- New procedure for the highly regioselective aerobic bromination of aromatic compounds using copper-based nanocatalyst
-
A new procedure for the highly regioselective aerobic bromination of aromatic compounds in the presence of copper-based nanoparticles (CuO/ZnO nanocatalyst) under reflux condition is described. Mechanistic parameters are discussed and the plausible mechanism is proposed. Recyclability of the CuO/ZnO nanocatalyst has also been explored upon aerobic bromination of aromatic compounds.
- Albadi, Jalal,Jalali, Mehdi
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p. 234 - 239
(2020/02/29)
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- Regioselective monobromination of phenols with KBr and ZnAl–BrO3?–layered double hydroxides
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The regioselective mono-bromination of phenols has been successfully developed with KBr and ZnAl–BrO3?–layered double hydroxides (abbreviated as ZnAl–BrO3?–LDHs) as brominating reagents. The para site is much favorable and the ortho site takes the priority if para site is occupied. This reaction featured with excellent regioselectivity, cheap brominating reagents, mild reaction condition, high atom economy, broad substrate scope, and provided an efficient method to synthesize bromophenols.
- Wang, Ligeng,Feng, Chun,Zhang, Yan,Hu, Jun
-
supporting information
(2020/02/22)
-
- 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)
-
- o-xylylene bis(triethyl ammonium tribromide) as a mild and recyclable reagent for rapid and regioselective bromination of anilines and phenols
-
Background: o-Xylylene bis(triethyl ammonium tribromide) (OXBTEATB) as a recyclable and high bromine containing di-(tribromide) reagent has been employed for the bromination of various organic substrates such as phenol and aniline or its derivatives. This catalyst can be recovered and reused several times. Methods: Aryl bromides shown in Table 1, were easily produced from bromination of aromatic compounds by OXBTEATB. This high-yield process lets the reagents to be recycled and reused. Results: As shown in Table 1, substituted anilines, phenols and β-naphthol were found to be the most reactive and immediately converted to the corresponding mono-brominated products by OXBTEATB. Conclusion: OXBTEATB can be considered a solidified bromine. This novel reagent has variable solubility in different polar protic and aprotic solvents but insoluble in non-polar aprotic solvent. Subsequently, OXBTEATB can be recognized as a more useful brominating and regioselective catalyst than the liquid bromine.
- Hemati, Roya,Shahvelayati, Ashraf S.,Yadollahzadeh, Khadijeh
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p. 682 - 687
(2018/07/14)
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- Synthesis, kinetics, and mechanism of bromophenols by N-bromophthalimide in aqueous acetic acid
-
The kinetics and mechanism of bromination of phenol and its substituents, viz. 4-chlorophenol, 4-bromophenol, 4-methylphenol, and 4-methoxyphenol by N-bromophthalimide (NBP) in the presence of mercuric acetate in the temperature range of 303–318?K in aqueous acetic acid medium have been investigated. The reaction follows first-order dependence on [NBP] and fractional order dependence of rate on [Phenol]. The activation parameters have been evaluated, and based on the observed kinetic results the probable mechanism has been proposed. Observed kinetic features and Hammett's reaction constant (ρ) suggests that bromination occurs through electrophilic substitution of bromonium ion (Br+) into the aromatic ring in the transition state. Large negative entropy of activation values probably suggests the rigid nature of transition state.
- Anjaiah, Birla,Prameela, Kethavath,Srinivas, Pabba,Rajanna, Kamatala Chinna
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p. 804 - 812
(2018/09/11)
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- Expedient Access to 2-Benzazepines by Palladium-Catalyzed C?H Activation: Identification of a Unique Hsp90 Inhibitor Scaffold
-
Bioactive 2-benzazepines were accessed in an atom- and step-economical manner through a versatile palladium-catalyzed C?H activation strategy. The C?H arylation required low catalyst loading and a mild base, which was reflected by a broad scope and high functional-group tolerance. The benzotriazolodiazepinones were identified as new heat shock protein 90 (Hsp90) inhibiting lead compounds, with considerable potential for anti-cancer applications.
- Virelli, Matteo,Moroni, Elisabetta,Colombo, Giorgio,Fiengo, Lorenzo,Porta, Alessio,Ackermann, Lutz,Zanoni, Giuseppe
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supporting information
p. 16516 - 16520
(2018/10/25)
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- Ultrasonically assisted halogenation of aromatic compounds using isoquinolinium bound hypervalent chromium and tetrabutylammonium halides in PEG-600 solutions under acid free and solvent-free conditions
-
Isoquinolinium bound Cr(VI) reagents like isoquinolinium dichromate (IQDC) and isoquinolinium chlorochromate (IQCC) have been successfully accomplished as efficient reagents for oxidative halogenation of aromatic compounds using tetrabutylammonium halide (TBAX) as halogenating agents in aqueous polyethylene glycol (PEG-600) under acid free conditions. Tetrabutylammonium bromide (TBAB) has been used for bromination and tetrabutylammonium iodide (TBAI) for iodination. The halogenation reactions that occurred smoothly in 2 to 7 h under conventional conditions are accelerated magnificently under sonication with few minutes (25 to 70 min) of reaction time and fairly good yields. The reactions occurred at moderate temperature under mild and environmentally safe conditions with simple work up.
- Sambashiva Rao,Ramesh, Kola,Rajanna,Chakrvarthi
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p. 1892 - 1896
(2018/07/10)
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- Polymer-anchored [Fe(III)Azo] complex: An efficient reusable catalyst for oxidative bromination and multi-components reaction for the synthesis of spiropiperidine derivatives
-
A heterogeneous catalyst was prepared by attaching Fe(III) into organically modified chloromethylated polytstyrene and characterized by AAS, IR, PXRD, TG-DTA, UV–Vis, and SEM studies. In presence of H2O2 and KBr as bromine source, the catalyst showed remarkably high conversion with para-selectivity towards the oxidative bromination reaction in acetic acid medium. The catalyst was also very active and highly efficient for the production of spiropiperidine derivatives through multi-component reaction in isopropyl alcohol at room temperature. The catalyst was not leached during the catalytic reactions, moreover, after five cycles the catalytic activity and selectivity of the catalyst were not decreased very significantly.
- Khatun, Resmin,Biswas, Surajit,Ghosh, Swarbhanu,Islam, Sk. Manirul
-
-
- Macrocyclic Modulators of the Ghrelin Receptor
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The present invention provides novel conformationally-defined macrocyclic compounds that have been demonstrated to be selective modulators of the ghrelin receptor (growth hormone secretagogue receptor, GHS-R1a and subtypes, isoforms and variants thereof). Methods of synthesizing the novel compounds are also described herein. These compounds are useful as agonists of the ghrelin receptor and as medicaments for treatment and prevention of a range of medical conditions including, but not limited to, metabolic and/or endocrine disorders, gastrointestinal disorders, cardiovascular disorders, obesity and obesity-associated disorders, central nervous system disorders, genetic disorders, hyperproliferative disorders and inflammatory disorders.
- -
-
Paragraph 0469
(2018/05/03)
-
- Photoinduced Synthesis of Dibenzofurans: Intramolecular and Intermolecular Comparative Methodologies
-
The SRN1 reaction has been used as a powerful tool for the synthesis of heterocycles, and only a few studies about photoinduced intramolecular cyclization to generate a new C-O bond by a radical pathway have been reported. This work introduces two strategies for the synthesis of substituted dibenzofurans by electron transfer (eT) reactions. The first one is a three-step process that comprises bromination of o-arylphenols, Suzuki-Miyaura cross-coupling and photoinduced cyclization in order to obtain the above-mentioned products. The second one is a metal-free procedure and does not require any photocatalyst. Different solvents were tested, and the yields ranged from low to moderate. A comparison was established between both methodologies, showing that the second one is the most suitable for the synthesis of dibenzofurans.
- Camargo Solórzano, Patricia,Brigante, Federico,Pierini, Adriana B.,Jimenez, Liliana B.
-
supporting information
p. 7867 - 7877
(2018/06/11)
-
- Inhibition of mutated isocitrate dehydrogenase 1 in cancer
-
Background: R132H mutation of isocitrate dehydrogenase 1 (IDH1) is found in ~75% of low-grade gliomas and secondary glioblastomas as well as in several other types of cancer. More chemotypes of inhibitors of IDH1(R132H) are therefore needed. Objective: The study aimed to develop a new class of IDH1(R132H) inhibitors as potent antitumor agents. Method: A biochemical assay was developed to find inhibitors of IDH1(R132H) mutant enzyme. Chemical synthesis and structure-activity relationship studies were used to find compounds with improved potency. Antitumor activities of selected compounds were evaluated. Results: A series of aromatic sulfonamide compounds was found to be novel, potent inhibitors of IDH1(R132H) with Ki values as low as 0.6 μM. Structure-activity relationships of these compounds are discussed. Enzyme kinetics studies showed that one compound is a competitive inhibitor against the substrate α-KG and a non-competitive inhibitor against the cofactor NADPH. Several inhibitors were found to have no activity against wild-type IDH1, showing a high selectivity. Two potent inhibitors exhibited strong activity against proliferation of BT142 glioma cells with IDH1 R132H mutation, while these compounds did not significantly affect the growth of glioma cells without IDH1 mutation. Conclusion: This novel series of IDH1(R132H) inhibitors have potential to be further developed for the treatment of glioma with IDH1 mutation.
- Wu, Fangrui,Cheng, Gang,Yao, Yuan,Jiang, Hong,Song, Yongcheng,Kogiso, Mari,Li, Xiao-Nan
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p. 715 - 724
(2018/11/21)
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- Chemoselectivity in the Kosugi-Migita-Stille coupling of bromophenyl triflates and bromo-nitrophenyl triflates with (ethenyl)tributyltin
-
Kosugi-Migita-Stille cross coupling reactions of (ethenyl)tributyltin with all isomeric permutations of bromophenyl triflate and bromo-nitrophenyl triflate were examined in order to determine the chemoselectivity of carbon-bromine versus carbon-triflate bond coupling under different reaction conditions. In general, highly selective carbon-bromine bond cross couplings were observed using for example bis(triphenylphosphine)palladium dichloride (2 mol-%) in 1,4-dioxane at reflux. In contrast, reactions using the same pre-catalyst but in the presence of a three-fold excess of lithium chloride in N,N-dimethylformamide at ambient temperature were in most cases selective for coupling at the carbon-triflate bond. Overall, isolated yields and the selectivity for carbon-bromine bond coupling were significantly higher compared to carbon-triflate bond coupling.
- Ansari, Nurul N.,Cummings, Matthew M.,S?derberg, Bj?rn C.G.
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p. 2547 - 2560
(2018/04/20)
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- The synthesis of 1,2-ethanediylbis(triphenylphosphonium) ditribromide as a new brominating agent in the presence of solvents and under solvent-free conditions
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Abstract: 1,2-Ethanediylbis(triphenylphosphonium) ditribromide was quantitatively prepared and used for the bromination of anilines and phenols in the presence of a mixed solvent system (DCM/MeOH 2:1) and also under solvent-free conditions. This new ionic liquid has advantages over similar brominating agents in terms of short reaction time, simple workup, regioselectivity and high yields. Single-crystal X-ray analysis of title salt revealed that the bistriphenylphosphonium cation is organized around an inversion center located at the center of the –CH2–CH2– bridge and the two triphenylphosphine segments are anti with respect to one another. All the tribromide anions adopt a linear geometry with different Br–Br–Br bond angles for each anion. Graphical Abstract: [Figure not available: see fulltext.]
- Salmasi, Reihaneh,Gholizadeh, Mostafa,Salimi, Alireza,Garrison, Jered C.
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p. 2019 - 2028
(2016/09/16)
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- Isoquinolinium Dichromate and Chlorochromate as Efficient Catalysts for Oxidative Halogenation of Aromatic Compounds under Acid-Free Conditions
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Isoquinolinium dichromate and isoquinolinium chlorochromate were found as efficient catalysts to trigger oxidative bromination and iodination of aromatic hydrocarbons with KBr/KI and KHSO4 under acid-free conditions. Reaction times reduced highly significantly under sonication, followed by corresponding mono bromo derivatives in very good yield with high regioselectivity.
- Rao, A. Sambashiva,Rajanna,Reddy, K. Rajendar,Kulkarni, Subhash
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p. 832 - 837
(2016/02/12)
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- Novel method for preparing Eltrombopag intermediate
-
The invention provides a method for preparing a compound shown as the formula I (please see the formula in the description). The method specifically comprises the following steps that 1, a compound shown as the formula (II) (please see the formula in the description) reacts with a compound shown as formula (V) (please see the formula in the description) under the alkaline condition to generate a compound shown as the formula (III) (please see the formula in the description); 2, the compound shown as the formula (III) (please see the formula in the description) reacts with a compound shown as the formula (VI) (please see the formula in the description) under the alkaline condition in the presence of palladium carbon to generate a compound shown as the formula (IV) (please see the formula in the description); 3, the compound shown as the formula (IV) (please see the formula in the description) reacts in the presence of palladium carbon and a hydrogen source under the alkaline condition to generate the compound shown as the formula (I) (please see the formula in the description). According to the method, design is ingenious, protecting group removal, dechlorination and nitro reduction are together completed in the final hydrogenation process, and the purity of the obtained compound shown as the formula (I) (please see the formula in the description) is high; the most important thing is that compared with other Suzuki coupling agents, cost of palladium carbon is lower, a source of palladium carbon is wide and easy to obtain, palladium carbon can be directly recycled and reused after being simply filtered and separated, and therefore the material cost is greatly reduced; meanwhile, emission of three wastes is reduced, and the method is quite suitable for industrialized production.
- -
-
Paragraph 0059-0061
(2017/04/29)
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- CANCER TREATMENT METHOD
-
A method of treating cancer is described including administration of a 4-quinazolineamine and at least one other anti-neoplastic agent as well as a pharmaceutical combination including the 4-quinazolineamines.
- -
-
Paragraph 0167-0168
(2016/03/12)
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- Aerobic oxidation and oxidative bromination in aqueous medium using polymer anchored oxovanadium complex
-
Polymer anchored oxovanadium catalyst was synthesized and characterized. Its catalytic activity was evaluated for the oxidation of various primary and secondary alcohols with molecular oxygen under mild reaction conditions. This catalyst was also effective for the oxidative bromination reaction of organic substrates with 90-100% selectivity of mono substituted products with H 2O2/KBr at room temperature. The above reactions require low temperature, short time period and most importantly all the above reactions occur in aqueous medium. The developed catalyst can be facilely recovered and reused six times without significant decrease in activity and selectivity. 2014 Elsevier B.V. All rights reserved.
- Islam, Sk. Manirul,Molla, Rostam Ali,Roy, Anupam Singha,Ghosh, Kajari,Salam, Noor,Iqubal, Md. Asif,Tuhina
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p. 169 - 178
(2014/05/06)
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- A practical nickel-catalyzed reductive alkylation of amidophenyl bromides
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A modified Weix's reductive coupling for alkylation of amidoaryl bromides based on Ni(COD)2 precatalyst and 2,2′-dipyridyl ligand was developed. This reaction is reliable for amidophenyl bromides and gives yields up to 87%, and is potentially useful in the synthesis of amidophenyl-containing molecules.
- Liu, Xuge,Yang, Zhilin,Li, Ya-Min,Yang, Fan,Feng, Liang,Wang, Nengzhong,Ma, Debiao,Chang, Kwen-Jen,Shen, Yuehai
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p. 9522 - 9529
(2015/03/04)
-
- A practical approach for regioselective mono-nitration of phenols under mild conditions
-
Cu(NO3)2.3H2O was demonstrated to be an efficient, regioselective and inexpensive nitrating reagent for the synthesis of mono-nitro substituted phenolic compounds. 12 examples of different phenols were examined. Good yields (67-90%) have been achieved. ARKAT-USA, Inc.
- Chen, Ling-Yan,Liu, Tao,Zhou, Xiaokun,Sun, Zhihua
-
-
- Poly(4-vinylpyridinium bromochromate): An efficient reagent for bromination of aromatic compounds
-
A simple and efficient method for the bromination of various aromatic compounds by using poly(4-vinylpyridinium bromochromate) is reported. This method has several advantages such as good selectivity between ortho and para positions of aromatic compounds, simple workup, short reaction times, and high yields of the products.
- Albadi, Jalal,Tajik, Hassan,Keshavarz, Mosadegh,Abedini, Masoumeh
-
p. 179 - 181
(2013/07/27)
-
- Dialkylimidazole inhibitors of Trypanosoma cruzi sterol 14α-demethylase as anti-Chagas disease agents
-
New dialkylimidazole based sterol 14α-demethylase inhibitors were prepared and tested as potential anti-Trypanosoma cruzi agents. Previous studies had identified compound 2 as the most potent and selective inhibitor against parasite cultures. In addition, animal studies had demonstrated that compound 2 is highly efficacious in the acute model of the disease. However, compound 2 has a high molecular weight and high hydrophobicity, issues addressed here. Systematic modifications were carried out at four positions on the scaffold and several inhibitors were identified which are highly potent (EC50 1 nM) against T. cruzi in culture. The halogenated derivatives 36j, 36k, and 36p, display excellent activity against T. cruzi amastigotes, with reduced molecular weight and lipophilicity, and exhibit suitable physicochemical properties for an oral drug candidate.
- Suryadevara, Praveen Kumar,Racherla, Kishore Kumar,Olepu, Srinivas,Norcross, Neil R.,Tatipaka, Hari Babu,Arif, Jennifer A.,Planer, Joseph D.,Lepesheva, Galina I.,Verlinde, Christophe L.M.J.,Buckner, Frederick S.,Gelb, Michael H.
-
supporting information
p. 6492 - 6499
(2013/11/19)
-
- Polymer-anchored Cu(II) complex as an efficient catalyst for selective and mild oxidation of sulfides and oxidative bromination reaction
-
A new polymer-anchored Cu(II) complex has been tested for the oxidation of sulfides and in oxidative bromination reaction with hydrogen peroxide as oxidant. Sulfides have been selectively oxidized to corresponding sulfoxides in excellent yields and in presence of KBr as bromine source, organic substrates have been selectively converted to mono bromo substituted compounds. The polymer-anchored Cu(II) catalyst could be easily recovered by simple filtration and reused more than six times without appreciable loss of its initial activity. Graphical Abstract: [Figure not available: see fulltext.]
- Islam, Sk. M.,Roy, Anupam Singha,Mondal, Paramita,Salam, Noor,Paul, Sumantra
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p. 225 - 233
(2013/03/13)
-
- Green halogenation of aromatic heterocycles using ammonium halide and hydrogen peroxide in acetic acid solvent
-
The green generation of X+ (X = Br, I) using hydrogen peroxide in aqueous acetic acid allows access to aromatic heterocyclic halides in yields and purities comparable to syntheses employing N-bromosuccinimide. In activated and unsubstituted thiophene rings, regioselectivity is quantitative for positions α to the sulfur; pyrroles also give quantitative reactions, at least initially. Deactivated rings, including furans and thiazoles, as well as thiophenes with strongly electron-withdrawing groups showed little to no reactivity under the conditions investigated. The reaction shows remarkable functional group tolerance (to alcohol, nitro, alkyl, halo, and carbonyl groups), as shown through reaction with substituted phenols. In all bromination reactions, reaction yields and regiochemistry were very similar to reactions involving N-bromosuccinimide in tetrahydrofuran solvent.
- D'Aleo, Danielle N.,Allard, Sheena R.,Foglia, Cassandra C.,Parent, Shawna L.M.,Rohr, David J.,Gottardo, Christine,MacKinnon, Craig D.
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p. 679 - 683
(2013/08/23)
-
- 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
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experimental part
p. 387 - 390
(2012/05/20)
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- 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)
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- Selective oxidation of sulfides and oxidative bromination of organic substrates catalyzed by polymer anchored Cu(II) complex
-
A new polymer-anchored Cu(II) complex has been synthesized and characterized. The catalytic performance of the complex has been tested for the oxidation of sulfides and in oxidative bromination reaction with hydrogen peroxide as the oxidant. Sulfides have been selectively oxidized to the corresponding sulfoxides in excellent yields and in the presence of KBr as the bromine source, organic substrates have been selectively converted to mono bromo substituted compounds using polymer-anchored Cu(II) catalyst. This catalyst showed excellent catalytic activity, high selectivity, and recyclability. The polymer-anchored Cu(II) catalyst could be easily recovered by filtration and reused more than five times without appreciable loss of its initial activity.
- Islam,Roy, Anupam Singha,Mondal, Paramita,Tuhina, Kazi,Mobarak, Manir,Mondal, John
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supporting information; experimental part
p. 127 - 131
(2012/01/17)
-
- Synthesis, catalytic oxidation and oxidative bromination reaction of a reusable polymer anchored oxovanadium(IV) complex
-
Polymer anchored oxovanadium catalyst was synthesized and characterized. The solid catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Its catalytic activity was evaluated for the oxidation of various alkenes, sulfides and aromatic alcohols with 30% H2O2 under mild reaction conditions. This catalyst was also effective for the oxidative bromination reaction of organic substrates with 80-100% selectivity of mono substituted products with H2O2/KBr at room temperature. The above reactions require minimum amount of H2O2, short time period and most importantly all the above reactions occur in aqueous medium. The developed catalyst can be facilely recovered and reused six times without significant decrease in activity and selectivity. This result confirms that the polymer anchored complex was not leached during the reaction, suggesting the true heterogeneous nature of the catalyst.
- Islam, Sk. Manirul,Roy, Anupam Singha,Mondal, Paramita,Salam, Noor
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experimental part
p. 38 - 48
(2012/05/21)
-
- 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
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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)
-
- Regioselective and high-yielding bromination of phenols and anilins using N-bromosaccharin and amberlyst-15
-
A regioselective and facile conversion method for bromination of anilines and phenols using N-bromosaccharine in the presence of a catalytic amount of Amberlyst-15 lead to enhancement of the reaction rate and yielded brominated products in good to excellent yields and short reaction times.
- Baharfar,Alinezhad,Azimi,Salehian
-
experimental part
p. 863 - 865
(2012/04/23)
-
- Nitration of phenolic compounds and oxidation of hydroquinones using tetrabutylammonium chromate and dichromate under aprotic conditions
-
In this work, we have reported a mild, efficient and selective method for the mononitration of phenolic compounds using sodium nitrite in the presence of tetrabutylammonium dichromate (TBAD) and oxidation of hydroquinones to quinones with TBAD in CH2Cl2. Using this method, high yields of nitrophenols and quinones were obtained under neutral aprotic conditions. Tetrabutylammonium chromate (TBAC) can also be used as oxidant at same conditions. Indian Academy of Sciences.
- Pourali, Ali Reza,Goli, Arezou
-
scheme or table
p. 63 - 67
(2012/01/13)
-
- Efficient, rapid, and regioselective bromination of phenols and anilines with N-bromosaccharin using tungstophosphoric acid as a heterogeneous recyclable catalyst
-
A simple, efficient, and rapid method for high-yielding regioselective mono bromination of phenols and anilines has been achieved by treatment with N-bromasaccharin in the presence of a catalytic amount of tungstophosphoric acid. Copyright Taylor & Francis Group, LLC.
- Alinezhad, Heshmatollah,Tavakkoli, Sahar Mohseni,Salehian, Fatemeh
-
experimental part
p. 3226 - 3232
(2010/12/24)
-
- An efficient regioselective NBS aromatic bromination in the presence of an ionic liquid
-
A simple, efficient, and rapid method was developed for high-yielding regioselective monobromination of activated aromatic compounds using NBS in combination with ionic liquid 1-butyl-1-methylimidazolium bromide ([Bmim]Br) or dioxane. The ionic liquid is recyclable and can be reused with minimal loss in the catalytic efficiency if the ionic liquid is rapidly microwaved prior to reactions.
- Pingali, Subramanya R.K.,Madhav, Monika,Jursic, Branko S.
-
experimental part
p. 1383 - 1385
(2010/04/25)
-
- Efficient and regioselective bromination of aromatic compounds with ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB)
-
A regioselective and highly efficient method for bromination of phenol and aniline derivatives using ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB) as an efficient reagent in dichloromethane at ambient temperature is reported. The reagent can be recovered and reused several times.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Mohadjerani, Maryam,Lasemi, Zahra
-
experimental part
p. 868 - 876
(2010/05/18)
-
- Efficient synthesis of 5-nitro-benzo[b]furans via 2-bromo-4-nitro-phenyl acetates
-
Acetylation/Sonogashira cross-coupling reaction/cyclization has been carried out in one-pot using a Na2PdCl4/2-(di-tert-butylphosphino)-N-phenylindole/CuI system in TMEDA to give 5-nitro-2-substituted benzo[b]furans in excellent yields. We also describe the extension of this method to 4-EWG-2-bromo-phenols obtaining 2,5-disubstituted-benzo[b]furans in good yields.
- Bochicchio, Antonella,Chiummiento, Lucia,Funicello, Maria,Lopardo, Maria Teresa,Lupattelli, Paolo
-
experimental part
p. 2824 - 2827
(2010/07/04)
-
- An efficient, rapid, and regioselective bromination of anilines and phenols with 1-butyl-3-methylpyridinium tribromide as a new reagent/solvent under mild conditions
-
1-Butyl-3-methylpyridinium tribromide, [BMPy]Br3 proves to be a highly efficient, regioselective reagent/solvent for nuclear bromination of various anilines and phenols. The synthesis and characterization of the room temperature ionic liquid [BMPy]Br3 (2) is described. The bromination was carried out in the absence of organic solvents and in most cases the only extraction solvent needed was water. The spent 1-butyl-3-methylpyridinium bromide (1) was easily recycled.
- Borikar, Sanjay P.,Daniel, Thomas,Paul, Vincent
-
scheme or table
p. 1007 - 1009
(2009/05/11)
-
- Environmentally benign electrophilic and radical bromination 'on water': H2O2-HBr system versus N-bromosuccinimide
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A H2O2-HBr system and N-bromosuccinimide in an aqueous medium were used as a 'green' approach to electrophilic and radical bromination. Several activated and less activated aromatic molecules, phenylsubstituted ketones and styrene were efficiently brominated 'on water' using both systems at ambient temperature and without an added metal or acid catalyst, whereas various non-activated toluenes were functionalized at the benzyl position in the presence of visible light as a radical activator. A comparison of reactivity and selectivity of both brominating systems reveals the H2O2-HBr system to be more reactive than NBS for benzyl bromination and for the bromination of ketones, while for electrophilic aromatic substitution of methoxy-substituted tetralone it was higher for NBS. Also, higher yields of brominated aromatics were observed when using H2O2-HBr 'on water'. Bromination of styrene reveals that not just the structure of the brominating reagent but the reaction conditions: amount of water, organic solvent, stirring rate and interface structure, play a key role in defining the outcome of bromination (dibromination vs bromohydroxylation). In addition, mild reaction conditions, a straightforward isolation procedure, inexpensive reagents and a lower environment impact make aqueous brominating methods a possible alternative to other reported brominating protocols.
- Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
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experimental part
p. 4429 - 4439
(2009/10/09)
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- Adamantyl-substituted retinoid-derived molecules that interact with the orphan nuclear receptor small heterodimer partner: Effects of replacing the 1-adamantyl or hydroxyl group on inhibition of cancer cell growth, induction of cancer cell apoptosis, and inhibition of Src homology 2 domain-containing protein tyrosine phosphatase-2 activity
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(E)-4-[3-(1-Adamantyl)-4′-hydroxyphenyl]-3-chlorocinnamic acid (3-Cl-AHPC) induces the cell-cycle arrest and apoptosis of leukemia and cancer cells. Studies demonstrated that 3-Cl-AHPC bound to the atypical orphan nuclear receptor small heterodimer partner (SHP). Although missing a DNA-binding domain, SHP heterodimerizes with the ligand-binding domains of other nuclear receptors to repress their abilities to induce or inhibit gene expression. 3-Cl-AHPC analogues having the 1-adamantyl and phenolic hydroxyl pharmacophoric elements replaced with isosteric groups were designed, synthesized, and evaluated for their inhibition of proliferation and induction of human cancer cell apoptosis. Structure-anticancer activity relationship studies indicated the importance of both groups to apoptotic activity. Docking of 3-Cl-AHPC and its analogues to an SHP computational model that was based on the crystal structure of ultraspiracle complexed with 1-stearoyl-2-palmitoylglycero-3-phosphoethanolamine suggested why these 3-Cl-AHPC groups could influence SHP activity. Inhibitory activity against Src homology 2 domain-containing protein tyrosine phosphatase 2 (Shp-2) was also assessed. The most active Shp-2 inhibitor was found to be the 3′-(3,3-dimethylbutynyl) analogue of 3-Cl-AHPC.
- Dawson, Marcia I.,Xia, Zebin,Jiang, Tao,Ye, Mao,Fontana, Joseph A.,Farhana, Lulu,Patel, Bhaumik,Li, Ping Xue,Bhuiyan, Mohammad,Pellicciari, Roberto,Macchiarulo, Antonio,Nuti, Roberto,Zhang, Xiao-Kun,Han, Young-Hoon,Tautz, Lutz,Hobbs, Peter D.,Jong, Ling,Waleh, Nahid,Chao, Wan-Ru,Feng, Gen-Sheng,Pang, Yuhong,Su, Ying
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supporting information; experimental part
p. 5650 - 5662
(2009/08/09)
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- Regioselective, photochemical bromination of aromatic compounds using N-bromosuccinimide
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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.
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p. 189 - 194
(2008/03/30)
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- The element effect and nucleophilicity in nucleophilic aromatic photosubstitution (SNAR*). Local atom effects as mechanistic probes of very fast reactions
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(Chemical Equation Presented) Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen = F, Cl, Br, and I) with the nucleophiles hydroxide ion and pyridine have been investigated quantitatively to extend the findings recently communicated for cyanide ion. The halonitroanisoles on excitation form triplet π,π* states, which undergo substitution of the halogen by nucleophiles. Chemical yields of photoproducts, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields are reported for the five compounds with the three nucleophiles. Following a standard kinetic treatment, 73 rate constants are determined for elementary reactions of the triplets including quenching and various nucleophilic addition processes. The photoadditions are roughly 14 orders of magnitude faster than thermal counterparts. Rate constants for attack at the fluorine-bearing carbon of triplet 2-fluoro-4-nitroanisole are 2.9 × 109, 1.3 × 109, and 6.3 × 108 M-1 s-1 for cyanide ion, hydroxide ion, and pyridine, respectively. The relative rates for attack at the halogen-bearing carbons for F/Cl/Br/I are 27:1.9:1.9:1 (cyanide ion), 29:2.6:2.4:1 (hydroxide ion), and 39:3.9: 3.5:1 (pyridine), respectively. The relative nucleophilicities vary somewhat with the attack site; they are about 5:2:1 for cyanide ion, hydroxide ion, and pyridine for attack at the halogen-bearing carbons. The trend of the element effect opposes that of aliphatic substitution and elimination but is similar in size and parallel to that of thermal nucleophilic aromatic substitution. Relative nucleophilicities in the photoreactions are also similar to those of comparable but vastly slower thermal reactions. The findings imply that the efficiency-determining step of the halogen photosubstitution is simple formation of a σ-complex through electron-paired bonding within the triplet manifold.
- Wubbels, Gene G.,Brown, Toby R.,Babcock, Travis A.,Johnson, Kandra M.
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p. 1925 - 1934
(2008/09/19)
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- Bromination of some aromatic compounds with potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate
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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
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p. 323 - 328
(2007/10/03)
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- A convenient and regioselective oxidative bromination of electron-rich aromatic rings using potassium bromide and benzyltriphenylphosphonium peroxymonosulfate under nearly neutral reaction conditions
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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
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p. 1255 - 1259
(2007/10/03)
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- Nitration of substituted phenols by different efficient heterogeneous systems
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Nitration of substituted phenols were carried out by the mixture of sodium nitrite and wet SiO2 (50% w/w) in the presence of four different efficient heterogeneous systems: 1) oxalic acid dihydrate (I), 2) sodium hydrogen sulphate (II), 3) aluminum hydrogen sulphate (III) and 4) silica sulphuric acid (IV) in CH2Cl2 at room temperature and high yields. Optimum conditions for theses systems and the regioselectivities of the reactions are reported.
- Habibi, Davood,Zolfigol, Mohammad Ali,Shiri, Morteza,Sedaghat, Abdolmajid
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- Anilinoquinazolines as protein tyrosine kinase inhibitors
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Heteroaromatic compounds are described, methods for their preparation, pharmaceutical compositions containing them, methods of use, and their use in medicines. In particular, the invention relates to quinazoline and pyridopyrimidine derivatives which exhibit protein tyrosine kinase inhibition.
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Page/Page column 74
(2008/06/13)
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- Anilinoquinazaolines as protein tyrosine kianse inhibitors
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Heteroaromatic compounds are described, methods for their preparation, pharmaceutical compositions containing them, methods of use, and their use in medicines. In particular, the invention relates to quinazoline and pyridopyrimidine derivatives which exhibit protein tyrosine kinase inhibition.
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Page/Page column 46
(2008/06/13)
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- CANCER TREATMENT METHOD
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A method of treating cancer is described including administration of a pyrimidine derivative and a quinazoline derivative as well as a pharmaceutical composition including the same.
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Page/Page column 48
(2010/02/14)
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- Nitration of phenolic compounds by metal-modified montmorillonite KSF
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The nitration of phenolic compounds with 60% nitric acid (1.2 equiv) has been carried out in the presence of metal-modified montmorillonite KSF, prepared from different metals (V, Mo, W; Sc, La, Yb, Eu, In, Bi, Ti, Zr, Hf) and KSF or nitric acid treated HKSF, as catalysts. These catalysts showed good stabilities and high catalytic activities in nitration process. In addition, these catalysts can be recovered easily and reused for many times in nitration. This process is an eco-safer and environment-benign way for clean synthesis of nitrated phenolic compounds.
- Yin, Wan-Po,Shi, Min
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p. 10861 - 10867
(2007/10/03)
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- An intriguing effect of lithium perchlorate dispersed on silica gel in the bromination of aromatic compounds by N-bromosuccinimide
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A convenient and efficient procedure for electrophilic aromatic bromination has been developed by mixing of N-bromosuccinimide and an aromatic compound at room temperature on the surface of silica gel mixed with solid anhydrous LiClO4. All of the substrates examined underwent clean electrophilic aromatic bromination in reaction times of a few minutes to afford the corresponding bromoarenes under neutral conditions in excellent yield. In the case of thiophenol, no substitution reaction occurred, and the corresponding disulfide was obtained in excellent yield.
- Bagheri, Mojtaba,Azizi, Najmedin,Saidi, Mohammad R.
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p. 146 - 149
(2007/10/03)
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- Kinetics and mechanism of bromination of phenols by sodium bromate-sodium bisulphite reagent in water-acetonitrile mixture
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Kinetics of bromination of phenols with HOBr produced in situ from sodium bromate-sodium bisulphite reagent has been studied in water-acetonitrile mixture iodometrically. The order of the reaction is found to be unity in [HOBr] and fractional in [phenol]. HOBr has been established as the effective brominating species. A mechanism involving a six-membered cyclic adduct between phenol and HOBr, which decomposes in a slow step has been proposed. Thermodynamic parameters for the formation of adduct and the activation parameters for the first order decomposition of the adduct have been evaluated and discussed. The influence of the substituents on the first order decomposition rate constant (k/s-1) of the adduct has been discussed. The sole reaction product has been identified as the corresponding o-bromophenol.
- Viroopakshappa,Jagannadham
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p. 532 - 534
(2007/10/03)
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- Cancer treatment method
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A method of treating cancer is described including administration of a 4-quinazolineamine and at least one other anti-neoplastic agent as well as a pharmaceutical combination including the 4-quinazolineamines.
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- Selective nitration of aromatic compounds with bismuth subnitrate and thionyl chloride
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Bismuth subnitrate/thionyl chloride have been found to be an efficient combination of reagents for nitration of a wide range of aromatic compounds in dichloromethane. Phenols, in particular, were easily mononitrated and dinitrated with the reagents by controlling the stoichiometry.
- Muathen, Hussni A.
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p. 593 - 598
(2007/10/03)
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