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Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
p. 9561 - 9568
(2021/08/06)

Selective Mild Oxidation of Anilines into Nitroarenes by Catalytic Activation of Mesoporous Frameworks Linked with Gold-Loaded Mn3O4 Nanoparticles
This work reports the synthesis and catalytic application of mesoporous Au-loaded Mn3O4 nanoparticle assemblies (MNAs) with different Au contents, i. e., 0.2, 0.5 and 1 wt %, towards the selective oxidation of anilines into the corresponding nitroarenes. Among common oxidants, as well as several supported gold nanoparticle platforms, Au/Mn3O4 MNAs containing 0.5 wt % Au with an average particle size of 3–4 nm show the best catalytic performance in the presence of tert-butyl hydroperoxide (TBHP) as a mild oxidant. In all cases, the corresponding nitroarenes were isolated in high to excellent yields (85–97 %) and selectivity (>98 %) from acetonitrile or greener solvents, such as ethyl acetate, after simple flash chromatography purification. The 0.5 % Au/Mn3O4 catalyst can be isolated and reused four times without a significant loss of its activity and can be applied successfully to a lab-scale reaction of p-toluidine (1 mmol) leading to the p-nitrotulene in 83 % yield. The presence of AuNPs on the Mn3O4 surface enhances the catalytic activity for the formation of the desired nitroarene. A reasonable mechanism was proposed including the plausible formation of two intermediates, the corresponding N-aryl hydroxylamine and the nitrosoarene.
Armatas, Gerasimos S.,Daikopoulou, Vassiliki,Koutsouroubi, Eirini D.,Lykakis, Ioannis N.,Skliri, Euaggelia
(2021/11/01)

Low-temperature and highly efficient liquid-phase catalytic nitration of chlorobenzene with NO2: Remarkably improving the para-selectivity in O2-Ac2O-Hβ composite system
In this work, we developed a low-temperature and efficient approach for the highly selective preparation of valuable p-nitrochlorobenzene from the liquid-phase catalytic nitration of chlorobenzene with NO2 in O2-Ac2O-Hβ composite system. The results demonstrated that the introduction of molecular oxygen remarkably enhanced the chlorobenzene conversion and the cooperation catalysis of Hβ zeolite and Ac2O envidently improved the selectivity to para-nitro product. Under the optimized reaction conditions, 93.6 % of the selectivity to p-nitrochlorobenzene with 84.0 % of chlorobenzene conversion was obtained, and the ratio of p-nitrochlorobenzene to o-nitrochlorobenzene could reach up to 20.3. Furthermore, the selectivity distribution of nitration products was reasonably explained by the density functional theory (DFT) calculation. Finally, the possible nitration reaction pathway of chlorobenzene with NO2 was suggested in O2-Ac2O-Hβ composite catalytic system. The present work affords a new and mild nitration approach for highly selective preparation of valuable para-nitro products, and has potential industrial application prospects.
Deng, Renjie,Liu, Pingle,Luo, He'an,Ni, Wenjin,You, Kuiyi,Zhao, Fangfang
(2020/02/26)

Direct Stereoselective β-Arylation of Enol Ethers by a Decarboxylative Heck-Type Reaction
Despite remarkable advances to promote regio- and stereoselective decarboxylative arylation of inactivated olefins with benzoic acid derivatives, methodologies involving hetero-substituted alkenes are still lacking. Herein, PdII-catalyzed decarboxylative Heck coupling of α-alkoxyacrylates with (hetero)aryl carboxylic acids for the stereocontrolled production of (Z)-β-heteroarylated vinyl ethers is reported. This methodology offers a rational and step-economical route to the synthesis of attractive β-arylated α-alkoxy α,β-unsaturated carboxylates family which emerged as a relevant class of building blocks with different applications. Mechanistically, whereas electron rich benzoic acids undergo a PdII-catalyzed decarboxylation, electron-deficient substrates proceed through silver(I)-mediated decarboxylation, explaining thus the formation of stereoisomers (E) and (Z) of β-arylated vinyl ethers in presence of these latter.
Hachem, Mahmoud,Hoarau, Christophe,Schneider, Cédric
(2020/04/15)

Preparation method 3- methoxyl diphenylamine (by machine translation)
3 -methoxydiphenylamine, is obtained, by adding PEG - 800,methoxybenzonitrobenzene 140 °C to a high-pressure reaction kettle, and heating to 2h, after heating to, and heating the methanol, to react, with methanol to obtain, metoonitrobenzene. 3 - reaction liquid distilled dry solvent; is added to the high-pressure reaction kettle. 3 - and then reacted at room temperature, and stirred for, hours under reduced pressure . reaction solution is evaporated and distilled off under reduced pressure 90 °C, by a reaction solution distilled 10h from, a reaction, solution distilled, from a reaction, solution distilled from, a 3 - reaction solution evaporated; in a reaction solution of, a reaction, liquid distilled from, a reaction solution of a, reaction liquid distilled from a reaction, solution distilled from a reaction solution distilled from a reaction solution of a reaction solution. (by machine translation)
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(2020/04/17)

Base promoted peroxide systems for the efficient synthesis of nitroarenes and benzamides
A useful and efficient approach for the synthesis of nitroarenes from several aromatic amines (including heterocycles) using peroxide and base has been developed. This oxidative reaction is very easy to handle and afforded the products in good yields. Formation of benzamides from benzylamine was also successfully carried out with this metal-free catalytic system in good to excellent yields.
Gupta, Sampa,Ansari, Alisha,Sashidhara, Koneni V.
supporting information

(2019/09/07)

Dimethyl sulfoxide-accelerated reductive deamination of aromatic amines with t-BuONO in tetrahydrofuran
An efficient method for the conversion of aryl amines into arenes by a one-pot reductive deamination has been achieved. It was found the reductive deamination using t-BuONO in tetrahydrofuran could be accelerated by dimethyl sulfoxide and provided the deamination products with good yields under mild conditions. A plausible mechanism is discussed.
Fang, Lu,Qi, Liang,Ye, Longfei,Pan, Zhentao,Luo, Wenjun,Ling, Fei,Zhong, Weihui
p. 579 - 583
(2018/11/27)

Study on the degradation mechanism and pathway of benzene dye intermediate 4-methoxy-2-nitroaniline: Via multiple methods in Fenton oxidation process
Benzene dye intermediate (BDI) 4-methoxy-2-nitroaniline (4M2NA) wastewater has caused significant environmental concern due to its strong toxicity and potential carcinogenic effects. Reports concerning the degradation of 4M2NA by advanced oxidation process are limited. In this study, 4M2NA degradation by Fenton oxidation has been studied to obtain more insights into the reaction mechanism involved in the oxidation of 4M2NA. Results showed that when the 4M2NA (100 mg L-1) was completely decomposed, the TOC removal efficiency was only 30.70-31.54%, suggesting that some by-products highly recalcitrant to the Fenton oxidation were produced. UV-Vis spectra analysis based on Gauss peak fitting, HPLC analysis combined with two-dimensional correlation spectroscopy and GC-MS detection were carried out to clarify the degradation mechanism and pathway of 4M2NA. A total of nineteen reaction intermediates were identified and two possible degradation pathways were illustrated. Theoretical TOC calculated based on the concentration of oxalic acid, acetic acid, formic acid, and 4M2NA in the degradation process was nearly 94.41-97.11% of the measured TOC, indicating that the oxalic acid, acetic acid and formic acid were the main products. Finally, the predominant degradation pathway was proposed. These results could provide significant information to better understand the degradation mechanism of 4M2NA.
Guo, Ying,Xue, Qiang,Cui, Kangping,Zhang, Jia,Wang, Hui,Zhang, Huanzhen,Yuan, Fang,Chen, Honghan
p. 10764 - 10775
(2018/03/26)

A Predictive Model for the Decarboxylation of Silver Benzoate Complexes Relevant to Decarboxylative Coupling Reactions
Decarboxylative coupling reactions offer an attractive route to generate functionalized arenes from simple and readily available carboxylic acid coupling partners, yet they are underutilized due to limitations in the scope of carboxylic acid coupling partner. Here we report that the field effect parameter (F) has a substantial influence on the rate of decarboxylation of well-defined silver benzoate complexes. This finding provides the opportunity to surpass current substrate limitations associated with decarboxylation and to enable widespread utilization of decarboxylative coupling reactions.
Crovak, Robert A.,Hoover, Jessica M.
p. 2434 - 2437
(2018/02/28)

NH4I/tert-butyl hydroperoxide-promoted oxidative C–N cleavage of tertiary amines leading to nitroaromatic compounds
A NH4I/tert-butyl hydroperoxide-promoted oxidation of tertiary N-aryl-N,N-dialkylamines in DMSO has been developed to access nitroaromatic compounds. This methodology involves sequential N-dealkylation reactions in one-pot and a radical pathway is proposed.
Shao, Ying,Zheng, Hao,Wu, Zhuhong,Huang, Lei,Tong, Jingjing,Wu, Ming,Sun, Xiaoqiang
p. 504 - 508
(2017/10/03)

Salicylic Acid-Catalyzed One-Pot Hydrodeamination of Aromatic Amines by tert-Butyl Nitrite in Tetrahydrofuran
A significant acceleration in the hydrodeamination of in situ formed diazonium salts (from aromatic amines) has been observed in the presence of 10-mol% salicylic acid, using tetrahydrofuran as the hydrogen donor. The reaction proceeds efficiently at 20 °C for a wide range of substituted anilines, even at 10-mmol scale, without any other additive. The same protocol has been adapted to the selective deuterodeamination of some aromatic amines. Control experiments clearly show that aryl radicals are involved in the reaction mechanism. (Figure presented.).
Felipe-Blanco, Diego,Alonso, Francisco,Gonzalez-Gomez, Jose C.
p. 2857 - 2863
(2017/08/23)

Organocatalytic oxidation of substituted anilines to azoxybenzenes and nitro compounds: Mechanistic studies excluding the involvement of a dioxirane intermediate
An organocatalytic and environmentally friendly approach for the selective oxidation of substituted anilines was developed. Utilizing a 2,2,2-trifluoroacetophenone-mediated oxidation process, substituted anilines can be transformed into azoxybenzenes, while a simple treatment with MeCN and H2O2 leads to the corresponding nitro compounds, providing user-friendly protocols that can be easily scaled up. Various substitution patterns and functional groups were tolerated leading to products in high to excellent yields. Mechanistic studies utilizing HRMS provide clear evidence for the distinct mechanistic intermediates that are involved. This study constitutes an indirect proof excluding the involvement of a dioxirane intermediate in the green organocatalytic oxidation, utilizing 2,2,2-trifluoroacetophenone as the catalyst.
Voutyritsa, Errika,Theodorou, Alexis,Kokotou, Maroula G.,Kokotos, Christoforos G.
supporting information
p. 1291 - 1298
(2017/06/06)

Acid-catalysed carboxymethylation, methylation and dehydration of alcohols and phenols with dimethyl carbonate under mild conditions
Dimethyl carbonate (DMC) chemistry has been extended to include acid-catalysed reactions of different aliphatic alcohols and phenols. For the first time, p-toluenesulfonic acid (PTSA), H2SO4, AlCl3 and FeCl3 have been shown to aid carboxymethylation for primary aliphatic alcohols at catalytic loadings with quantitative conversion and selectivity. For carboxymethylation of secondary alcohols, stoichiometric PTSA and catalytic AlCl3 both gave quantitative conversion and selectivity. Stoichiometric FeCl3 and H2SO4 promoted dehydration of linear aliphatic alcohols. Additionally FeCl3 catalysed methylation of cyclohexanol, whilst AlCl3 resulted in methylation of phenolic compounds. This research expands the range of potential application for DMC in green chemistry.
Jin, Saimeng,Hunt, Andrew J.,Clark, James H.,McElroy, Con Robert
supporting information
p. 5839 - 5844
(2016/11/06)

A simple protocol for Cu-catalyzed protodecarboxylation of (hetero)aromatic carboxylic acids
A simple and practical protodecarboxylation of o-nitrobenzoic acids as well as heteroaromatic carboxylic acids with various substituents via using CuI/Et3N has been established. This transformation provides a viable and low-cost approach to generating previously unavailable substituted arenes from readily accessible aryl carboxylic acids as the starting materials.
Li, Zhaojie,Fu, Zhengjiang,Zhang, Haixia,Long, Jiao,Song, Yuanyuan,Cai, Hu
supporting information
p. 3014 - 3018
(2016/05/09)

Controlling the Course of a Two-Way Switchable Pd-Catalyzed Process by means of Empirical Multivariate Models
A two-way switchable Pd-catalyzed process that can pursue two different mechanisms, namely hydro- and methoxy-deiodination was discovered, developed, and optimized by means of statistical experimental design, multivariate modelling, and response surface methodology. The investigation revealed that the two-way switchable process might be controlled either by ligand alone, or by ligand and other process variables in combination. The present study represents the first example of a catalytic system that provides either hydro- or methoxy-deiodination selectively by simply fine-tuning the experimental variables.
Sandtorv, Alexander H.,Bj?rsvik, Hans-René
p. 2196 - 2205
(2015/11/24)

Steric-Hindrance-Induced Regio- and Chemoselective Oxidation of Aromatic Amines
Unusual regio- and chemoselective oxidation of aromatic amines hindered with ortho substituents (except -NH2, -NHCH3, and -OH) to the corresponding nitro compounds is described by use of nonanebis(peroxoic acid). The mechanistic investigation for selective oxidation of amines ortho-substituted with -NH2 or -OH showed the involvement of H-bonding between the ortho hydrogen of the adjacent -XH group (where X = NH, NR, or O) and an oxygen atom from the diperoxy acid. Various mono- and diamines are oxidized into corresponding mononitro derivatives in high yield and purity without employing any protection strategies. The protocol was also found to successful on the gram scale.
Patil, Vilas Venunath,Shankarling, Ganapati Subray
p. 7876 - 7883
(2015/09/01)

Trifluoromethylation of arenediazonium salts with fluoroform-derived CuCF3 in aqueous media
A new protocol has been developed for trifluoromethylation of arenediazonium salts with moisture-sensitive CuCF3 (from fluoroform) in aqueous media. The reaction is governed by a radical mechanism, tolerates a broad variety of functional groups, and is applicable to the synthesis of complex, polyfunctionalized molecules. This journal is the Partner Organisations 2014.
Lishchynskyi, Anton,Berthon, Guillaume,Grushin, Vladimir V.
supporting information
p. 10237 - 10240
(2014/08/18)

Click chemistry inspired facile synthesis and bioevaluation of novel triazolyl analogs of Ludartin
A convenient and modular synthesis involving diastereoselective Michael addition followed by regioselective Huisgen 1,3-dipolar cycloaddition reaction was carried out to furnish 1,4-disubstituted-1,2,3-triazoles of Ludartin. This reaction scheme involving Michael addition followed by regioselective Huisgen 1,3-dipolar cycloaddition reaction leading to the formation of triazolyl analogs is being reported for the first time. All the triazolyl products were characterised using spectral data analysis. Sulphorhodamine B cytotoxicity screening of the resulting products against a panel of five human cancerous cell-lines revealed that few of the analogs display promising broad spectrum cytotoxic effect. Among all the synthesized compounds, only 3q displayed the best cytotoxic effect with IC50 values of 12, 11, 38, 39 and 8.5 μM but less than the standard Ludartin (1) with IC50 values of 6.3, 7.4, 7.5, 6.9 and 0.5 μM against human neuroblastoma (T98G), lung (A-549), prostate (PC-3), colon (HCT-116) and breast (MCF-7) cancer cell lines, respectively. The present synthesis was designed based on the previous literature reports of Ludartin as an aromatase inhibitor. Our work provides an initial study on structure-activity relationship of triazolyl analogs of sesquiterpene lactones in general and Ludartin (1) in particular.
Lone, Shabir H.,Bhat, Khursheed A.,Majeed, Rabiya,Hamid, Abid,Khuroo, Mohd A.
p. 1047 - 1051
(2014/03/21)

Copper MOF: Scope and limitation in catalytic hydroxylation and nitration of aryl halides
The potential catalytic application of MOFs like [Cu3(btc) 2] (btc=1,3,5-benzenetricarboxylate), [Cu(bdc)] (bdc=1,4- benzenedicarboxylate), [Cu(pymo)2] (pymo=2-hydroxypyrimidinalote) and [Cu(im)2] (im=imidazolate) was explored in the hydroxylation and nitration of aryl halides. Cu3(btc)2 was found to be superior for both the reactions furnishing good to excellent yields of the respective products. The studies demonstrated that MOFs are not recyclable, attributable to their instability in the highly polar and basic conditions demanded for these reactions. Complete transformation of MOFs to copper oxide nanoparticles occurred in hydroxylation, whereas significant alteration in frameworks was observed for the recovered catalyst in nitration.
Priyadarshini,Amal Joseph,Kantam, M. Lakshmi,Sreedhar
p. 6409 - 6414
(2013/07/26)

Amino acid intercalated layered double hydroxide catalyzed chemoselective methylation of phenols and thiophenols with dimethyl carbonate
Sixteen different amino acids are intercalated into Mg-Al layered double hydroxides (LDHs) by the reconstruction method and are characterized by powder XRD and FT-IR. The intercalated amino acid-LDHs (AA-LDHs) are used as catalysts for chemoselective O-methylation of phenol and S-methylation of thiophenol with dimethyl carbonate (DMC) as a green methylating agent. The intercalation behavior of various amino acids is influenced by various structural features of amino acids, namely, carbon chain length, structure, and physicochemical properties. In particular, amino acids possessing a hydrophobic side-chain show higher catalytic activity. A suitable reaction mechanism is proposed. The catalyst can also be recycled.
Subramanian, Thirumeni,Dhakshinamoorthy, Amarajothi,Pitchumani, Kasi
p. 7167 - 7170
(2013/12/04)

Efficient ipso-nitration of arylboronic acids with iron nitrate as the nitro source
A novel, simple and efficient ipso-nitration of arylboronic acids with iron nitrate has been developed. The protocol uses readily available arylboronic acids as the starting materials, inexpensive iron nitrate (0.5 equiv.) as the nitro source without addition of an additive, and the corresponding nitroarenes were obtained in good to excellent yields.
Jiang, Min,Yang, Haijun,Li, Yong,Jia, Zhiying,Fu, Hua
p. 25602 - 25604
(2013/12/04)

Dissecting metabolic puzzles through isotope feeding: A novel amino acid in the biosynthetic pathway of the cruciferous phytoalexins rapalexin A and isocyalexin A
Understanding defence pathways of plants is crucial to develop disease-resistant agronomic crops, an important element of sustainable agriculture. For this reason, natural plant defenses such as phytoalexins, involved in protecting plants against microbial pathogens, have enormous biotechnological appeal. Crucifers are economically important plants, with worldwide impact as oilseeds, vegetables of great dietetic value and even nutraceuticals. Notably, the intermediates involved in the biosynthetic pathways of unique cruciferous phytoalexins such as rapalexin A and isocyalexin A remain unknown. Toward this end, using numerous perdeuterated compounds, we have established the potential precursors of these unique phytoalexins and propose for the first time their detailed biosynthetic pathway. This pathway involves a variety of intermediates and a novel amino acid as the central piece of this complex puzzle. This work has set the stage for the discovery of enzymes and genes of the biosynthetic pathway of cruciferous phytoalexins of unique scaffolds.
Pedras, M. Soledade C.,Yaya, Estifanos E.
p. 1149 - 1166
(2013/03/29)

Copper catalyzed ipso-nitration of iodoarenes, bromoarenes and heterocyclic haloarenes under ligand-free conditions
A catalytic protocol for the conversion of haloarenes into the corresponding nitroarenes is presented using copper salts under ligand-free conditions. The method was effectively utilized for the ipso-nitration of a broad variety of haloarenes that includes iodoarenes, bromoarenes, and heterocyclic haloarenes.
Amal Joseph,Priyadarshini,Lakshmi Kantam,Maheswaran
supporting information; experimental part
p. 1511 - 1513
(2012/03/27)

Rapid microwave-assisted copper-catalyzed nitration of aromatic halides with nitrite salts
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Paik, Seunguk,Jung, Myoung Geun
experimental part
p. 689 - 691
(2012/04/23)

Green and controllable metal-free nitrification and nitration of arylboronic acids
A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to the traditional nitration protocols.
Wang, Shuai,Shu, Chun Chun,Wang, Tao,Yu, Jian,Yan, Guo Bing
scheme or table
p. 643 - 646
(2012/08/07)

Protodecarboxylation of benzoic acids under radical conditions
A new approach to protodecarboxylation is described that enhances the substrate scope for benzoic acids. The reaction uses oxidative radical conditions to decarboxylate a variety of acids in acetonitrile.
Seo, Sangwon,Taylor, John B.,Greaney, Michael F.
supporting information; experimental part
p. 8270 - 8272
(2012/09/07)

General copper-catalyzed transformations of functional groups from arylboronic acids in water
A simple and general copper-catalyzed method has been developed for transformations of various functional groups (i I, i N3, i SO2R, i OH, i NH2, and i NO 2) on aromatic rings from arylboronic acids in water under air. The protocol uses cheap and readily available inorganic salts (KI, NaN3, NaSO2R, NaOH, NaNO2) and aqueous ammonia as the functional-group sources, simple Cu2O/NH3 as the catalyst system, environmentally friendly water as the solvent, and oxygen in air as the oxidant. Importantly, the copper catalyst system in water was recyclable. This study should provide a useful strategy for interconversions of the functional groups on aromatic rings.
Yang, Haijun,Li, Yong,Jiang, Min,Wang, Junmei,Fu, Hua
experimental part
p. 5652 - 5660
(2011/06/23)

Diclofenac derivatives with insulin-sensitizing activity
A series of diclofenac derivatives were synthesized. The insulin-sensitizing activity of 28 new compounds was evaluated in 3T3-L1 cells. The compounds 10a and 10f exhibited similar insulin-sensitizing activity with positive drug rosiglitazone.
Wang, Jian Ta,Wang, Ying,Zhang, Ji Quan,Cui, Xing,Zhang, Yi,Zhu, Gao Feng,Tang, Lei
scheme or table
p. 409 - 412
(2012/01/06)

Microwave-accelerated fluorodenitrations and nitrodehalogenations: expeditious routes to labeled PET ligands and fluoropharmaceuticals
Methods for the expeditious fluorination of arenes have been investigated, using readily available fluoride sources. An optimized procedure for microwave-accelerated fluorodenitration has been developed, giving good to excellent yields in less than 10 min, rendering it practical for use in the preparation of F18 labeled ligands for PET imaging. Application of the method in the synthesis of CNS agents is demonstrated, and a practical method for the preparation of substrates is also presented.
LaBeaume, Paul,Placzek, Michael,Daniels, Mathew,Kendrick, Ian,Ng, Patrick,McNeel, Melissa,Afroze, Roushan,Alexander, Abigail,Thomas, Rhiannon,Kallmerten, Amy E.,Jones, Graham B.
experimental part
p. 1906 - 1909
(2010/09/07)

Decarboxylative homocoupling of (hetero)aromatic carboxylic acids
A variety of hetero(aromatic) carboxylic acids are shown to undergo decarboxylative homocoupling, mediated by a Pd/Ag system. This novel methodology for the synthesis of symmetrical biaryls avoids the use of haloarenes and organometallic compounds as starting materials.
Cornella, Josep,Lahlali, Hicham,Larrosa, Igor
supporting information; experimental part
p. 8276 - 8278
(2010/12/19)

Silver-catalysed protodecarboxylation of ortho-substituted benzoic acids
Catalytic amounts of Ag(i) salts in DMSO have been found to promote the protodecarboxylation of a wide variety of ortho-substituted benzoic acids under mild conditions and in excellent yields, highlighting a possible role for silver in decarboxylative cross-couplings. The Royal Society of Chemistry 2009.
Cornella, Josep,Sanchez, Carolina,Banawa, David,Larrosa, Igor
supporting information; experimental part
p. 7176 - 7178
(2010/03/25)

Design, synthesis and insulin-sensitizing activity of indomethacin and diclofenac derivatives
A series of aromatic acetic acid compounds were designed and synthesized on the basis of Non-steroidal anti-inflammatory drugs indomethacin and diclofenac. Compounds 5a, 7a, 5h, 7h and 17 could strongly promote insulin-regulated differentiation of 3T3-L1 cells in vitro. They acted as full or partial PPARγ agonist, or improved insulin resistance through non-PPARγ pathway.
Zhang, Jiquan,Wang, Jianta,Wu, Haoshu,He, Yaoyao,Zhu, Gaofeng,Cui, Xing,Tang, Lei
scheme or table
p. 3324 - 3327
(2010/03/31)

Nitration of simple aromatics with NO2 under air atmosphere in the presence of novel Bronsted acidic ionic liquids
Aromatics nitrate with NO2/air catalyzed by novel Bronsted acidic ionic liquids (ILs) without any volatile chlorinated organic solvent under mild conditions. The ILs employed were caprolactam based, [Caprolactam]X (X-=pTSO-, BSO-, BF4-, NO3-), which are o
Qi, Xiufang,Cheng, Guangbin,Lu, Chunxu,Qian, Desheng
p. 537 - 545
(2008/04/12)

An efficient intermolecular BINAM-copper(I) catalyzed Ullmann-type coupling of aryl iodides/bromides with aliphatic alcohols
A wide range of alkyl aryl ethers are synthesized from the corresponding aryl iodides and aliphatic alcohols through Ullmann-type intermolecular coupling reactions in the presence of a catalytic amount of easily available BINAM-CuI complex. Less reactive aryl bromides have also been shown to react with aliphatic alcohols under identical reaction conditions to give good yields of the alkyl aryl ethers without increasing the reaction temperature and time.
Naidu, Ajay B.,Sekar
p. 3147 - 3151
(2008/09/20)

Thermodynamic study of σH complexes in nucleophilic aromatic substitution reactions: Relative stabilities of electrochemically generated radicals
The mechanism for the electrochemical oxidation of σH complexes, such as 1-hydro-1-alkoxy/sulfoxy or -fluoro-2,4-dinitro/2,4,6- trinitrocyclohexadienyl anions, has been widely studied by means of cyclic voltammetry and controlled-potential electrolysis. Previous studies have shown that the electrochemical oxidation of σH complexes, formed by the addition of carbon or nitrogen nucleophiles followed by a two electron mechanism, corresponding to the formal elimination of the hydride anion (nucleophilic aromatic substitution of hydrogen mechanism, the NASH mechanism). For these σH complexes (Nu- = OH-, -OR, -SR, -F), the electrochemical reaction takes place by a one-electron mechanism and is followed by the radical elimination of the leaving group with the consequent recovery of the starting material. This mechanism is similar to that proposed for the electrochemical oxidation of σX complexes (nucleophilic aromatic substitution of a heteroatom, the NASX mechanism). The operating mechanism in each case, the NASH or NASX, can be rationalized in terms of thermodynamics. The standard potentials of the σ complex and/or the leaving group as well as the bond dissociation energies (BDEs) are determinant factors. This study has not led to a significant improvement in the electrochemical preparation of aromatic-substituted compounds, but does help to understand and predict the usefulness or uselessness of using the nucleophilic aromatic substitution route to obtain a desired product. Finally, the current approach extends the electrochemical methodology to different chemical fields, for example, to general nondestructive methods for the detection, identification, and quantification of either organic pollutants or explosives in different solvents. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Gallardo, Iluminada,Guirado, Gonzalo
scheme or table
p. 2463 - 2472
(2009/04/06)

NOVEL COMPOUNDS AS AGONIST FOR PPAR GAMMA AND PPAR ALPHA, METHOD FOR PREPARATION OF THE SAME, AND PHARMACEUTICAL COMPOSITION CONTAINING THE SAME
The present invention relates to novel compounds accelerating the activity of Peroxisome proliferator-activated receptor gamma (PPARγ) and alpha (PPARα), processes of preparing the same, and pharmaceutical compositions containing the same as an active agent.
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Page/Page column 163

(2010/11/27)

Solvent-free Williamson synthesis: An efficient, simple, and convenient method for chemoselective etherification of phenols and bisphenols
Etherification of phenols with dimethyl- and diethylsulfates and benzyl chloride was performed efficiently in the presence of a suitable solid base, NaHCO3 or K2CO3, under solvent-free conditions. The reaction proceeded rapidly at low temperature, and the corresponding ethers were obtained with high purity and excellent yield. Selective etherification of electron-poor phenols in the presence of electron-rich ones and also selective mono-etherification of bisphenols are the noteworthy advantages of this method. This method is environmentally friendly. Copyright Taylor & Francis Group, LLC.
Massah, Ahmad R.,Mosharafian, Masumeh,Momeni, Ahamad R.,Aliyan, Hamid,Naghash, H. Javaherian,Adibnejad, Mohamad
p. 1807 - 1815
(2008/02/02)

Copper-catalyzed coupling of aryl halides and nitrite salts: A mild Ullmann-type synthesis of aromatic nitro compounds
Nitration of aromatic halides proceeded smoothly in the presence of catalytic amounts of Cu bronze and N,N′-dimethylethylenediamine. Sodium nitrite-18-crown-6, or tetra-n-butylammonium nitrite (n-Bu4NNO 2) turned out to be efficient nitrating agents. The aromatic nitro compounds were synthesized under essentially neutral conditions.
Saito, Shinichi,Koizumi, Yuichiro
p. 4715 - 4717
(2007/10/03)

Ethyl acetate as a pro-reducing agent in an one-pot reductive deamination of nitroanilines
The reductive deamination of various nitro-substituted anilines by the new method (20% H2SO4/NaNO2/ethyl acetate, Method 1) was studied and compared that with a similar procedure previously developed by Pare et al. (i.e., concentrated H2SO4/NaNO2/ethanol, Method 2) for the dediazonization of 4-methyl-2,6-dinitroaniline. The deaminated products derived from the mononitro-substituted anilines were obtained in good-to-high yield by Method 1 depending upon the position of the nitro group to the amino function. The higher yield of the de-aminated products was observed from the substituted meta-nitroanilines. Method 1 was more suitable for the deamination of 3-nitroanilines. Method 2 was more favorable for the de-amination of denitro-substituted anilines than that for the mononitroanilines. Ethyl acetate was more suitable for the reductive deamination of mononitroanilines, while ethanol was more appropriate for dinitroanilines.
Bacherikov, Valeriy A.,Wang, May-Jane,Cheng, Shu-Yun,Chen, Ching-Huang,Chen, Kuo-Tung,Su, Tsann-Long
p. 1027 - 1032
(2007/10/03)

One-step preparation of some 3-substituted anisoles
A one-step preparation of 3-bromoanisole, 3-chloroanisole, and 3-trifluoromethylanisole from the corresponding 3-substituted nitrobenzenes is carried out by nucleophilic aromatic substitution of the nitro group with sodium or potassium methoxide, employing an effective amount of a phase-transfer catalyst (PTC), in a medium of a nonpolar aprotic solvent, under aerobic conditions, at a temperature of 50-65°C. The alkali methoxide used can be a pre-prepared solid, or it can be prepared in situ from the alkali hydroxide and methanol. The methoxydenitration proved to be very sensitive to the type of PTC. The effect of the solvent on the reaction is discussed. The targeted anisoles are obtained in yields of more than 80% and purities of greater than 99%.
Zilberman, Joseph
p. 303 - 305
(2013/09/06)

Electrophilic tetraalkylammonium nitrate nitration. II. Improved anhydrous aromatic and heteroaromatic mononitration with tetramethylammonium nitrate and triflic anhydride, including selected microwave examples
A new one-pot nitration employing tetramethylammonium nitrate and trifluoromethanesulfonic anhydride in dichloromethane to provide a ready source of the nitronium triflate nitrating agent is presented. Rapid and selective nitration with a variety of aromatic and heteroaromatic substrates is achieved resulting in the synthesis of several novel organic compounds. A distinct advantage is the removal of undesired byproducts by aqueous workup. This very mild nitration permits large-scale syntheses and gives high isolated product yields that often require no further purification. This tetramethylammonium nitrate-based nitration also has been applied to microwave-assisted conditions, and the results with several compounds are outlined.
Shackelford, Scott A.,Anderson, Mark B.,Christie, Lance C.,Goetzen, Thomas,Guzman, Mark C.,Hananel, Martha A.,Kornreich, Wayne D.,Li, Haitao,Pathak, Ved P.,Rabinovich, Alex K.,Rajapakse, Ranjan J.,Truesdale, Larry K.,Tsank, Stella M.,Vazir, Haresh N.
p. 267 - 275
(2007/10/03)

The α-effect in methyl transfers from S-methyldibenzothiophenium fluoroborate to substituted N-methylbenzohydroxamates
Studies of the α-effect show increased reactivity of nucleophiles having lone pairs of electrons on atoms neighboring the lone pair involved in reactivity when compared to the basicity of the nucleophiles. Hammett-type plots and Broensted-type plots of substituted methylphenyl sulfates vs hydrogen peroxide anions and substituted N-methylbenzohydroxanates (NMBH) with substituted methylarenesulfonates or substituted arenedimethylsulfonium ions have large ρ or βnuc values, indicating a putative tightening of the usual SN2 transition states (anti-Hammond effect). Electrochemical studies of SN2-SET or reactivity indicate that SET character occurs in looser transition states, whereas SN2 transition states are associated with greater tightness. The α-effects for the series of sulfonium salts in completion reactions for 3-ClNMBH anions and 3-nitrophenolate anions are (log kα/knormal) 1.124 for dimethylphenyl sulfonium, 1.512 for dimethyl-1-naphthyl sulfonium, 1.835 for dimethyl-9-anthracenyl sulfonium, and 1.137 for S-methyldibenzylthiophenium. Correlations of the sizes of α-effects with typical SET (or ET) experimental parameters and the inverse dependence of the size of the α-effect on electron demand indicate inclusion of SET character in these SN2 transition states, vs no (or at least diminished) SET character in normal transition states. This dichotomy of tighter SN2 transition states, but looser SET transition states indicated in the α-effect, is examined in the present work.
Fountain,Felkerson, Cassie J.,Driskell, Jeremy D.,Lamp, Brian D.
p. 1810 - 1814
(2007/10/03)

Nucleophilic aromatic substitution for heteroatoms: An oxidative electrochemical approach
The nucleophilic aromatic substitution for heteroatom through electrochemical oxidation of the intermediate σ-complexes (Meisenheimer complexes) in simple nitroaromatic compounds is reported for the first time (NASX process). The studies have been carried out with hydride, cyanide, fluoride, methoxy, and ethanethiolate anions and n-butylamine as a nucleophile, at the cyclic voltammetry (CV) and preparative electrolysis level. The cyclic voltammetry experiments allow for detection and characterization of the σ-complexes and they have led us to a proposal for the mechanism of the oxidation step. Furthermore, the power of the CV technique in the analysis of the reaction mixture throughout the whole chemical and electrochemical process is described.
Gallardo, Iluminada,Guirado, Gonzalo,Marquet, Jordi
p. 2548 - 2555
(2007/10/03)

An efficient intermolecular palladium-catalyzed synthesis of aryl ethers [17]
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Torraca,Huang,Parrish,Buchwald
p. 10770 - 10771
(2007/10/03)

Direct methoxylation of nitroarenes and nitroazaarenes with alkaline methoxides via nucleophilic displacement of an aromatic hydrogen atom
Treatment of 1,3-dinitrobenzene and 5-substituted derivatives with excess potassium or sodium methoxide in 1,3-dimethylimidazolidin-2-one (DMI) at room temperature results in the displacement of an aromatic hydrogen at the 4-position by methoxide, affording 2,4-dinitroanisole and its 6-substituted derivatives, respectively, in low to moderate yield. In contrast, an equimolar reaction under similar conditions leads to the replacement of the nitro group in preference to the ring hydrogen. The reaction does not take place with lithium methoxide as a base. Mono- and dinitronaphthalenes and nitroquinolines undergo similar displacement of a hydrogen atom at the position ortho or para to the nitro group, giving the corresponding methoxy derivatives in moderate yield. A slow addition of the nitro compound to a large excess of potassium methoxide under an oxygen atmosphere has been found to enhance the conversion and improve the product yield. On the basis of the product distribution as well as the kinetic isotope effect kH/kD = 2.1, direct displacement of a ring hydrogen atom by methoxide ion has been interpreted in terms of the rate-determining release of an ipso-hydrogen atom as a proton from the initially formed Meisenheimer adduct.
Kawakami, Takehiko,Suzuki, Hitomi
p. 1259 - 1264
(2007/10/03)

Etherification of phenols catalysed by solid-liquid phase transfer catalyst PEG400 without solvent
Aromatic ethers were synthesised in excellent yields(above 86 %) and purity by the etherification of phenols with dimethyl sulfate or alkyl halides, catalysed by phase transfer catalyst PEG400 under solvent-free conditions, and the effects of some key reaction conditions were also studied.
Cao, Yu-Qing,Pei, Ben-Gao
p. 1759 - 1766
(2007/10/03)

Chemoselective O-methylation of phenols under non-aqueous condition
Chemoselective O-methylation of substituted phenols takes place in dry. tetrahydrofuran (THF) in the presence of LiOH.H2O and dimethylsulfate (DMS). Quantitative methyl transfer from DMS preserves the atom economy.
Basak, Anindita,Nayak, Mrinal K.,Chakraborti, Asit K.
p. 4883 - 4886
(2007/10/03)

Kinetics of the oxidation of aromatic C-nitroso compounds by nitrogen dioxide
The oxidation of nitrosobenzene by nitrogen dioxide in carbon tetrachloride has been re-examined, the rate of reaction exhibiting first-order dependence upon the concentrations of both nitrosobenzene and nitrogen dioxide, with a reactant stoichiometry of 1:1. The rate of reaction is found to be highly sensitive to the presence of trace quantities of water and intensive drying procedures for the solvent have been developed such that the reaction rate could be reduced to a constant level. For nitrosobenzene and a range of substituted nitrosobenzenes the kinetics of the oxidation reaction in carbon tetrachloride have been studied over the temperature range 291-313 K using the stopped flow technique and pseudo-first-order conditions with the nitrogen dioxide in excess. Arrhenius parameters have been obtained for 15 nitrosoarenes and the results obtained are discussed with reference to the Hammett σ constants and the electron population at the nitroso nitrogen as determined by CNDO calculations. It is concluded that the reaction occurs by a radical addition mechanism to the nitroso nitrogen atom giving an unstable aminoxyl intermediate which decomposes rapidly giving the corresponding nitrobenzene and nitric oxide.
Gowenlock, Brian G.,Pfab, Josef,Young, Victor M.
p. 1793 - 1798
(2007/10/03)

Zirconium-catalysed Oxidation of Primary Aromatic Amines to Nitro Compounds Using tert-Butylhydroperoxide
A broad range of primary aromatic amines (1a-x) with electron donating and accepting substituents are oxidized in good to excellent yields to the nitro compounds 3a-x using tert-butylhydroperoxide as the oxidant and Zr(OtBu)4 as the catalyst. The corresponding nitroso compounds 2m,-2n, 2s and 2u can be isolated in the conversion of electron-rich anilines 1m, 1n, 1s and 1u. The aminopyridines 5a-d are also converted to the corresponding nitropyridines 6a-d, but in lower yields (41-47%).
Krohn, Karsten,Kuepke, Jochen,Rieger, Hagen
p. 335 - 339
(2007/10/03)

Iron(III)-catalysed nitration of non-activated and moderately activated arenes with nitrogen dioxide-molecular oxygen under neutral conditions
In the presence of molecular oxygen and a catalytic amount of tris(pentane-2,4-dionato)iron(III), non-activated and moderately activated arenes, which include alkylbenzenes, halogenobenzenes, phenolic ethers, naphthalene and derivatives, can be nitrated with nitrogen dioxide at ice-bath temperature or below to give the corresponding nitro derivatives in fair to good yields. An electron-transfer mechanism has been proposed, where an activated NO2-FeIII complex plays a key role in the cyclic process for converting arenes into nitroarenes.
Suzuki, Hitomi,Yonezawa, Shuji,Nonoyama, Nobuaki,Mori, Tadashi
p. 2385 - 2389
(2007/10/03)