
(2010/08/06)
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- A convenient and selective method for the para-bromination of aromatic compounds with potassium bromide in the presence of poly(4-vinylpyridine)- supported peroxodisulfate in nonaqueous solution
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A convenient and selective procedure for the para-bromination of aromatic compounds has been developed using potassium bromide in the presence of poly(4-vinylpyridine)-supported peroxodisulfate in nonaqueous solution.
- Tajik,Mohammadpoor-Baltork,Hassan-Zadeh,Rafiee Rashtabadi
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p. 1282 - 1284
(2008/03/27)
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- LEWIS ACID CATALYZED HALOGENATION OF ACTIVATED CARBON ATOMS
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A practical and efficient method for halogenation of activated carbon atoms using readily available /V-haloimides and a Lewis acid catalyst has been disclosed. This methodology is applicable to a range of compounds and any halogen atom can be directly introduced to the substrate. The mild reaction conditions, easy workup procedure and simple operation make this method valuable from both an environmental and preparative point of view.
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Page/Page column 23-26
(2008/06/13)
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- Polymer-supported organotin reagents for regioselective halogenation of aromatic amines
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(Chemical Equation Presented) Polymer-supported triorganotin halides were used in the halogenation reaction of aromatic amines. Treatment of aromatic amines with n-butyllithium and polymer-supported organotin halides gave the corresponding polymer-bound N-triorganostannylamines, which by treatment with bromine or iodine monochloride gave the para-halogenated aromatic amines with high yields and high selectivities. The polymer-supported organotin halides reagents regenerated during the course of the halogenation reaction can be reused without loss of efficiency. The presence of tin residues in halogenated aromatic amines was also investigated and evaluated at under 20 ppm after three runs.
- Chretien, Jean-Mathieu,Zammattio, Francoise,Le Grognec, Erwan,Paris, Michael,Cahingt, Blanche,Montavon, Gilles,Quintard, Jean-Paul
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p. 2870 - 2873
(2007/10/03)
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- Lewis acid catalyzed highly selective halogenation of aromatic compounds
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A simple and efficient procedure for the halogenation of aromatic compounds with NCS, NBS, NIS and NFSI in the presence of catalytic amount of ZrCl 4 is described. Chlorination, bromination, iodination and fluorination of various aromatic compounds are performed with high selectivity under mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Zhang, Yanhua,Shibatomi, Kazutaka,Yamamoto, Hisashi
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p. 2837 - 2842
(2007/10/03)
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- Regioselective synthesis of para-bromo aromatic compounds
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Reaction of substituted benzenerings with N-bromophthalimide, underneutral conditions, gave the corresponding bromo derivatives with a preference for the formation of the para bromoisomer over the ortho isomer. The sim pie work-up procedure minimizes loss of product and the yields are good.
- Khazaei, Ardeshir,Manesh, Abbas Amini,Safi, Vahid Reza
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p. 559 - 562
(2007/10/03)
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- Bromination of aromatic compounds with potassium bromide in the presence of poly(4-vinylpyridine)-supported bromate in nonaqueous solution
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A simple, efficient, and mild method for selective bromination of activated aromatic compounds using potassium bromide in the presence of poly(4-vinylpyridine)-supported bromate in nonaqueous solution is reported. The results obtained revealed excellent to good selectiveity between ortho and para positions of methoxyarenes, anilines, and phenols. Copyright Taylor & Francis, Inc.
- Tajik, Hassan,Shirini, Farhad,Hassan-Zadeh, Parwin,Rashtabadi, Hassan Rafiee
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p. 1947 - 1952
(2007/10/03)
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- [bmim]Br3 as a new reagent for regioselective monobromination of arylamines under solvent-free conditions
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Reaction of arylamines with 1-butyl-3-methylimidazolium tribromide ([bmim]Br3) under solvent-free conditions, gave selectively the corresponding monobromination products with excellent, yields.
- Le, Zhang-Gao,Chen, Zhen-Chu,Hu, Yi,Zheng, Qin-Guo
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p. 2809 - 2812
(2007/10/03)
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- A new mild regioselective bromination of arylamines
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A new efficient regioselective boron-assisted mono bromination methodology for arylamines is described. Our one-pot, three-stage approach (lithiation, boron amide formation and bromination) proved to be highly useful in mildly brominating a variety of arylamines in up to 94% yields.
- Zhao, Jingrui,Jia, Xueshun,Zhai, Hongbin
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p. 9371 - 9373
(2007/10/03)
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- Regioselective one-pot bromination of aromatic amines
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(Matrix Presented) Treatment of aniline with n-butyllithium and then trimethyltin chloride gave the tin amide (PhNH-SnMe3) in situ. Without isolation of the tin amide reaction with bromine and workup with aqueous fluoride ion gave p-bromoaniline in 76% yield, with no dibromoaniline or o-bromoaniline. Application of this sequence to 11 different aromatic amines gave selective bromination in 36-91% yields, without formation of dibromides. This constitutes a good general method for the regioselective bromination of aromatic amines.
- Smith, Michael B.,Guo, Lisa,Okeyo, Sherrad,Stenzel, Jason,Yanella, James,LaChapelle, Eric
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p. 2321 - 2323
(2007/10/03)
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