- Regioselective nitration of anilines with Fe(NO3)3·9H2O as a promoter and a nitro source
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An efficient Fe(NO3)3·9H2O promoted ortho-nitration reaction of aniline derivatives has been developed. This reaction may go through a nitrogen dioxide radical (NO2) intermediate, which is generated by the thermal decomposition of iron(iii) nitrate. The practicality of the present method using nontoxic and inexpensive iron reagents has been shown by the broad substrate scope and applications.
- Gao, Yang,Mao, Yuanyou,Zhang, Biwei,Zhan, Yingying,Huo, Yanping
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supporting information
p. 3881 - 3884
(2018/06/08)
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- Regioselective ortho-nitration of N-phenyl carboxamides and primary anilines using bismuth nitrate/acetic anhydride
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An efficient and one-pot synthetic method for the regioselective ortho-nitration of the N-phenyl carboxamides and primary anilines has been developed by using bismuth nitrate and acetic anhydride as the nitrating reagents. Reaction proceeds at room temperature and results in corresponding ortho-nitrated products in moderate to excellent yields. This method provides an operationally simple, regioselective, and efficient access to synthesize o-nitro anilines under the mild conditions.
- Lu, Yang,Li, Yaming,Zhang, Rong,Jin, Kun,Duan, Chunying
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supporting information
p. 9422 - 9427
(2013/10/08)
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- Synthesis of benzimidazoles by phosphine-mediated reductive cyclisation of ortho-nitro-anilides
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Heating ortho-nitro-anilides 1-3 and 2-methyl-N-(3-nitropyridin-2-yl) propanamide (5) with 4 equiv. of a phosphine led to the 2-substituted benzimidazoles 6-8 and to the imidazo[4,5-b]pyridine 10, respectively, in yields between 45 and 85%. Heating 1 with (EtO)3P effected cyclisation and N-ethylation, leading to the 1-ethylbenzimidazole 6b. The slow cyclisation of the N-pivaloylnitroaniline 2b allowed isolation of the intermediate phosphine imide 11 that slowly transformed into the 1H-benzimidazole 7b. The structure of 11 was established by crystal-structure analysis. While the N-methylated ortho-nitroacetanilide 3 cyclised to the 1,2-dimethyl-1H-benzimidazole (8), the 2-methylpropananilide 4 was transformed into 1-methyl-3-(1-methylethyl)-2H- benzimidazol-2-one (9).
- Duchek, Jan,Vasella, Andrea
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experimental part
p. 977 - 986
(2011/08/05)
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- A direct, regioselective palladium-catalyzed synthesis of N-substituted benzimidazoles and imidazopyridines
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Unsymmetric, N-substituted benzimidazoles and imidazopyridines can be prepared directly from 2-halonitroarenes and amides through Pd(TFA) 2/(R)-BINAP-catalyzed cross-coupling and subsequent reductive aminocyclization. This sequence can be conducted by a one-pot procedure. The method is versatile and allows the straightforward, regioselective preparation of these important nitrogen heterocycles. Unsymmetrical, N-substituted benzimidazoles can be prepared directly from 2-halonitroarenes and amides through Pd(TFA)2/(R)-BINAP-catalyzed cross-coupling and subsequent reductive aminocyclization.This sequence can be conducted by a one-pot procedure. The method is versatile and allows the straightforward, regioselective preparation of these important nitrogen heterocycles. Copyright
- Alonso, Jorge,Halland, Nis,Nazare, Marc,R'Kyek, Omar,Urmann, Matthias,Lindenschmidt, Andreas
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supporting information; experimental part
p. 234 - 237
(2011/03/20)
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- On the active site for hydrolysis of aryl amides and choline esters by human cholinesterases
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Cholinesterases, in addition to their well-known esterase action, also show an aryl acylamidase (AAA) activity whereby they catalyze the hydrolysis of amides of certain aromatic amines. The biological function of this catalysis is not known. Furthermore, it is not known whether the esterase catalytic site is involved in the AAA activity of cholinesterases. It has been speculated that the AAA activity, especially that of butyrylcholinesterase (BuChE), may be important in the development of the nervous system and in pathological processes such as formation of neuritic plaques in Alzheimer's disease (AD). The substrate generally used to study the AAA activity of cholinesterases is N-(2-nitrophenyl)acetamide. However, use of this substrate requires high concentrations of enzyme and substrate, and prolonged periods of incubation at elevated temperature. As a consequence, difficulties in performing kinetic analysis of AAA activity associated with cholinesterases have hampered understanding this activity. Because of its potential biological importance, we sought to develop a more efficient and specific substrate for use in studying the AAA activity associated with BuChE, and for exploring the catalytic site for this hydrolysis. Here, we describe the structure-activity relationships for hydrolysis of anilides by cholinesterases. These studies led to a substrate, N-(2-nitrophenyl)trifluoroacetamide, that was hydrolyzed several orders of magnitude faster than N-(2-nitrophenyl)acetamide by cholinesterases. Also, larger N-(2-nitrophenyl)alkylamides were found to be more rapidly hydrolyzed by BuChE than N-(2-nitrophenyl)acetamide and, in addition, were more specific for hydrolysis by BuChE. Thus, N-(2-nitrophenyl)alkylamides with six to eight carbon atoms in the acyl group represent suitable specific substrates to investigate further the function of the AAA activity of BuChE. Based on the substrate structure-activity relationships and kinetic studies, the hydrolysis of anilides and esters of choline appears to utilize the same catalytic site in BuChE.
- Darvesh, Sultan,McDonald, Robert S.,Darvesh, Katherine V.,Mataija, Diane,Mothana, Sam,Cook, Holly,Carneiro, Karina M.,Richard, Nicole,Walsh, Ryan,Martin, Earl
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p. 4586 - 4599
(2007/10/03)
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- Process for producing N-acylnitroaniline derivative
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A process of reacting a nitroaniline compound of formula (2); with acid anhydride or acid chloride is carried out in the presence of an alkali metal compound or an alkaline earth metal compound to produce acylnitroaniline derivative. The process further includes the step of reacting the resulting product with a compound of formula (5);R2-Y to produce an N-acylnitroaniline derivative of formula (1);
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- Process for producing N-acylnitroaniline derivative
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A process of reacting a nitroaniline compound of formula (2); with acid anhydride or acid chloride is carried out in the presence of an alkali metal compound or an alkaline earth metal compound to produce acylnitroaniline derivative. The process further includes the step of reacting the resulting product with a compound of formula (5); R2—Y ??(5) to produce an N-acylnitroaniline derivative of formula (1);
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- Trapping of translocated radicals by tetrathiafulvalene radical cation
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Aryl radicals are generated by electron transfer from tetrathiafulvalene to arenediazonium salts.The aryl radicals are translocated into alkyl radicals which undergo a C-S or C-C bond formation to tetrathiafulvalene radical cation, depending on the nucleophilicity/electrophilicity of the translocated carbon radical.
- Murphy, John A.,Roome, Stephen J.
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p. 1349 - 1358
(2007/10/02)
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- Ozone-mediated Reaction of Anilides and Phenyl Esters with Nitrogen Dioxide: Enhanced Ortho-reactivity and Mechanistic Implications
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In the presence of ozone, anilides 1 can be nitrated rapidly with nitrogen dioxide in chloroform at 0 deg C to give a high proportion of ortho-nitro derivatives (ortho:para = 1.2-4.4) in good yields.The phenyl esters 15 can be similarly nitrated on the aromatic ring without significant cleavage of the ester bond, giving a mixture of isomeric nitro derivatives in which the ortho-isomer predominantes (ortho:para = 1.1-1.5).The oridin of the enhanced ortho reactivity is discussed in terms of an electron-transfer process involving the nitrogen trioxide as initial electrophile.
- Suzuki, Hitomi,Tatsumi, Atsuo,Ishibashi, Taro,Mori, Tadashi
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p. 339 - 344
(2007/10/02)
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