- Facile and sensitive spectrophotometric determination of propoxur in formulations and environmental samples
-
A facile, rapid, and sensitive spectrophotometric method for the determination of propoxur in insecticidal formulations, fortified water, vegetables, agricultural wastewater, and agricultural soil samples has been elaborated. The proposed method is based on the hydrolysis of propoxur under basic conditions, followed by instantaneous azo coupling of the resulting 2-isopropoxyphenol with the anilines 2a - c. This yielded the orange-red chromophore 3a (λmax = at 470 nm). the pale-red coupling product 3b (490 nm), or the red derivative 3c (478 nm), which are stable for 46 h, 38 h, and 24 h, respectively, and could be readily analyzed spectrophotometrically.
- Kumar, Kailasa Suresh,Suvardhan, Kanchi,Rekha, Dasari,Jayaraj,Chiranjeevi, Pattium
-
-
Read Online
- Oxidative bromination of aniline and its derivatives
-
Oxidative bromination of aniline and its derivatives containing various substituents (CH3, Cl, NO2, COOH) in ortho, meta, and para positions with a brominating mixture of NaBr (KBr) and 20-22% hydrogen peroxide in 6-8% hydrochloric acid at the molar ratio aniline: NaBr (KBr): H 2O2: HCl = 1: 3.5: 3.2: 4.5 is described.
- Salakhov,Bagmanov,Umaeva,Bagmanova
-
-
Read Online
- An alternative synthesis of 2,6-dimethoxyl-1,4-benzoquinone
-
An economic four-step synthesis of 2,6-dimethoxy-1,4-benzoquinone was achieved in 68 % overall yield starting from aniline. The reaction sequence involved conversion to1,3,5-tribromoaniline, deamination, methoxylation, and oxidation. The procedure is operationally simple and amenable to scale-up production.
- Wang, Qian,Yang, Jian,Zheng, Yang,Liao, Xiali
-
-
Read Online
- Synthesis method of high-purity phloroglucinol compound
-
The invention discloses a one-step chemical catalytic synthesis method of high-purity phloroglucinol by taking 3,5-dichlorophenol as a starting material and taking strong base and a catalyst as auxiliary materials. Through the method, the phloroglucinol compound with high molar yield, high purity and low cost can be effectively synthesized.
- -
-
Paragraph 0018
(2021/06/09)
-
- A Practical Procedure for Regioselective Bromination of Anilines
-
A highly practical procedure for the preparation of bromoanilines by using copper-catalyzed oxidative bromination has been developed. Treatment of free anilines with readily available NaBr and Na 2S 2O 8in the presence of a catalytic amount of CuSO 4·5H 2O enabled regioselective bromination.
- Takahashi, Yusuke,Seki, Masahiko
-
p. 1828 - 1832
(2021/04/15)
-
- Crystal structure, NMR and catalytic properties of a bis-peroxovanadium [NH4][VO(O2)2(mpa)]·H2O
-
By reacting NH4VO3 and mpa (mpa = 4-methoxypicolinamide) in the presence of H2O2, a bis-peroxovanadium [NH4][VO(O2)2(mpa)]·H2O (1) was obtained and characterized by X-ray single-crystal diffraction. Structural analyses demonstrate that 1 belongs to the monoclinic space group P21/c and consists of a bis-peroxovanadium [VO(O2)2(mpa)]?, one NH4+ counterion and one free lattice water. Adjacent [VO(O2)2(mpa)]? anions construct a 3D supramolecular framework through intra- and intermolecular hydrogen bonding interactions. The compositions of 1 in solution are investigated by using multinuclear (1H, 13C, and 51V) magnetic resonance, COSY, HSQC, HMBC, and variable temperature NMR in a 0.15 mol L?1 NaCl/D2O solution that mimics the physiological conditions. Comparing the results of single-crystal X-ray and NMR experiments, the VV ion in the undissociated [VO(O2)2(mpa)]? in solution displays a similar seven-coordinate distorted pentagonal bipyramidal geometry with the solid-state crystal. The catalytic activity of the 1 in the oxidative bromination for phenol/aniline-like compounds to mimic bromoperoxidases reactivity was also studied.
- Chen, Ping,Zhang, Shaowei,Zhang, Jie,Xia, Wen,Yu, Xianyong
-
p. 239 - 250
(2019/02/01)
-
- Sodium sulfate-hydrogen peroxide-sodium chloride adduct: selective protocol for the oxidative bromination, iodination and temperature dependent oxidation of sulfides to sulfoxides and sulfones
-
The regioselective bromination and iodination of unprotected aromatic primary amines using enclathrated hydrogen peroxide as an oxidant under mild conditions has been developed, in which potassium bromide (KBr) and potassium iodide (KI) were used as brominating and iodinating agents, respectively. The adduct shows not only regioselectivity for para- or ortho-isomers but also a remarkable chemoselectivity for monobromination. Selective oxidation of sulfides to sulfoxides and sulfones has also been studied and good to excellent yields of the desired products were obtained. Acetic acid was found to be the solvent of choice for these reactions. This simple method represents an ecologically benign and alternative pathway for the oxidative halogenation of anilines and the oxidation of sulfides to sulfoxides and sulfones.
- Gayakwad, Eknath M.,Patel, Khushbu P.,Shankarling, Ganapati S.
-
supporting information
p. 6001 - 6009
(2019/04/17)
-
- Method of catalytically synthesizing polybromo-aniline in water phase
-
The invention discloses a method of catalytically synthesizing polybromo-aniline in a water phase. The method comprises following steps: adding a catalytic amount of a free radical initiator, aniline derivatives, cheap and low-toxic bromine salts, and water into a reactor; carrying out reactions in a photocatalytic reaction instrument under power of 5W at a room temperature; after a while, extracting the reaction product by ethyl acetate, and carrying out recrystallization to obtain polybromo-aniline; wherein the free radical initiator is eosin, sodium persulfate, or potassium persulfate. The power of the incandescent lamp of the photocatalytic reaction instrument is 5W. The free radical initiator and bromine salts are cheap and easily available. The method is an ideal synthesis method of polybromo-aniline. Cheap and low-toxic bromine salts are used to replace liquid bromine. The cheap and easily available free radical initiator is used to replace unstable and explosive hydrogen peroxide. After 4 to 10 hours of reactions under the power of 5W, polybromo-aniline can be synthesized, the yield and the reaction selectivity are high, the byproducts are few, and the post treatment is simple.
- -
-
Paragraph 0012-0017
(2019/10/04)
-
- Crystal structure and catalytic properties of a vanadium complex cis-[VO2(Him-py)(im-py)]2·3H2O
-
The coordination behavior of Him-py (2-(1H-imidazol-2-yl)pyridine) toward vanadium has been explored. The six-coordinate complex, cis-[VO2(Him-py)(im-py)]2·3H2O (1), was synthesized by the coordination reaction of NH4VO3 and Him-py in the aqueous methanol solution, which was characterized by single-crystal X-ray technology. It belongs to the monoclinic space group P21/n with a = 8.0756(6), b = 19.3531(15), c = 11.4433(8), β = 106.905(2), V = 1711.2(2), and Z = 2. The crystal structure shows that the six-coordinate vanadium is bonded to two cis-oxido ligands and two bidentate ligands, Him-py and im-py. Interestingly, when crystals of 1 were immersed in H2O2, a peroxovanadium compound, (H2im-py)[OV(O2)2(Him-py)] (2), was obtained, which crystallizes in the orthorhombic space group Fdd2 with a = 22.600(2), b = 22.7259(13), c = 18.0146(11), V = 9252.4(12), and Z = 16, and consists of a seven-coordinate peroxovanadate(V) ion, one Him-py and one H2im-py ligand. Moreover, we also studied the catalytic activity of 1 in the oxidative bromination of phenol/aniline-like compounds towards mimicking bromoperoxidase reactivity.
- Sun, Meng,Zhang, Shaowei,Zhang, Jie,Xia, Wen,Chen, Jialiang,Yu, Xianyong
-
p. 1899 - 1909
(2019/06/04)
-
- Unusual Chemistry in an Uncatalyzed Bromate-Aniline Oscillator: Ring-Contraction Oxidation of Aniline with Pulsative CO2 Production
-
The bromate-aniline oscillatory reaction was discovered 4 decades ago, but neither the detailed mechanism nor the key products or intermediates of the reaction were described. We report herein a detailed study of this reaction, which yielded new insights. We found that oscillatory oxidation of aniline by acidic bromate proceeds, to a significant extent, via a novel reaction pathway with the periodic release of carbon dioxide. Several products were isolated, and their structures, not described so far, were justified on the basis of MS and NMR. One of the main products of the reaction associated with the CO2 release route can be assigned to 2,2-dibromo-5-(phenylimino)cyclopent-3-en-1-one. A number of known compounds produced in the studied reaction, including unexpected brominated 1-phenylpyrroles and 1-phenylmaleimides, were identified by comparison with standards. A mechanism is suggested to explain the appearance of the detected compounds, based on coupling of the anilino radical with the produced 1,4-benzoquinone. We assume that the radical adduct reacts with bromine to form a cyclopropanone intermediate that undergoes a Favorskii-type rearrangement. Further oxidation and bromination steps including decarboxylation lead to the found brominated phenyliminocyclopentenones. The detected derivatives of 1-phenylpyrrole could be produced by a one-electron oxidation of a proposed intermediate 2-phenylamino-5-bromocyclopenta-1,3-dien-1-ol followed by β-scission with the abstraction of carbon monoxide. Such a mechanism is known from the combustion chemistry of cyclopentadiene. The proposed mechanism of this reaction provides a framework for understanding the observed oscillatory kinetics.
- Valent, Ivan,Pribus, Marek,Novák, Filip,Plánková, Sylvia,Bla?ko, Jaroslav,Kubinec, Róbert,Almássy, Ambroz,Filo, Juraj,Sigmundová, Ivica,Sebechlebská, Táňa,Lawson, Thuy Bich,Noszticzius, Zoltán
-
p. 9669 - 9681
(2019/11/14)
-
- 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions
-
Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.
- Khosravi, Kaveh,Naserifar, Shirin
-
supporting information
p. 6584 - 6592
(2018/10/05)
-
- Graphene Oxide Promoted Oxidative Bromination of Anilines and Phenols in Water
-
The mildly acidic and oxidative nature of graphene oxide, with its large surface area available for catalytic activity, has been explored in aromatic nuclear bromination chemistry for the first time. The versatile catalytic activity of graphene oxide (GO) has been used to selectively and rapidly brominate anilines and phenols in water. The best results were obtained at ambient temperatures using molecular bromine in a protocol promoted by oxidative bromination catalyzed by GO; these transformations proceeded with 100% atom economy with respect to bromine and high selectivities for the tribromoanilines and -phenols. Reduced graphene oxide (r-GO) was observed to form after the second recycle (third use) of GO. This technique is also effective with N-bromosuccinimide (NBS) as the brominating reagent. In the case of NBS, reactions were instantaneous and the GO displayed excellent recyclability without any loss of activity over several cycles.
- Ghorpade, Prashant Vasantrao,Pethsangave, Dattatray Appasha,Some, Surajit,Shankarling, Ganapati Subray
-
p. 7388 - 7397
(2018/07/29)
-
- Complexes of cis-dioxomolybdenum(VI) with a chiral tetradentate tripodal-like ligand system: Syntheses, structures and catalytic activities
-
Racemic complexes with the general formula cis-[MoO2(bzacLn)] (1–4) (H2bzacLn?=?2-((4/5-R-2-hydroxyphenylamino)(pyridin-2-yl)methyl)-1-phenylbutane-1,3-dione, where n?=?1–4 for R?=?H, 5-Me, 5-Cl and 4-Me, respectively and 2Hs represent the dissociable phenolic proton and the active tertiary CH proton) have been synthesized in 75–82% yields by reacting [MoO2(bzac)2] (Hbzac?=?benzoylacetone) with the potentially N2O-donor 5,5-membered fused chelate rings forming Schiff bases 4/5-R-2-(2-pyridylaldimine)phenols (HLn; n?=?1–4 for R?=?H, 4-Me, 4-Cl and 5-Me, respectively) in hot methanol. The chiral ligand system (bzacLn)2?in 1–4 is formed via metal assisted Mannich-type addition of benzoylacetonate methine to the azomethine fragment of HLn. All four complexes have been characterized by elemental (CHN) analysis, solution conductivity, magnetic susceptibility, spectroscopic (IR, UV–Vis and NMR) and electrochemical measurements. The molecular structures of 1–3 have been established by single crystal X-ray crystallography. In each complex, the chiral (bzacLn)2?acts as a tetradentate, N2O2-donor, tripodal-like ligand system and along with the two mutually cis oxo groups forms a distorted octahedral N2O4coordination environment around the molybdenum(VI) center. All four complexes are diamagnetic and non-electrolytic. The infrared spectra are generally consistent with the structural formulas of 1–4. The electronic spectra of 1–4 in dimethylformamide display two strong absorption bands in the range 245–300?nm. The cyclic voltammograms of 1–4 in dimethylformamide exhibit a metal centered one-electron reduction response within ?0.64 to ?0.74?V. All these complexes (1–4) and the analogous cis-[MoO2(acacL1–4)] (5–8) synthesized from [MoO2(acac)2] (Hacac?=?acetylacetone) and HL1–4have been evaluated for their bromoperoxidase activities.
- Ghosh, Sabari,Kurapati, Sathish Kumar,Pal, Samudranil
-
-
- Green process development for the preparation of 2,6-dibromo-4-nitroaniline from 4-nitroaniline using bromide-bromate salts in an aqueous acidic medium
-
An organic solvent-free process for the preparation of 2,6-dibromo-4-nitroaniline, (an important intermediate in the synthesis of azo disperse dyes) from 4-nitroaniline using 2:1 bromide-bromate salts under an aqueous acidic medium at ambient conditions has been developed. The 2:1 bromide-bromate couple could be obtained by mixing pure NaBr/NaBrO3 salts or by adjusting the 5:1 mole ratio of NaBr/NaBrO3 (obtained in an aqueous solution as an intermediate from the bromine manufacture industry by a cold process) to 2:1 by the addition of a suitable oxidant. After completion of the reaction the product was purified by simple filtration and washing with water. The aqueous acidic filtrate was recycled up to five times without loss of purity and yield of the product. The method was extended to other aromatic substrates.
- Pappula, Venkatanarayana,Adimurthy, Subbarayappa
-
p. 90184 - 90187
(2016/10/07)
-
- Rapid and total bromination of aromatic compounds using TsNBr2 without any catalyst
-
N,N-Dibromo-p-toluenesulfonamide (TsNBr2) has been found to be a new reagent for bromination of aromatic compounds. The reaction is extremely fast and goes into completion instantaneously at ambient temperature to produce exclusively the corresponding polybrominated product. This procedure is applicable to various phenols, anisole, and anilines to give corresponding polybrominated compound as a single product in excellent yield.
- Saikia, Indranirekha,Chakraborty, Pranita,Sarma, Manas Jyoti,Goswami, Mridusmita,Phukan, Prodeep
-
p. 211 - 217
(2015/10/29)
-
- 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)
-
- A facile, regioselective and controllable bromination of aromatic amines using a CuBr2/Oxone system
-
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
-
p. 12091 - 12095
(2013/09/02)
-
- Green, mild and efficient bromination of aromatic compounds by HBr promoted by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane in water as a solvent
-
A combination of HBr and trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as a new and powerful oxidant was found effective for facile bromination of different aromatic compounds at room temperature in water as a green solvent. Mild reaction conditions, high selectivity and yield, high reaction rate and non-toxicity are some of the major advantages of this synthetic protocol.
- Khosravi, Kaveh,Kazemi, Samira
-
experimental part
p. 387 - 390
(2012/05/20)
-
- Regioselective bromination and iodination of aromatic substrates promoted by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane
-
Selective and efficient bromination and iodination of aromatic compounds by ammonium bromide and ammonium iodide, respectively, under promotion of trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane have been explored. Mild reaction conditions, high selectivity and yield, and high reaction rate are some of the major advantages of this synthetic method.
- Azarifar, Davood,Khosravi, Kaveh,Najminejad, Zohreh,Soleimani, Khadijeh
-
experimental part
p. 321 - 326
(2012/08/14)
-
- Trigonal rigid triphenols: Self-assembly and multicomponent lattice inclusion
-
The sterics introduced via methyl groups impart rigidity and inclusion behavior to trigonal C3-symmetric triphenol hosts H1-H4. Triphenol H1 is found to mimic the O-H...O hydrogen-bonded self-assembly of trimesic acid to yield porous honeycomb nets. It is found that 18-crown-6?H1 in turn binds guest molecules in the hexagonal voids to yield guest?guest?host multicomponent molecular crystals. The triphenol H2 and the homologous derivatives H3 and H4 are also found to crystallize with 18-crown-6 and other guests to yield multicomponent crystals, but in these cases the 18-crown-6 is found to serve as a spacer. While the structure of H2 is determined in its guest-free form, some of the inclusion compounds of triphenols lend themselves to crystal packings that are deciphered based on network topologies. The networks observed for H1-Tol and H3-C-B-Et are unique; in the latter, the crystal packing analysis reveals organization of molecules into a pattern that is reminiscent of borromean rings.
- Moorthy, Jarugu Narasimha,Natarajan, Palani,Bajpai, Alankriti,Venugopalan, Paloth
-
scheme or table
p. 3406 - 3417
(2012/04/04)
-
- An instant and facile bromination of industrially-important aromatic compounds in water using recyclable CaBr2-Br2 system
-
Various industrially-important brominated intermediates have been instantly synthesized using aq. CaBr2-Br2 system as an efficient and recyclable brominating reagent under aqueous conditions at room temperature without the need for metal catalysts or acidic additives. Structurally-diverse phenol and aniline derivatives with strong electron-withdrawing groups such as carboxylic, nitro and formyl show remarkable reactivity to the brominating reagent and brominated in 92-98% yield with high purity (>99%) in a very short reaction time. Organic solvent-free conditions, a feature of the green chemistry, were successively used not only for the reactions but also for the isolation of products at the end of the reaction. The recycling of HBr by its neutralization, thereby generating additional amounts of industrially-important CaBr2 has been designed and developed. The brominating reagent has been recycled and regenerated, and the process was repeated up to 4 cycles after the fresh batch using the regenerated brominating reagent having almost identical selectivity and isolated yields, which seems to be the most promising methodology from the viewpoint of the green approach to organic synthesis.
- Kumar, Lalit,Mahajan, Tanu,Agarwal
-
experimental part
p. 2187 - 2196
(2011/09/16)
-
- Identification of bromination products of chloro-substituted anilines in aqueous environment by gas chromatography
-
To reduce the detection limits of aniline and its various chloroderivatives (all isomers of mono- and dichloroanilines, 2,4,5 -, 2,4,6-, and 3,4,5-trichloroanilines, pentachloroaniline) in aqueous media we suggested bromination reaction, followed by gas chromatographic definition bromo derivatives of chloroanilines on a selective electron capture detector. To identify the products of bromination of chloroaniline in combination with mass-spectrometric data we used chromatographic retention indices on standard nonpolar polydimethylsiloxane stationary phase that was determined for 50 compounds in this class. The technique of identifying bromoderivatives of chloroaniline in water was developed at the gas-chromatographic analysis in the selective electron capture detector. To improve the reliability of the identification of additional bromoderivatives of chloroanilines we obtained their trifluoroacetyl derivatives.
- Gruzdev,Filippova,Zenkevich,Kondratenok
-
experimental part
p. 1748 - 1759
(2012/02/15)
-
- Regioselective bromination of organic substrates by LDH-CO3 2--Br- promoted by V2O5-H 2O2
-
An efficient, fast, simple, mild, and selective monobromination of aromatic compounds, with high para-selectivity, is reported. The catalytic system is readily prepared from a Mg-Al-layered double hydroxide-CO3 2--Br- (LDH-CO32--Br-) as the source of bromide, V2O5 as a promoter and hydrogen peroxide as the oxidant. The use of hydrogen peroxide as a synthetically useful oxidizing agent is reported for generating electrophilic bromine in situ from easily available KBr as a bromine source, to brominate electron rich aromatic compounds, employing LDH-CO32--Br3- as the phase-transfer catalyst. The phase-transfer catalyst leads to nearly complete bromination in 3 h at room temperature with high selectivity. The reaction rate of p-bromoanisole and p-bromotoluene formation by LDH-CO 32--Br3- in a triphasic system was studied. The heterogeneity of the reaction system facilitates the recovery and recycling of the catalyst, and the reagent components are environmentally acceptable. The catalyst, LDH-CO32--Br3 -, and its precursors, LDH-CO32--Br- and LDH-CO32-, were characterized by powder XRD, FT-IR and UV-vis spectroscopy.
- Ghiaci,Sedaghat,Ranjbari,Gil
-
experimental part
p. 18 - 26
(2011/01/05)
-
- Effect of structural factors and solvent nature in bromination of anilines
-
Reaction of electrophilic bromination of aniline containing various ortho, meta, and para substituents in the aromatic ring was studied. The optimal conditions for synthesis of mono-, di-, tri-, and tetrabromo derivatives of aniline and brominated analog of Aniline Black were found.
- Bagmanov
-
p. 1570 - 1576
(2011/06/20)
-
- Regioselective bromination of activated aromatic substrates with a ZrBr4/diazene mixture
-
A regioselective method for the bromination of phenols, ethers and anilines using a ZrBr4/diazene mixture is described. The reaction takes place under mild reaction conditions and the bromine atom adds first at the para unsubstituted position with respect to the OH, OR or NR2 group of the activated aromatic substrate. Less reactive compounds such as toluene, phenyl acetate, benzonitrile and trifluoromethylbenzene remain intact under the same conditions.
- Stropnik, Tadej,Bombek, Sergeja,Ko?evar, Marijan,Polanc, Slovenko
-
p. 1729 - 1733
(2008/09/18)
-
- 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)
-
- Regioselective aromatic electrophilic bromination with dioxane dibromide under solvent-free conditions
-
Highly regioselective ring bromination of aromatic compounds has been accomplished with high yields and good purity using dioxane dibromide (DD) under solvent-free conditions. Notable features of this methodology include operational simplicity, rapid reactions, excellent control over the degree of bromination, and tolerance of various functional groups during the reaction. Copyright Taylor & Francis Group, LLC.
- Chaudhuri, Subrata Kumar,Roy, Sanchita,Saha,Bhar, Sanjay
-
p. 581 - 585
(2007/10/03)
-
- Green synthesis of tetraalkylammonium tribromide using cerium(IV) ammonium nitrate (CAN) as oxidant
-
Cerium(IV) ammonium nitrate (CAN) mediates oxidation of tetraalkylammonium bromide to tetraalkylammonium tribromide in greener reaction conditions using water as solvent. The procedure is simple, convenient, and environmentally benign for the synthesis of tetraalkylammonium tribromide with great yields. Copyright Taylor & Francis Group, LLC.
- Borah, Ruli,Thakur, Ashim Jyoti
-
p. 933 - 939
(2007/10/03)
-
- Site directed nuclear bromination of aromatic compounds by an electrochemical method
-
Direct bromination of a wide range of aromatic compounds possessing electron-donating groups, such as methoxy, hydroxy or amino groups, have been carried out by two-phase electrolysis. This electrochemical method results in high yields (70-98%) of monobromo compounds and usually with high regioselectivity (>95%) for the para position.
- Raju,Kulangiappar,Anbu Kulandainathan,Uma,Malini,Muthukumaran
-
p. 4581 - 4584
(2007/10/03)
-
- Polymer-supported organotin reagents for regioselective halogenation of aromatic amines
-
(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
-
p. 2870 - 2873
(2007/10/03)
-
- A new method for the oxybromination of aromatic compounds with copper(II)bromide and potassium dichromate
-
A new and mild method for oxybromination of aromatic compounds with CuBr2 and K2Cr2O7 in HOAC is reported. Copyright Taylor & Francis Inc.
- Badri, Rashid,Shushizadeh, Mohammad Reza
-
p. 533 - 536
(2007/10/03)
-
- 1-Benzyl-4-aza-1-azoniabicyclo[2.2.2] octane tribromide as a highly reactive brominating agent for aniline derivatives
-
Reaction of anilines with 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane tribromide (3) in the presence of CaCO3 in small amounts of methanol gave brominated aromatic amines in good yields at room temperature. The isolation of products is straightforward.
- Hajipour,Imanieh,Pourmousavi
-
p. 4597 - 4604
(2007/10/03)
-
- Photoreaction of nitrobenzenes with hydrobromic acid
-
Nitrobenzene and three derivatives (3-CO2H, 3-OH, and 4-OH) give tribromoanilines when irradiated in hydrobromic acid.
- McIntyre, Brian P.,Coleman, Brian D.,Wubbels, Gene G.
-
p. 7709 - 7711
(2007/10/03)
-
- Environmentally benign chlorination and bromination of aromatic amines, hydrocarbons and naphthols
-
A simple and efficient procedure for chlorination and bromination of aromatic amines, hydrocarbons and naphthols by the action of aqueous hydrohalic acid and hydrogen peroxide is described. This environmentally clean and safe procedure involves in situ generation of the active halogen and its uncatalyzed reaction with the substrates in this study.
- Vyas, Punita V.,Bhatt, Anjani K.,Ramachandraiah, Gadde,Bedekar, Ashutosh V.
-
p. 4085 - 4088
(2007/10/03)
-
- Phase-Vanishing Methodology for Efficient Bromination, Alkylation, Epoxidation, and Oxidation Reactions of Organic Substrates
-
(Matrix presented) In cases where both reactants in a phase-vanishing reaction are less dense than the fluorous phase, an alternative to the U-tube method is to employ a solvent with greater density than the fluorous phase, such as 1,2-dibromoethane. This modification has been successfully applied to the methylation of a phenol derivative with dimethyl sulfate and to the m-CPBA-induced epoxidation of alkenes, N-oxide formation from nitrogen-containing compounds, and S-oxide or sulfone formation from organic sulfides.
- Jana, Nirmal K.,Verkade, John G.
-
p. 3787 - 3790
(2007/10/03)
-
- Oxidative halogenation of aromatic compounds with metal halides and sodium bismuthate
-
A new mild and efficient method for aromatic halogenation with a wide variety of halides in the presence of sodium bismuthate NaBO3 in AcOH is reported. Metal halides of groups Ia, IIa, IIIa, IVa, Va, and the first row of transition elements are suitable for this method.
- Muathen, Hussni A.
-
p. 164 - 168
(2007/10/03)
-
- Pyridinium dichlorobromate: A new stable brominating agent for aromatic compounds
-
Pyridinium dichlorobromate (PyHBrCl2, 1) is a new example of iminium-trihalide complexes. The compound is prepared from pyridine and chlorine in the presence of aqueous hydrogen bromide. The crystalline trihalide is quite stable and acts as a safe source of positive bromine. It shows a remarkable reactivity towards aromatic compounds compared with other bromine complexes. It is also considered as a potential source for bromine chloride BrCl.
- Muathen, Hussni A.
-
p. 169 - 171
(2007/10/03)
-
- Mild and regioselective oxidative bromination of anilines using potassium bromide and sodium perborate
-
The selective monobromination of various deactivated anilines using potassium bromide and sodium perborate as oxidant has been achieved. The use of ammonium molybdate as catalyst accelerates the rate of reaction but is not essential to obtain good yields and high selectivities. (C) 2000 Elsevier Science Ltd.
- Roche, Didier,Prasad, Kapa,Repic, Oljan,Blacklock, Thomas J.
-
p. 2083 - 2085
(2007/10/03)
-
- An environmentally benign synthesis of organic ammonium tribromides (OATB) and bromination of selected organic substrates by tetrabutylammonium tribromide (TBATB)
-
Stable crystalline organic ammonium tribromides (OATB), like Me4NBr3, Et4NBr3, Bu4NBr3, cetyltrimethylammonium tribromide, PyHBr3, can be readily synthesised from the reaction of the corresponding bromides with V2O5 and aqueous H2O2. Typically, TBATB, Bu4NBr3, brominates a variety of organic substrates rather easily under mild conditions. An activated aromatic ring is selectively brominated in the presence of an olefinic double bond.
- Chaudhuri, Mihir K.,Khan, Abu T.,Patel, Bhisma K.,Dey, Deepa,Kharmawophlang, Wancydora,Lakshmiprabha,Mandal, Gagan C.
-
p. 8163 - 8166
(2007/10/03)
-
- Electrophilic Aromatic Bromination Using Bromodimethylsulfoniuin Bromide Generated in Situ
-
It has been shown that bromodimethylsulfonium bromide, generated in situ by treating dimethyl sulfoxide with aqueous hydrobromic acid, is a milder and more selective reagent for electrophilic aromatic bromination than elemental bromine.
- Majetich, George,Hicks, Rodgers,Reister, Steven
-
p. 4321 - 4326
(2007/10/03)
-
- Selectivity in bromination of aniline and N-substituted anilines encapsulated in β-cyclodextrin
-
In contrast to the conventional bromination, aniline and N-methylaniline encapsulated in β-Cyclodextrin (β-CD) give ortho-bromoaniline and parabromo-N-methylaniline respectively in larger yield. The results are explained on the basis of mode of complexation between β-CD and anilines.
- Velusamy, Ponnusamy,Pitchumani, Kasi,Srinivasan, Chockalingam
-
p. 3487 - 3496
(2007/10/03)
-
- Reaction of Aromatic and Unsaturated Compounds with the Potassium Permanganate/HCI (HBr) Acetonitrile Reagent
-
Addition of hydrochloric or hydrobromic acid to a solution of potassium permanganate in acetonitrile produced a homogeneous mixture, which is suitable for laboratory chlorination or bromination, respectively. Aromatic compounds more reactive than alkylbenzenes can be chlorinated or brominated without additional catalyst. Alkenes and alkynes give the corresponding vicinal dihaloalkanes and vinyl halides. All reactions complete within two hours under mild condition (25-60 °C) with excellent to moderate yields.
- Liu, Lilian Kao,Lin, Ching-Shan
-
-
- Efficient Catalysis of Hydrodediazoniations in Dimethylformamide
-
For hydrodediazoniations (the replacement of a diazo group by hydrogen) in DMF, several substances act as catalysts through their ability to serve as electron donors and initiate free-radical reactions.A general procedure has been developed in which FeSO4 speeds the conversion and leads to higher yields.Trapping experiments demonstrated the presence of free-radical intermediates.N,N-Dimethylacetamide was found to rival DMF as a source of hydrogen atoms.
- Wassmundt, Frederick W.,Kiesman, William F.
-
p. 1713 - 1719
(2007/10/02)
-
- Regiospecific fragmentation of benzene derivatives: Synthetic and analytical applications
-
The cycloadducts formed from arenes and tetrachloro- and tetrafluorobenzyne have been shown to undergo specific addition-fragmentation reactions. These sequences are both simple syntheses of arenes with unusual substitution patterns and a convenient alternative to the other methods currently available for assaying the isotopic distribution in [14C]-labelled benzene derivatives.
- Hales, Neil J.,Heaney, Harry,Hollinshead, John H.,Ley, Steven V.
-
p. 7755 - 7776
(2007/10/02)
-
- FORMATION OF ACETALS AND CLEAVAGE OF THE FIVE-MEMBERED RING IN THE BROMINATION OF ISATIN IN ALCOHOLS
-
Bromination of isatin (I) in alcohols affords in good yield 5,7-dibromo-3,3-dialkoxy-2-indolinones (IIIa and IIIb) which arise by reaction catalysed with hydrogen bromide liberated in the bromination.The reaction affords also minor amounts of 2,4,6-tribromoaniline (IV) formed by splitting off of two carbon atoms from the isatin five-membered ring.
- Gasparic, Jiri,Vontor, Tomas,Lycka, Antonin,Snobl, Dobroslav
-
p. 2963 - 2966
(2007/10/02)
-
- BROMINATION OF ANILINES BY BENZYLTRIPHENYLPHOSPHONIUM TRIBROMIDE
-
Anilines and benzyltriphenylphosphonium tribromide in dichloromethane and methanol medium in the presence of sodium bicarbonate react within a few minutes at room temperature to give the corresponding polybromoanilines in good yields.
- Xin-teng, Ding,Guo-bin, Liu
-
p. 1261 - 1266
(2007/10/02)
-
- Halogenation Using Quaternary Ammonium Polyhalides. VI. Bromination of Aromatic Amines by Use of Benzyltrimethylammonium Tribromide
-
The reaction of aromatic amines with benzyltrimethylammonium tribromide in dichloromethane-methanol containing calcium carbonate powder for 0.5 h at room temperature gave bromo-substituted aromatic amines in good yields.
- Kajigaeshi, Shoji,Kakinami, Takaaki,Inoue, Kazuhisa,Kondo, Manabu,Nakamura, Hiroko,et al.
-
p. 597 - 599
(2007/10/02)
-