- Synthesis of 4-methoxy-1H-phenalen-1-one: a subunit related to natural phenalenone-type compounds
-
4-Methoxy-1H-phenalen-1-one (4-methoxyperinaphthenone, 1), a subunit found in some Musa phytoalexins and related natural products from the Haemodoraceae, was synthesized starting from 2-methoxynaphthalene in five steps and an overall yield of 36%. A Heck-Fujiwara coupling between ethyl acrylate and 1-bromonaphthalene afforded the corresponding (E)-naphthylpropanoic acid which, after hydrogenolysis, was subjected to a one-pot Friedel-Crafts acylation-DDQ dehydrogenation procedure to furnish 1.
- Nanclares, Juliana,Gil, Jesús,Rojano, Benjamín,Saez, Jairo,Schneider, Bernd,Otálvaro, Felipe
-
-
Read Online
- Cetyltrimethylammonium bromide as an efficient catalyst for regioselective bromination of alkoxy naphthalenes with trimethyl benzyl ammonium tribromide: Synthetic and kinetic approach
-
Bromination of 2-alkoxynaphthalene (2-ANP) and its derivatives with trimethyl benzyl ammonium tribromide (TMBATB) did not proceed smoothly even under reflux conditions. But the addition of microconcentrations of cetyltrimethyl ammonium bromide (CTAB) to t
- Reddy, K. Rajendar,Rajanna,Uppalaiah,Ramgopal
-
-
Read Online
- Bis-selenonium Cations as Bidentate Chalcogen Bond Donors in Catalysis
-
Lewis acids are frequently employed in catalysis but they often suffer from high moisture sensitivity. In many reactions, catalysts are deactivated because of the problem that strong Lewis acids also bond to the products. In this research, hydrolytically stable bidentate Lewis acid catalysts derived from selenonium dicationic centers have been developed. The bis-selenonium catalysts are employed in the activation of imine and carbonyl groups in various transformations with good yields and selectivity. Lewis acidity of the bis-selenonium salts was found to be stronger than that of the monoselenonium systems, attributed to the synergistic effect of the two cationic selenonium centers. In addition, the bis-selenonium catalysts are not inhibited by strong bases or moisture.
- He, Xinxin,Wang, Xinyan,Tse, Ying-Lung Steve,Ke, Zhihai,Yeung, Ying-Yeung
-
p. 12632 - 12642
(2021/10/21)
-
- Bromination of phenyl ether and other aromatics with bromoisobutyrate and dimethyl sulfoxide
-
Bromoisobutyrate has been used for the first time as a general brominating source for the direct bromination of a diverse of simple phenyl ethers. Aromatic ethers bearing various substituents could be compatible in this reaction system delivering brominated arenes in moderate to good yields. The reaction system can also be expanded to bromination of phenols and unactivated arene. This process can be regarded as an alternative for the well-established bromination systems for bromoarene synthesis.
- Li, Jia-Qin,Chen, Xiao-Hui,Wang, Xian-Xun,Cui, Hai-Lei
-
supporting information
(2021/09/09)
-
- Catalytic Enantioselective Synthesis of Axially Chiral Diarylmethylidene Indanones
-
We describe the first atropselective Suzuki-Miyaura cross-coupling of β-keto enol triflates to access axially chiral (Z)-diarylmethylidene indanones (DAIs). The chemical, physical, and biological properties of DAIs are unknown, despite their being structurally similar to arylidene indanones, primarily due to the lack of racemic or chiral methods. Through this work, we demonstrate a general and efficient protocol for the racemic as well as the atropselective synthesis of (Z)-DAIs. An unusual intramolecular Morita-Baylis-Hillman reaction is utilized for the Z-selective synthesis of β-keto enol triflates.
- Kumar, Prashant,Shirke, Rajendra P.,Yadav, Sonu,Ramasastry
-
supporting information
p. 4909 - 4914
(2021/06/30)
-
- Axially Chiral 1,1'-Binaphthyl-2-Carboxylic Acid (BINA-Cox) as Ligands for Titanium-Catalyzed Asymmetric Hydroalkoxylation
-
Axially chiral, enantiopure 1,1'-binaphthyl-2-carboxylic acids (BINA-Cox) have recently been introduced as chiral ligands for transition metal catalysis. Together with equimolar, co-catalytic amounts of Ti(OiPr)4 and water they form an in situ catalyst that performs the asymmetric catalytic hydroalkoxylation of 2-allylphenols to 2-methylcoumarans at high temperature (240 °C, microwave heating). The synthesis of reference ligand 2'-MeO-BINA-Cox (L1) has been optimized and performed at molar scale. Synthetic routes have been developed to access a variety of substituted BINA-Cox ligands (>30 examples), which have been tested for ligand effects on the reference asymmetric cyclization of 2-allylphenol. The substrate range of asymmetric catalytic hydroalkoxylation has been explored through systematic substrate structure variations to define scope and limitations of the titanium-catalyzed process. The new substrates 2-(1-vinylcycloalkyl)phenols (1j, 1k), 2-(2-vinylphenyl)propan-2-ol (1t), and 2'-vinyl-[1,1'-biphenyl]-2-ol (1u) are shown to undergo asymmetric catalytic cyclization to benzodihydrofurans and benzo[c]chromene, respectively.
- Blazejak, Max,Helmbrecht, Sebastian L.,Hintermann, Lukas,Schlüter, Johannes
-
supporting information
(2020/04/15)
-
- Cooperativity within the catalyst: alkoxyamide as a catalyst for bromocyclization and bromination of (hetero)aromatics
-
Alkoxyamide has been reported as a catalyst for the activation ofN-bromosuccinimide to perform bromocyclization and bromination of a wide range of substrates in a lipophilic solvent, where adequate suppression of the background reactions was observed. The key feature of the active site is the alkoxy group attached to the sulfonamide moiety, which facilitates the acceptance as well as the delivery of bromonium species from the bromine source to the substrates.
- Mondal, Haripriyo,Sk, Md Raja,Maji, Modhu Sudan
-
supporting information
p. 11501 - 11504
(2020/10/12)
-
- Aryl halide and synthesis method and application thereof
-
The invention discloses a synthesis method of aryl halides (including aryl bromide shown as a formula (2) and aryl iodide shown as a formula (3)). All the systems are carried out in an air atmosphere,visible light is utilized to excite a substrate or a photosensitizer to catalyze the reaction; and in a reaction solvent, when aromatic hydrocarbon shown in the formula (1) and sodium bromide serve as raw materials, aryl bromide shown in the formula (2) is obtained through a reaction under the auxiliary action of an additive (protonic acid); or when aromatic hydrocarbon shown in the formula (1) and sodium iodide are used as raw materials, under the auxiliary action of an additive (protonic acid), aryl iodide shown in the formula (3) is obtained through reaction. The synthesis method has the advantages of cheap and accessible raw materials, simple reaction operation and mild reaction conditions. The method is compatible with the arylamine which is liable to be oxidized. The invention provides a new method for the synthesis of aryl halides, realizes the amplification of basic chemicals aryl halides including aryl bromide shown in the formula (2) and aryl iodide shown in the formula (3),and has wide application prospect and practical value.
- -
-
Paragraph 0100-0102
(2020/06/02)
-
- Visible-light-promoted oxidative halogenation of (hetero)arenes
-
Organic halides are critical building blocks that participate in various cross-coupling reactions. Furthermore, they widely exist as natural products and artificial molecules in drugs with important physiological activities. Although halogenation has been well studied, to the best of our knowledge, studies focussing on sensitive systems (e.g.aryl amines) have not been reported. Herein, we describe a compatible oxidative halogenation of (hetero)arenes with air as the oxidant and halide ions as halide sources under ambient conditions (visible light, air, aqueous system, room temperature, and normal pressure). Moreover, this protocol is practically feasible for gram-scale synthesis, showing potential for industrial application.
- Jiang, Xuefeng,Li, Yiming,Lu, Lingling
-
supporting information
p. 5989 - 5994
(2020/10/18)
-
- Electrocatalytic Deuteration of Halides with D2O as the Deuterium Source over a Copper Nanowire Arrays Cathode
-
Precise deuterium incorporation with controllable deuterated sites is extremely desirable. Here, a facile and efficient electrocatalytic deuterodehalogenation of halides using D2O as the deuteration reagent and copper nanowire arrays (Cu NWAs) electrochemically formed in situ as the cathode was demonstrated. A cross-coupling of carbon and deuterium free radicals might be involved for this ipso-selective deuteration. This method exhibited excellent chemoselectivity and high compatibility with the easily reducible functional groups (C=C, C≡C, C=O, C=N, C≡N). The C?H to C?D transformations were achieved with high yields and deuterium ratios through a one-pot halogenation–deuterodehalogenation process. Efficient deuteration of less-active bromide substrates, specific deuterium incorporation into top-selling pharmaceuticals, and oxidant-free paired anodic synthesis of high-value chemicals with low energy input highlighted the potential practicality.
- Chong, Xiaodan,Han, Shuyan,Li, Mengyang,Liu, Cuibo,Zhang, Bin
-
supporting information
p. 18527 - 18531
(2020/08/21)
-
- 2 - Hydroxynaphthalene -1 - boric acid synthesis method (by machine translation)
-
The invention discloses a 2 - hydroxynaphthalene - 1 - boric acid synthesis method, comprises the following steps: 1), 1 - bromo - 2 - naphthol synthetic; 2), hydroxy alkylated protection: [...], containing 1 - bromo - 2 - naphthol of the mixed solution, the heat of the reaction of dimethyl sulfate, shall be 1 - bromo - 2 - methoxy; 3), [...] boric acid-hydrogen substituted: 1 - bromo - 2 - methoxy, boric acid ester, such as n-butyllithium in the heat of the reaction, shall be 2 - armor chromene - 1 - boric acid; 4), demethylation reaction: 2 - armor chromene - 1 - boronic acid, boron tribromide after treatment after the reaction, a 2 - hydroxy - naphthalene - 1 - boric acid. The method of the invention can be a single high-purity, high yield of the target product, effectively solves the 2 - hydroxy - naphthalene - 1 - boric acid preparation process instability problems. (by machine translation)
- -
-
Paragraph 0058; 0063; 0064; 0065
(2019/02/19)
-
- Atom-economical brominations with tribromide complexes in the presence of oxidants
-
Bromination is an important transformation in organic synthesis, and novel efficient bromination techniques are still required. Herein, we demonstrate atom-economical brominations using (DMI)2HBr3, a novel tribromide complex, with oxidants such as DMSO and Oxone. Using this system, olefinic and aromatic brominations, as well as selective α-monobrominations of ketones proceeded well to afford the desired bromides in good yields. Importantly, in these reactions all of the bromine atoms in this complex are used to brominate.
- Yubata, Kotaro,Matsubara, Hiroshi
-
supporting information
p. 1001 - 1004
(2019/03/13)
-
- Organic semiconductor photocatalyst can bifunctionalize arenes and heteroarenes
-
Photoexcited electron-hole pairs on a semiconductor surface can engage in redox reactions with two different substrates. Similar to conventional electrosynthesis, the primary redox intermediates afford only separate oxidized and reduced products or, more rarely, combine to one addition product. Here, we report that a stable organic semiconductor material, mesoporous graphitic carbon nitride (mpg-CN), can act as a visible-light photoredox catalyst to orchestrate oxidative and reductive interfacial electron transfers to two different substrates in a two- or three-component system for direct twofold carbon–hydrogen functionalization of arenes and heteroarenes. The mpg-CN catalyst tolerates reactive radicals and strong nucleophiles, is straightforwardly recoverable by simple centrifugation of reaction mixtures, and is reusable for at least four catalytic transformations with conserved activity.
- Ghosh, Indrajit,Khamrai, Jagadish,Savateev, Aleksandr,Shlapakov, Nikita,Antonietti, Markus,K?nig, Burkhard
-
p. 360 - 366
(2019/08/15)
-
- Environmentally benign indole-catalyzed position-selective halogenation of thioarenes and other aromatics
-
Halogenated aromatic compounds are the cores of many pharmaceutical, agricultural and chemical products but they are commonly prepared using electrophilic halogenation reactions in non-green chlorinated solvents under harsh conditions. A separate problem happens in the aromatic halogenation of thioarenes because they readily undergo oxidative side-reactions. Herein we report an environmentally benign electrophilic bromination of aromatics using an indole-catalytic protocol, which is suitable for a wide range of substrates including thioarenes.
- Shi, Yao,Ke, Zhihai,Yeung, Ying-Yeung
-
supporting information
p. 4448 - 4452
(2018/10/17)
-
- Applications of Selenonium Cations as Lewis Acids in Organocatalytic Reactions
-
The use of trisubstituted selenonium salts as organic Lewis acids in electrophilic halogenation and aldol-type reactions has been developed. The substrate scope is broad. The reaction conditions are mild and compatible with various functionalities. This study opens a new avenue for the development of nonmetallic Lewis acid catalysis.
- He, Xinxin,Wang, Xinyan,Tse, Ying-Lung (Steve),Ke, Zhihai,Yeung, Ying-Yeung
-
supporting information
p. 12869 - 12873
(2018/09/14)
-
- Regioselective Halogenation of Arenes and Heterocycles in Hexafluoroisopropanol
-
Regioselective halogenation of arenes and heterocycles with N-halosuccinimides in fluorinated alcohols is disclosed. Under mild condition reactions, a wide diversity of halogenated arenes are obtained in good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of one-pot sequential halogenation and halogenation-Suzuki cross-coupling reactions.
- Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
-
p. 930 - 938
(2018/01/28)
-
- Practical, mild and efficient electrophilic bromination of phenols by a new I(iii)-based reagent: The PIDA-AlBr3 system
-
A practical electrophilic bromination procedure for phenols and phenol-ethers was developed under efficient and very mild reaction conditions. A broad scope of arenes was investigated, including the benzimidazole and carbazole core as well as analgesics such as naproxen and paracetamol. The new I(iii)-based brominating reagent PhIOAcBr is operationally easy to prepare by mixing PIDA and AlBr3. Our DFT calculations suggest that this is likely the brominating active species, which is prepared in situ or isolated after centrifugation. Its stability at 4 °C after preparation was confirmed over a period of one month and no significant loss of its reactivity was observed. Additionally, the gram-scale bromination of 2-naphthol proceeds with excellent yields. Even for sterically hindered substrates, a moderately good reactivity is observed.
- Satkar, Yuvraj,Ramadoss, Velayudham,Nahide, Pradip D.,García-Medina, Ernesto,Juárez-Ornelas, Kevin A.,Alonso-Castro, Angel J.,Chávez-Rivera, Ruben,Jiménez-Halla, J. Oscar C.,Solorio-Alvarado, César R.
-
p. 17806 - 17812
(2018/05/28)
-
- Photocatalytic Oxidative Bromination of Electron-Rich Arenes and Heteroarenes by Anthraquinone
-
The estimated excited oxidation potential of sodium anthraquinone-2-sulfonate (SAS) increases from 1.8 V to about 2.3 V vs SCE by protonation with Br?nsted acids. This increased photooxidation power of protonated anthraquinone was used for the regio-selective oxidative bromination of electron rich (hetero)arenes and drugs in good yield. The mild reaction conditions are compatible with many functional groups, such as double and triple bonds, ketones, amides and amines, hydroxyl groups, carboxylic acids and carbamates. Mechanistic investigations indicate the photooxidation of the arene followed by nucleophilic bromide addition as the likely pathway. (Figure presented.).
- Petzold, Daniel,K?nig, Burkhard
-
supporting information
p. 626 - 630
(2017/11/22)
-
- Zwitterionic-Salt-Catalyzed Site-Selective Monobromination of Arenes
-
A zwitterionic-salt-catalyzed electrophilic monobromination of arenes with high regioselectivity has been developed. Under mild reaction conditions, a wide range of monobrominated aromatic compounds can be obtained in excellent yields. The reaction can be operated using an extremely low catalyst loading (0.05 mol %) with the inexpensive brominating agent N-bromosuccinimide. The versatility of this catalytic protocol has been demonstrated by the scale-up reaction with a 0.01 mol % catalyst loading to provide the selectively halogenated compound in quantitative yield.
- Xiong, Xiaodong,Tan, Fei,Yeung, Ying-Yeung
-
supporting information
p. 4243 - 4246
(2017/08/23)
-
- ORGANIC COMPOUND AND ORGANIC OPTOELECTRIC DEVICE AND DISPLAY DEVICE
-
The present invention relates to an organic compound represented by chemical formula 1, an organic optoelectronic device including the organic compound, and a display device. In chemical formula 1, X is O, S, CRaRb or SiRcRd; and Y is N or CRe, wherein at least one Y is N; Ar1 is a substituted or unsubstituted fused ring; Ra to Rd are independently hydrogen, deuterium, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C12 cycloalkyl group, a substituted or unsubstituted C6 to C12 aryl group, a substituted or unsubstituted C3 to C12 heterocyclic group, or a combination thereof; and Re is hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, or a combination thereof.COPYRIGHT KIPO 2016
- -
-
Paragraph 0238; 0241; 0245; 0246
(2017/01/02)
-
- Photocatalytic Selective Bromination of Electron-Rich Aromatic Compounds Using Microporous Organic Polymers with Visible Light
-
Pure organic, heterogeneous, metal-free, and visible light-active photocatalysts offer a more sustainable and environmentally friendly alternative to traditional metal-based catalysts. Here we report a series of microporous organic polymers containing photoactive conjugated organic semiconductor units as heterogeneous photocatalysts for a visible-light-promoted, highly selective bromination reaction of electron-rich aromatic compounds using HBr as a bromine source and molecular oxygen as a clean oxidant. Via a simple Friedel-Crafts alkylation reaction, the microporous organic polymers were obtained by cross-linking of organic semiconductor compounds with defined valence and conduction band positions. The utilization of the simply prepared porous polymer-based photocatalytic systems opens new opportunities toward a sustainable and efficient material design for catalysis.
- Li, Run,Wang, Zi Jun,Wang, Lei,Ma, Beatriz Chiyin,Ghasimi, Saman,Lu, Hao,Landfester, Katharina,Zhang, Kai. A. I.
-
p. 1113 - 1121
(2016/02/18)
-
- A Doubly Biomimetic Synthetic Transformation: Catalytic Decarbonylation and Halogenation at Room Temperature by Vanadium Pentoxide
-
The halogenation of the C?H bond by metal-oxo-peroxo species and the decarbonylation of aldehydes by metal-peroxo species are performed routinely in biological systems. However, metal-mediated decarbonylative halogenation is unknown in nature. In this work, we have shown that widely available V2O5 and VO(acac)2 (acac=acetylacetonate) can catalyze decarbonylative halogenation through the generation of an intermediate vanadium-oxo-peroxo species, which was characterized by using 51 V NMR, UV/Vis, and resonance Raman spectroscopy. Further detection of formic acid from the reaction mixture confirmed the biomimetic aspects of decarbonylative halogenation. A detailed experimental and DFT study indicated a concerted mechanism for this decarbonylative halogenation performed under simple and mild reaction conditions.
- Rana, Sujoy,Pandey, Bhawana,Dey, Aniruddha,Haque, Rameezul,Rajaraman, Gopalan,Maiti, Debabrata
-
p. 3367 - 3374
(2016/11/16)
-
- The transition metal compound and a transition metal catalyst composition
-
Provided are transition metal catalytic systems for preparing ethylene homopolymers or copolymers of ethylene with α-olefins. More specifically, provided are Group 4 transition metal catalysts, which is characterized in that the Group 4 transition metal catalyst comprises around the Group 4 transition metal a cyclopentadiene derivative, and at least one naphthoxide ligand(s) having aryl substituent(s) that function(s) as an electron donor and serve(s) to stabilize the catalyst system by surrounding an oxygen atom that links the ligand to the transition metal at 2-position, and there is no cross-linkage between the ligands; catalytic systems comprising such transition metal catalyst and aluminoxane cocatalyst or boron compound cocatalyst; and processes for preparing ethylene homopolymers or copolymers of ethylene with α-olefins by using the same.
- -
-
Paragraph 0092; 0093
(2016/12/22)
-
- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
-
We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
-
supporting information
p. 2154 - 2156
(2015/03/18)
-
- Visible-light photoredox catalysis enabled bromination of phenols and alkenes
-
A mild and efficient methodology for the bromination of phenols and alkenes has been developed utilizing visible light-induced photoredox catalysis. The bromine was generated in situ from the oxidation of Br- by Ru(bpy)33+, both of which resulted from the oxidative quenching process.
- Zhao, Yating,Li, Zhe,Yang, Chao,Lin, Run,Xia, Wujiong
-
p. 622 - 627
(2014/04/17)
-
- Catalytic electrophilic halogenations and haloalkoxylations by non-heme iron halides
-
Synthetic non-heme iron halides promote sub-stoichiometric aliphatic halogenation reactions via a radical mechanism. Complementary to such activity, we have developed an electrophilic halogenation of arenes employing non-heme iron halides. A catalytic version of these reactions has also been developed using potassium halide as the source of halogen atom for arenes at room temperature. Efforts towards understanding the mechanism of these catalytic halogenation reactions led to the discovery of the haloalkoxylation of olefins by a non-heme iron complex. Implications of these findings with respect to natural transformations are also discussed.
- Rana, Sujoy,Bag, Sukdev,Patra, Tuhin,Maiti, Debabrata
-
supporting information
p. 2453 - 2458
(2014/09/30)
-
- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
-
We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
-
supporting information
p. 2154 - 2156
(2014/04/03)
-
- Kinetic and computational studies on Pd(I) dimer-mediated halogen exchange of aryl iodides
-
Building on our previous discovery and reactivity explorations of the Pd(I) dimer [(PtBu3)PdBr]2-mediated halogen exchange of aryl iodides [ Chem. Sci. 2013, 4, 4434 ], this report presents kinetic studies of this process, giving first-order kinetic dependence in the Pd(I) dimer and aryl iodide. An activation free energy barrier of ΔG? = 24.9 ± 3.3 kcal/mol was experimentally determined. Extensive computational studies on the likely reaction pathway were subsequently carried out. A variety of DFT methods were assessed, ranging from dispersion-free methods to those that better account for dispersion (M06L, ωB97XD, D3-DFT). While significant discrepancies in the quantitative prediction of activation barriers were observed, all computational methods consistently predicted the analogous qualitative reactivity that is in agreement with all spectroscopic and reactivity data collected. Overall, these data provide compelling additional support of the direct reactivity of Pd(I)-Pd(I) with aryl iodides.
- Kalvet, Indrek,Bonney, Karl J.,Schoenebeck, Franziska
-
supporting information
p. 12041 - 12046
(2015/02/19)
-
- Fast and efficient bromination of aromatic compounds with ammonium bromide and Oxone
-
A highly efficient, rapid and regioselective protocol was developed for the ring bromination of aromatic compounds under mild conditions with ammonium bromide as a source of bromine source and Oxone (potassium peroxysulfate) as an oxidant. No metal catalyst or acidic additive is required. A variety of aromatic compounds, including methoxy, hydroxy, amino, and alkyl arenes, reacted smoothly to give the corresponding monobrominated products in good to excellent yields in very short reaction times. Moreover, dibromination of deactivated anilines to give the corresponding dibromides proceeded in high yields. Interestingly, 1-(2-naphthyl)ethanone provided a ring-brominated product. Georg Thieme Verlag Stuttgart . New York.
- Naresh, Mameda,Arun Kumar, Macharla,Mahender Reddy, Marri,Swamy, Peraka,Nanubolu, Jagadeesh Babu,Narender, Nama
-
p. 1497 - 1504
(2013/06/27)
-
- Dinuclear Pd(i) complexes - Solely precatalysts? Demonstration of direct reactivity of a Pd(i) dimer with an aryl iodide
-
This report provides experimental, computational and spectroscopic data in support of the direct reactivity of a Pd(i) dimer with an aryl iodide, resulting in Br/I halogen exchange between the complex and the aryl iodide. The reactivity could not be achieved through analogous Pd(0) conditions, demonstrating the distinct reactivities at such multiple Pd-sites. Computational studies support that the direct oxidative addition to ArI by the dinuclear metal complex is energetically feasible.
- Bonney, Karl J.,Proutiere, Fabien,Schoenebeck, Franziska
-
p. 4434 - 4439
(2013/11/19)
-
- In situ acidic carbon dioxide/water system for selective oxybromination of electron-rich aromatics catalyzed by copper bromide
-
Carbon dioxide, being one of the major greenhouse gases responsible for global warming, its atmospheric level grows ever faster since the beginning of industrial era. Great efforts have been devoted to developing versatile technologies/processes to adjust and manipulate the rapid growth of CO 2 emission. Besides CO2 capture and storage/sequestration (CCS) to control its emission, chemical utilization of the captured CO 2 (CCU) emerges to be a rational technique for economical benefits as well as environmental concerns. As for the aim of CO2 utilization, an environmentally benign CO2/water reversible acidic system was developed for the copper (II)-catalyzed selective oxybromination of electron-rich aromatics without the need of any conventional acid additive and organic solvent. Notably, up to 95% yields of the bromination products were attained with good regio-selectivity when cupric bromide was used as the catalyst and lithium bromide as a cheap and easy handling bromine source under supercritical CO2. The catalytic system worked well for electron-rich aromatics including ethers, sulfides and mesitylene. Carbonic acid in situ formed from CO2 and water is supposed to act as the proton donator in the Bronsted acid-promoted reaction. Notably, CO2 in this study serves as a reaction medium and a promoter in conjunction with water and also provides safe environment for aerobic reactions. Given with excellent reaction efficiency as well as no need of neutralization disposal, this process thus represents an environmentally friendly approach for aerobic bromination of aromatics with essential reduction of CO2 emission as well as an economically beneficial way for application of captured CO2.
- Liu, An-Hua,Ma, Ran,Zhang, Meng,He, Liang-Nian
-
-
- In situ acidic carbon dioxide/ethanol system for selective oxybromination of aromatic ethers catalyzed by copper chloride
-
An environmentally benign carbon dioxide/ethanol reversible acidic system was developed for the copper(II)-catalyzed regioselective oxybromination of aromatic ethers without the need of any conventional acid additive and organic solvent. Good to excellent yields together with very good regioselectivity were achieved when easily available cupric chloride dihydrate was used as catalyst and lithium bromide as the cheap and easy-to-handle bromine source under supercritical carbon dioxide conditions. Notably, the catalytic system worked well for a wide range of aromatic ethers including sulfides, resulting in the formation of the mono-brominated products in high yields and exclusive regioselectivity. The alkylcarbonic acid in situ formed from ethanol and carbon dioxide is assumed to play the crucial role in the Braonsted acid-promoted reaction, which could probably act as the proton donator, and was studied employing in situ FT-IR technique under carbon dioxide pressure by monitoring the vibration shift of the hydroxy group of ethanol. Given with excellent bromine atom efficiency as well as no need of neutralization in waste disposal, this approach thus represents a greener pathway for the aerobic bromination of aromatic ethers. A possible catalytic cycle for the in situ alkylcarbonic acid-assisted oxybomination and the effect of supercritical carbon dioxide, i.e., activation of alcohol and enhancement of mass transfer are also discussed. Copyright
- Liu, An-Hua,He, Liang-Nian,Hua, Fang,Yang, Zhen-Zhen,Huang, Cheng-Bin,Yu, Bing,Li, Bin
-
experimental part
p. 3187 - 3195
(2012/01/06)
-
- Simple and improved regioselective brominations of aromatic compounds using N-benzyl-N,N-dimethylanilinium peroxodisulfate in the presence of potassium bromide under mild reactions conditions
-
A simple, efficient, and mild method for the selective bromination of some activated aromatic compounds using N-benzyl-N,N-dimethylanilinium peroxodisulfate in the presence of potassium bromide in non-aqueous solution is reported. The results obtained revealed good to excellent selectivity between the ortho and para positions of phenols and methoxyarenes.
- Ghasemnejad-Bosra, Hassan,Ramzanian-Lehmali, Farhad,Jafari, Somaye
-
experimental part
p. 685 - 692
(2012/01/16)
-
- Oxidative bromination reaction using Cu2+- perfluorophthalocyanine-immobilized silica gel catalyst under mild reaction conditions
-
A simplified, facile route has been applied for the grafting of copper(II) perfluorophthalocyanine complex onto functionalized silica gel. The resulting organic-inorganic hybrid material is used as an efficient and recyclable catalyst for the regioselective oxidative bromination of various aromatic substrates using KBr/H2O2 as the reagents, affording high yields under mild conditions. High catalytic activity efficiency could be attributed to the heterogenization of soluble metal complexes on the high surface area host.
- Sharma,Sharma, Chetna
-
experimental part
p. 4415 - 4418
(2010/09/20)
-
- Oxidative bromination of aromatic compounds using O-iodoxybenzoic acid with tetraethylammonium bromide
-
A mild and selective procedure for the bromination of activated arenes using o-iodoxybenzoic acid and tetraethylammonium bromide is presented. The reactions were carried out at room temperature and gave moderate to excellent yields. Copyright Taylor & Francis Group, LLC.
- Bhalerao, Dinesh S.,Mahajan, Ulhas S.,Akamanchi, Krishnacharya G.
-
experimental part
p. 2814 - 2819
(2009/04/04)
-
- Regioselective, photochemical bromination of aromatic compounds using N-bromosuccinimide
-
Regioselective nuclear bromination of aromatic compounds is investigated with N-bromosuccinimide as the brominating agent under UV irradiation to afford the corresponding brominated compounds. The reaction proceeds at ambient temperature (30 ± 2 °C) without any catalyst. In most of the reactions, regioselectively mono-brominated products are obtained in good to high yields. The conversion and selectivity for bromination depend on the nature of the substituent on the aromatic ring.
- Chhattise, Prakash K.,Ramaswamy,Waghmode, Suresh B.
-
p. 189 - 194
(2008/03/30)
-
- 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
-
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
-
p. 1282 - 1284
(2008/03/27)
-
- Bromination of some aromatic compounds with potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate
-
A simple, efficient, and mild method for selective bromination of some activated aromatic compounds using potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate in nonaqueous solution is reported. The results obtained revealed good to excellent selectivity between ortho and para positions of phenols and methoxyarenes. Copyright Taylor & Francis Group, LLC.
- Tajik, Hassan,Mohammadpoor-Baltork, Iraj,Albadi, Jalal
-
p. 323 - 328
(2007/10/03)
-
- Efficient electrophilic cobromination of alkenes and bromination of activated arenes with bromodichloroisocyanuric acid under mild conditions
-
Efficient methodologies for the preparation of bromodichloroisocyanuric acid were developed (70-75%). This new reagent is very efficient for regioselective electrophilic bromination of activated arenes (86-93%) and cobromination of alkenes with oxygenated nucleophiles (31-98%). The reaction of bromodichloroisocyanuric acid with anisole, acetanilide, N-methylacetanilide leads to 4-substituted monobromoarene and with 2-methoxynaphthalene leads to 1-bromo-2-methoxynaphthalene. Alkenes were cobrominated in the presence of oxygenated nucleophilic solvents (water, alcohols, and acetic acid), leading to the corresponding bromohydrins, β-bromoethers and β-bromoacetates. Georg Thieme Verlag Stuttgart.
- De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C. S.
-
p. 1687 - 1690
(2007/12/28)
-
- A convenient and regioselective oxidative bromination of electron-rich aromatic rings using potassium bromide and benzyltriphenylphosphonium peroxymonosulfate under nearly neutral reaction conditions
-
Regioselective oxidative bromination of electron-rich aromatic rings has been studied using potassium bromide as a bromine source in the presence of benzyltriphenylphosphonium peroxymonosulfate as oxidant under nearly neutral reaction conditions. In most cases we obtained monobrominated derivatives regioselectively and in good to high yields without the aid of strong acids.
- Adibi, Hadi,Hajipour, Abdol R.,Hashemi, Majid
-
p. 1255 - 1259
(2007/10/03)
-
- Copper(II) bromide: A simple and selective monobromination reagent for electron-rich aromatic compounds
-
Copper(II) bromide was found to be a simple and efficient reagent for monobromination of electron-rich aromatic compounds at room temperature. The reaction proceeded smoothly with phenols, aryl alkyl ethers, and aromatic amines to afford the corresponding monobrominated product selectively in moderate to good yields. Copyright Taylor & Francis Group, LLC.
- Bhatt, Suchitra,Nayak, Sandip K.
-
p. 1381 - 1388
(2008/02/01)
-
- LEWIS ACID CATALYZED HALOGENATION OF ACTIVATED CARBON ATOMS
-
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.
- -
-
Page/Page column 23-24
(2008/06/13)
-
- Sodium nitrite-catalyzed oxybromination of aromatic compounds and aryl ketones with a combination of hydrobromic acid and molecular oxygen under mild conditions
-
A novel and efficient catalytic system for the oxybromination of aromatic compounds and aryl ketones utilizing a combination of aqueous hydrobromic acid and molecular oxygen in the presence of sodium nitrite under mild conditions has been developed. The newly developed catalytic system utilizes cheap and readily available reactants, exhibits high bromine atom economy and releases only innocuous water as the by-product.
- Zhang, Guofu,Liu, Renhua,Xu, Qing,Ma, Lixin,Liang, Xinmiao
-
p. 862 - 866
(2007/10/03)
-
- A new regioselective bromination of activated aromatic rings
-
An efficient and highly regioselective bromination of activated aromatic rings promoted by tribromoisocyanuric acid by in situ generation of Br + has been developed. A range of aromatic compounds were reacted with tribromoisocyanuric acid and trichloroisocyanuric acid and sodium bromide. Georg Thieme Verlag Stuttgart.
- De Almeida, Leonardo S.,Esteves, Pierre M.,De Mattos, Marcio C. S.
-
p. 221 - 223
(2007/10/03)
-
- A new ring bromination method for aromatic compounds under solvent-free conditions with NBS/Al2O3
-
Alumina supported N-bromosuccinimide was found to be an efficient reagent for ring bromination of a number of aromatic compounds under solvent-free conditions. In the absence of the alumina the reactions are slow and some of the substrates are recovered unchanged. Under the reaction conditions aromatic oximes are converted into the corresponding carbonyl compounds. The method is simple, safe and rapid.
- Imanzadeh, Gholamhassan K.,Zamanloo, Mohammad R.,Eskandari, Habibollah,Shayesteh, Keyvan
-
p. 151 - 153
(2007/10/03)
-
- Grindstone chemistry: (Diacetoxyiodo)benzene-mediated oxidative nuclear halogenation of arenes using NaCl, NaBr or I2
-
A technique of "Grindstone chemistry" is applied to the solvent-free halogenation of arenes with NaCl, NaBr or I2 using (diacetoxyiodo)benzene as the oxidant. Improved yields and higher purities of the products are observed compared with those from established methods.
- Karade,Tiwari,Huple,Siddiqui
-
p. 366 - 368
(2007/10/03)
-
- SULFONYL SUBSTITUTED N-(BIARYLMETHYL) AMINOCYCLOPROPANECARBOXAMIDES
-
N-(Sulfonyloxybiarylmethyl) aminocyclopropanecarboxamide derivatives are bradykinin B1 antagonists or inverse agonists useful in the treatment or prevention of symptoms such as pain and inflammation associated with the bradykinin B1 pathway.
- -
-
Page/Page column 39
(2008/06/13)
-
- Solid state S-methylation of thiols and O-methylation of phenols and naphthols with dimethyl sulfate under microwave irradiation
-
Mild and efficient S-methylation of thiols and o-methylation of phenols and naphthals occurs with dimethyl sulfate (DMS) supported on basic alumina under microwave irradiation in solventless system. Copyright Taylor & Francis Inc.
- Heravi, Majid M.,Ahari, Neda Zamani,Oskooie, Hossein A.,Ghassemzadeh, Mitra
-
p. 1701 - 1712
(2007/10/03)
-
- Bromination of aromatic compounds with potassium bromide in the presence of poly(4-vinylpyridine)-supported bromate in nonaqueous solution
-
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
-
p. 1947 - 1952
(2007/10/03)
-
- Lewis acid catalyzed highly selective halogenation of aromatic compounds
-
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
-
p. 2837 - 2842
(2007/10/03)
-