cas 614-00-6, N-NITROSO-N-METHYLANILINE | Articles data

Articles about 614-00-6Total 67 be found

Article title
Article abstract
Author
Journal number and time
Download

Nitrosothiosulphate Ion (S2O3NO-) as a Nitrosating Species
Analysis of rate data obtained for the nitrosation of N-methylaniline in the presence of thiosulphate ion indicates that the nitrosothiosulphate ion is formed and that it acts as a nitrosating species.The bimolecular rate constant for reaction in water at 25 deg C is evaluated as 1.2E4 l mol-1 s-1 from the variation of the observed rate constant with and also as 1.2E4 l mol-1 s-1 from the variation of the observed rate constant with .Results are also reported, for comparison purposes, for the corresponding reactions of nitrosyl bromide and nitrosyl thiocyanate.Nitrosyl bromide (in its reaction with N-methylaniline) is more reactive than the nitrosothiosulphate ion by a factor of ca. 4E-5, and nitrosyl thocyanate is more reactive than the nitrosothiosulphate ion by a factor of ca.1.5E-4.There is also kinetic evidence of nitrosation by the nitrosothiosulphate ion of methanol, hydrazine, and a thiol.The decomposition of S2O3NO(-) follows the rate law -d/dt=k1+k22.This is interpreted in terms of two concurrent reaction pathways, the first involving the formation of the radical anion S2O3-. in a rate-limiting homolysis (followed by rapid dimerisation) and the second a bimolecular reaction of two S2O3NO(-) ions homolysis (followed by rapid dimrisation) and the second a bimolecular reaction of two S2O3NO(-) ions with concurrent S-N bond fission and S-S bond formation yielding the tetrathionate ion S4O6(2-).
Bryant, Tracey,Williams, D. Lyn H.,Ali, M. Hoshair H.,Stedman, Geoffrey
p. 193 - 196
(1986)
Read Online

Kinetic Studies on the Formation of N-Nitroso Compounds IX. Nitrosyl Acetate as a Nitrosating Agent
A study of the nitrosation of N-methylaniline and piperazine by nitrous acid in acetate buffer supports a mechanism covering both reactions, whose effective pathway depends on the relationship between the concentrations of nitrite ion, acetate ion, and nitrosatable substrate.In the case of N-methylaniline the only nitrosating agent is nitrosyl acetate, whereas in the nitrosation of piperazine the nitrous acidium ion and dinitrogen trioxide are also involved.The results obtained seem to show that nitrosation by nitrosyl acetate is diffusion controlled.On this assumpti on, the equilibrium constant of the reaction AcOH + HNO2 AcONO + H2O has been estimated from kinetic measurements as approximately 1.4*E-8 M-1.This means that the concentration of nitrosyl acetate in the medium must be extremely small, which explains the virtual impossibility of detecting it in aqueous solution except by kinetic methods. - (Keywords: Acetate buffer; Kinetics of nitrosation; Nitroso compounds; Nitrosyl acetate)
Casado, Julio,Castro, Albino,Mosquera, Manuel,Prieto, M. Flor Rodriguez,Tato, Jose Vazquez
p. 669 - 682
(1984)
Read Online

One-Pot Tandem ortho-Naphthoquinone-Catalyzed Aerobic Nitrosation of N-Alkylanilines and Rh(III)-Catalyzed C-H Functionalization Sequence to Indole and Aniline Derivatives
The nitroso group served as a traceless directing group for the C-H functionalization of N-alkylanilines, ultimately removed after functioning either as an internal oxidant or under subsequent reducing conditions. The unique ability of o-NQ catalysts to aerobically oxidize the N-alkylanilines without using solvents and stoichiometric amounts of oxidants has rendered the new opportunity to develop the telescoped catalyst systems without a need for directly handling the hazardous N-nitroso compounds.
Si, Tengda,Kim, Hun Young,Oh, Kyungsoo
p. 1152 - 1163
(2021/01/14)

Three-Component Couplings among Heteroarenes, Difluorocyclopropenes, and Water via C-H Activation
Three-component couplings have been realized for efficiently constructing various nitrogen-containing skeletons via C-H activation, where difluorocyclopropenes have been first identified as coupling partners. Many substrates including sp2 and sp3 C-H substrates were well tolerated, furnishing the corresponding products in good yields. Furthermore, a catalyst-dependent reaction was also developed, enabling divergent construction of two different frameworks. The application value of these reactions was demonstrated in gram-scale experiments with as little as 1 mol % catalyst.
Liu, Xuexin,Chen, Jian,Yang, Chunyan,Wu, Zhouping,Li, Zhiyang,Shi, Yuesen,Huang, Tianle,Yang, Zhongzhen,Wu, Yong
supporting information
p. 6831 - 6835
(2021/09/08)

Rhodium-catalyzed tandem acylmethylation/annulation ofN-nitrosoanilines with sulfoxonium ylides for the synthesis of substituted indazoleN-oxides
An atom-economical protocol for synthesizing indazoleN-oxides from readily availableN-nitrosoanilines and sulfoxonium ylides through the rhodium(iii)-catalyzed C-H activation and cyclization reaction is described here. This protocol employs nitroso as a traceless directing group. The transformation features powerful reactivity, tolerates various functional groups, and proceeds with moderate to good yields under an ambient atmosphere, providing a straightforward approach to access structurally diverse and valuable indazoleN-oxide derivatives. Importantly, this new annulation process represents a hitherto unobserved reactivity pattern for theN-nitroso group.
Cui, Xin-F,Huang, Guo-Sh
supporting information
p. 4014 - 4018
(2020/06/09)

Rh(iii)-catalyzed, hydrazine-directed C-H functionalization with 1-alkynylcyclobutanols: A new strategy for 1: H -indazoles
Rh(iii)-catalyzed coupling of phenylhydrazines with 1-alkynylcyclobutanols was realized through a hydrazine-directed C-H functionalization pathway. This [4+1] annulation, based on the cleavage of a Csp-Csp triple bond in alkynylcyclobutanol, provides a new pathway to prepare diverse 1H-indazoles under mild reaction conditions. This journal is
Zhang, Lei,Chen, Junyu,Chen, Xiahe,Zheng, Xiangyun,Zhou, Jian,Zhong, Tianshuo,Chen, Zhiwei,Yang, Yun-Fang,Jiang, Xinpeng,She, Yuan-Bin,Yu, Chuanming
supporting information
p. 7415 - 7418
(2020/07/15)

Substrate promiscuity of ortho-naphthoquinone catalyst: Catalytic aerobic amine oxidation protocols to deaminative cross-coupling and n-nitrosation
ortho-Naphthoquinone-based organocatalysts have been identified as versatile aerobic oxidation catalysts. Primary amines were readily cross-coupled with primary nitroalkanes via deaminative pathway to give nitroalkene derivatives in good to excellent yields. Secondary and tertiary amines were inert to ortho-naphthoquinone catalysts; however, secondary nitroalkanes were readily converted by ortho-naphthoquinone catalysts to the corresponding nitrite species that in situ oxidized the amines to the corresponding N-nitroso compounds. Without using harsh oxidants in a stoichiometric amount, the present catalytic aerobic oxidation protocol utilizes the substrate promiscuity feature to provide a facile access to amine oxidation products under mild reaction conditions.
Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
p. 9216 - 9221
(2019/10/08)

Rhodium(iii)-catalyzed indole synthesis at room temperature using the transient oxidizing directing group strategy
Rh-catalyzed reactions of N-alkyl anilines with internal alkynes at room temperature have been developed using an in situ generated N-nitroso group as a transient oxidizing directing group. Due to mild reaction conditions, this method enabled synthesis of a broad range of N-alkyl indoles, including even two indole-based medicinal compounds. Our work disclosed the feasibility of the transient oxidizing directing group strategy in C-H functionalization reactions, which possesses the potential to enhance overall step-economy and impart new reactivity patterns to substrates.
Shang, Yaping,Jonnada, Krishna,Yedage, Subhash Laxman,Tu, Hua,Zhang, Xiaofeng,Lou, Xin,Huang, Shijun,Su, Weiping
supporting information
p. 9547 - 9550
(2019/08/15)

Synthesis of 2-aminobenzophenones through acylation of anilines with α-oxocarboxylic acids assisted by: Tert -butyl nitrite
In this paper, a regioselective, efficient and convenient synthesis of 2-aminobenzophenones through acylation of anilines with α-oxocarboxylic acids assisted by tert-butyl nitrite is presented. Interestingly, tert-butyl nitrite acts as not only an efficient and mild nitrosation reagent, but also a sustainable oxidant required in the Pd(ii)-catalyzed decarboxylative acylation. Meanwhile, the NO unit turned out to be an easily introduced and readily removable directing group for the regioselective acylation.
Wang, Qianqian,Zhang, Xinying,Fan, Xuesen
p. 7737 - 7747
(2018/11/02)

Direct Transformation of Arylamines to Aryl Halides via Sodium Nitrite and N-Halosuccinimide
A one-pot universal approach for transforming arylamines to aryl halides via reaction with sodium nitrite (NaNO2) and N-halosuccinimide (NXS) in DMF at room temperature under metal- and acid-free condition is described. This new protocol that is complementary to the Sandmeyer reaction, is suggested to involve the in situ generation of nitryl halide induce nitrosylation of aryl amine to form the diazo intermediate which is halogenated to furnish the aryl halide.
Mukhopadhyay, Sushobhan,Batra, Sanjay
supporting information
p. 14622 - 14626
(2018/09/21)

Cp?Rh(iii) catalyzed: Ortho -halogenation of N -nitrosoanilines by solvent-controlled regioselective C-H functionalization
We present a novel, efficient, and regioselective method for the rhodium-catalyzed direct C-H ortho-halogenation of anilines that involves a removable N-nitroso directing group. This method featured mild reaction conditions, wide substrate scope, good functional group tolerance and satisfactory yields. To maintain the high ortho-regioselectivity and conversion, increasing the steric hindrance of the solvent was critical. Preliminary mechanistic studies suggest that C-H activation may be involved in the rate-determining step.
Peng, Qiujun,Hu, Jian,Huo, Jiyou,Yuan, Hongshun,Xu, Lanting,Pan, Xianhua
supporting information
p. 4471 - 4481
(2018/06/29)

Rhodium-catalyzed oxidative C-H/C-H cross-coupling of aniline with heteroarene: N-nitroso group enabled mild conditions
The development of transition metal-catalyzed oxidative C-H/C-H cross-coupling between two (hetero)arenes to forge aryl-heteroaryl motifs under mild conditions is an appealing yet challenging task. Herein, we disclose a rhodium-catalyzed oxidative C-H/C-H cross-coupling reaction of an N-nitrosoaniline with a heteroarene under mild conditions. The judicious choice of the N-nitroso group as a directing group enables heightened reactivity. The coupled products could be transformed expediently to (2-aminophenyl)heteroaryl skeletons.
He, Shuang,Tan, Guangying,Luo, Anping,You, Jingsong
supporting information
p. 7794 - 7797
(2018/07/25)

N-Isocyanodialkylamines generated in situ for the Joullié–Ugi reaction with indolenines
N-Isocyanodialkylamines are rare isocyanide surrogates for the Ugi-type reactions. To avoid problems with instability and the obnoxious smell of these reagents, we optimized and employed a convenient protocol for in situ dehydration of N,N-dialkyl-N′-formyl hydrazines to give the respective N-isocyanodialkylamines which were utilized in the reaction with indolenines and acetic acid. The reaction was demonstrated to give modest to excellent yields of products incorporating the N-isocyanodialkylamine but not the carboxylic acid component.
Golubev, Pavel,Krasavin, Mikhail
supporting information
p. 3532 - 3536
(2018/08/29)

Highly selective sp3 C-N bond activation of tertiary anilines modulated by steric and thermodynamic factors
A highly selective sp3 C-N cleavage of tertiary anilines was achieved using the TBN/TEMPO catalyst system. When N,N-diaklylanilines (alkyl, benzyl) were employed, the N-CH3 bond was selectively cleaved via radical C-H activation. Moreover, when the allyl group was installed, totally reverse selectivity was observed. It is worth noting that the solvent effect is also crucial to obtain high reaction efficiency and selectivity.
Jia, Xiaodong,Li, Pengfei,Shao, Yu,Yuan, Yu,Ji, Honghe,Hou, Wentao,Liu, Xiaofei,Zhang, Xuewen
supporting information
p. 5568 - 5574
(2017/12/06)

Rhodium(III)-Catalyzed Directed C?H Amidation of N-Nitrosoanilines and Subsequent Formation of 1,2-Disubstituted Benzimidazoles
An efficient rhodium-catalyzed direct C?H amidation of N-nitrosoanilines with 1,4,2-dioxazol-5-ones as amidating agents has been developed. This method featured mild reaction conditions, a wide substrate scope and satisfactory yields. Besides, the amidated products could be readily converted to pharmaceutically valuable 1,2-disubstituted benzimidazoles via an HCl-mediated deprotection/cyclization process in one pot.
Chen, Yanyu,Zhang, Rong,Peng, Qiujun,Xu, Lanting,Pan, XianHua
supporting information
p. 2804 - 2808
(2017/10/20)

An efficient synthesis of: N -nitrosamines under solvent, metal and acid free conditions using tert -butyl nitrite
Synthesis of various N-nitroso compounds from secondary amines is reported using tert-butyl nitrite (TBN) under solvent free conditions. Broad substrate scope, metal and acid free conditions, easy isolation procedure and excellent yields are few important features of this methodology. The acid labile protecting groups such as tert-butyldimethylsilyl (TBDMS) and tert-butyloxycarbonyl (Boc) as well as sensitive functional groups such as phenols, olefins and alkynes are found to be stable under the standard reaction conditions. Besides N-nitrosation, TBN is also found to be an efficient reagent in few other transformations including aryl hydrazines to aryl azides and primary amides to carboxylic acids under mild conditions.
Chaudhary, Priyanka,Gupta, Surabhi,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
supporting information
p. 2323 - 2330
(2016/05/19)

Palladium-catalyzed ortho-acylation of N-Nitrosoanilines with α-oxocarboxylic acids: A convenient method to synthesize N-Nitroso ketones and indazoles
An efficient and mild protocol for regioselective synthesis of N-Nitroso aryl ketones by palladium-catalyzed direct acylation of arenes using N-Nitroso as directing groups is described. This reaction proceeded smoothly and could tolerate a variety of functional groups. Moreover, this chemistry offers a convenient access to a range of indazoles.
Zhang, Liang,Wang, Zhe,Guo, Peiyu,Sun, Wei,Li, Ya-Min,Sun, Meng,Hua, Chengwen
supporting information
p. 2511 - 2514
(2016/05/24)

Copper(II)-catalyzed oxidative N-nitrosation of secondary and tertiary amines with nitromethane under an oxygen atmosphere
The combination of a catalytic amount of Cu(OTf)2 and less than a stoichiometric amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under an O2 atmosphere effectively promoted the N-nitrosation of both secondary aromatic/aliphatic amines and tertiary aromatic amines with nitromethane (CH3NO2) leading to the preparation of N-nitrosamine derivatives.
Sakai, Norio,Sasaki, Minoru,Ogiwara, Yohei
supporting information
p. 11638 - 11641
(2015/07/15)

Palladium-catalyzed oxidative C-H bond acylation of N-nitrosoanilines with toluene derivatives: A traceless approach to synthesize N-alkyl-2-aminobenzophenones
A palladium-catalyzed cascade cross-coupling of N-nitroso-anilines and toluene derivatives for the direct synthesis of N-alkyl-2-aminobenzophenones is described. N-nitroso groups in anilines can act as the traceless directing groups while toluene derivatives can serve as effective acyl precursors under mild reaction conditions.
Wu, Yinuo,Feng, Ling-Jun,Lu, Xiao,Kwong, Fuk Yee,Luo, Hai-Bin
supporting information
p. 15352 - 15354
(2015/01/08)

Rhodium(III)-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate for cycloaddition/fragmentation synthesis of indazoles
RhIII-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate allows subsequent construction of indazoles, a privileged heterocycle scaffold in synthetic chemistry, through the exploitation of reactivity between the directing group and installed group. The formal [2+2] cycloaddition/fragmentation reaction pathway identified herein, a unique reactivity pattern hitherto elusive for the N-nitroso group, emphasizes the importance of forward reactivity analysis in the development of useful C-H functionalization-based synthetic tools. The synthetic utility of the protocol is demonstrated with the synthesis of a tri-cyclic-fused ring system. The diversity of covalent linkages available for the nitroso group should enable the extension of the genre of reactivity reported herein to the synthesis of other types of heterocycles.
Chen, Jinsen,Chen, Pei,Song, Chao,Zhu, Jin
supporting information
p. 14245 - 14249
(2015/02/05)

Iodide-catalyzed synthesis of N-nitrosamines via C-N cleavage of nitromethane
An iodide-catalyzed process to synthesize N-nitrosamines has been developed using TBHP as the oxidant. The mild catalytic system succeeded in cleaving the carbon-nitrogen bond in nitromethane. This methodology uses commercially available, inexpensive catalysts and oxidants and has a wide substrate scope and operational simplicity.
Zhang, Jie,Jiang, Jiewen,Li, Yuling,Wan, Xiaobing
p. 11366 - 11372
(2013/12/04)

Traceless directing strategy: Efficient synthesis of N-alkyl indoles via redox-neutral C-H activation
A general protocol for the synthesis of N-alkyl indoles has been developed via a redox neutral C-H activation strategy using a traceless nitroso directing group. A broad scope of substituted N-alkyl indoles has been prepared in good to excellent yields using a very simple Rh catalyst system in the absence of an external oxidant or any other additive. Good to excellent regioselectivity has been achieved for asymmetrically disubstituted acetylenes.
Wang, Chengming,Huang, Yong
supporting information
p. 5294 - 5297
(2013/11/06)

Nitromethane with IBX/TBAF as a nitrosating agent: Synthesis of nitrosamines from secondary or tertiary amines under mild conditions
Aliphatic or aromatic N,N-disubstituted nitrosamine was generated in fair to excellent yield from the reaction of a secondary or tertiary amine with o-iodoxybenzoic acid (IBX) or o-iodosylbenzoic acid (IBA)/R4NX (X = halide) and nitromethane. The product yield was strongly influenced by both the halide of R4NX and iodanes. IBX gave a higher yield than IBA, while the halides follow F- > Cl- > Br- ～ I-. Nitrous acid formed in situ from nitromethane and IBX (or IBA)/halides is likely responsible for the observed reaction.
Potturi, Hima K.,Gurung, Ras K.,Hou, Yuqing
experimental part
p. 626 - 631
(2012/02/16)

Ionic liquid 1-(4-nitritobutyl)-3-methylimidazolium chloride as a new reagent for the efficient N-nitrosation of secondary amines under mild conditions
1-(4-Nitritobutyl)-3-methylimidazolium chloride has been developed as a new reagent for efficient nitrosation of secondary amines at 0 °C to room temperature. A variety of N-nitrosamines were prepared in excellent yields by use of this task-specific ionic liquid under mild and heterogeneous conditions.
Valizadeh, Hassan,Gholipour, Hamid,Shomali, Ashkan
experimental part
p. 467 - 470
(2012/06/15)

1-butyl-3-methylimidazolium nitrite as a reagent for the efficient n-nitrosation of secondary amines
1-Butyl-3-methylimidazolium nitrite, [bmim]NO2 was used as a new effective reagent for the preparation of N-nitrosamines from the corresponding secondary amines at 0 °C to room temperature, under mild conditions in good to excellent yields.
Valizadeh,Gholipour
experimental part
p. 857 - 861
(2012/06/18)

N-nitrosation of secondary amines using p-TSA-NaNO2 as a novel nitrosating agent under mild conditions
A combination of p-toluenesulfonic acid (p-TSA) and sodium nitrite was used as a novel effective nitrosating agent for the N-nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in moderate to excellent yields.
Borikar, Sanjay P.,Paul, Vincent
experimental part
p. 654 - 660
(2011/02/27)

PS-SNAP, a practical polymer-supported nitrosation reagent in organic synthesis
PS-SNAP was designed and evaluated as a practical nitrosating polymer-supported reagent for the nitrosation of sec-amines. Nitrosated dialkyl amines, alkyl anilines, and bis-anilines were obtained in good yields and high purities after shaking the corresponding amines in the presence of an excess of the newly described reagent followed by simple filtration and removal of solvents.
Roche, Didier,Lardy, Claude,Tournier, Lucie,Prunier, Marc,Valeur, Eric
experimental part
p. 2277 - 2280
(2010/05/19)

Photochemical activities of n-nitroso carboxamides and sulfoximides and their application to DNA cleavage
N-Nitroso compounds containing benzene, fluorene or fluorenone rings were synthesized. Photolysis of these compounds with 312-nm UV light provided the NO species, the presence of which was corroborated by use of an EPR method and of 2phenyl-4,4,5,5-tetramethylimidazolin-loxyl 3-oxide (PTIO) as a trapping agent. During irradiation of N-methylN-nitroso-9-fluorenone carboxamide (14c) in the absence of PTIO, it underwent decomposition followed by re-combination to give the heterocyclic nitric oxide radical 15. Incorporation of intercalating moieties endowed the Nnitroso compounds with DNA-cleaving ability through single-strand scission upon UV irradiation in a phosphate buffer (pH 5.0-8.0) under aerobic conditions.
Hwu, Jih Ru,Huang, Joseph Jen Tse,Tsai, Fu-Yuan,Tsay, Shwu-Chen,Hsu, Ming-Hua,Hwang, Kuo Chu,Horng, Jia-Cherng,Ho, Ja An Annie,Lin, Chun-Cheng
scheme or table
p. 8742 - 8750
(2010/03/31)

Bismuth chloride-sodium nitrite: A novel reagent for chemoselective N-nitrosation
Bismuth(III) chloride-sodium nitrite was used as a mild and efficient reagent for N-nitrosation of various tetrazoles, secondary amines, and amides under ambient conditions. Nitrosation took place chemoselectively at the nitrogen atom, giving corresponding N-nitroso derivatives in good to excellent yield. Copyright Taylor & Francis Group, LLC.
Chaskar, Atul C.,Langi, Bhushan P.,Deorukhkar, Amol,Deokar, Hrushikesh
experimental part
p. 604 - 612
(2009/07/04)

Efficient procedure for chemoselective N-nitrosation of secondary amines with trichloromelamine-NaNO2
A combination of trichloromelamine and sodium nitrite in the presence of wet silica gel was used as an effective nitrosating agent for the transformation of secondary amines into the corresponding N-nitroso derivatives under mild and heterogeneous conditions in good to excellent yields.
Bamoniri,Zolfigol,Mirjalili,Fallah
p. 1393 - 1396
(2008/03/27)

Novel nitrosation polymer in organic synthesis
The present invention relates to a novel nitrosation polymer of the formula in which X, Y, R1, R2 and R3 are as defined in claim 1. The invention also relates to a process for the preparation of the said polymer.
-
Page/Page column 7

(2008/06/13)

Tin(IV) chloride-sodium nitrite as a new nitrosating agent for N-nitrosation of amines, amides and ureas under mild and heterogeneous conditions
We have developed a new method of N-nitrosation of various secondary and tertiary amines, amides and ureas using a mixture of tin(IV) chloride and sodium nitrate. This method leads to a selective, high-yielding and mild heterogeneous N-nitrosation by in situ generation of nitrosyl chloride (NOCl). The reaction can be carried out in several different solvents such as chloroform, dichloromethane, ethers, ethyl acetate and alcohols, at room temperature. Georg Thieme Verlag Stuttgart.
Celaries, Benoit,Parkanyi, Cyril
p. 2371 - 2375
(2008/02/03)

Molybdate sulfuric acid/NaNO2: A novel heterogeneous system for the N-nitrosation of secondary amines under mild conditions
Wet molybdate sulfuric acid (=dioxo[bis(sulfato-κO)]molybdenum; MSA), a new solid acid, can be used in combination with sodium nitrite (NaNO 2) to transform a variety of secondary amines to the corresponding N-nitroso compounds under mild, heterogeneous conditions (Table). The process has several advantages: the reagents are inexpensive and non-hazardous, the reaction is clean, fast, and high-yielding, and MSA can be readily removed by filtration and re-used (after treatment with HCl) without loss of activity. Further, only N-nitrosation was observed, but no C- or O-nitrosation.
Montazerozohori, Morteza,Karami, Bahador
p. 2922 - 2926
(2007/10/03)

Dye-sensitized photooxygenation of the C=N bond. 5. Substituent effects on the cleavage of the C=N bond of C-aryl-N-aryl-N-methylhydrazones
The title compounds are cleaved cleanly at the C=N bond by singlet oxygen (1O2, 1Δg) yielding arylaldehydes and N-aryl-N-methylnitrosamines. These reactions take place more rapidly at -78 °C than at room temperature. The effects of substituent variation at both the C-aryl and N-aryl groups were studied using a competitive method. Good correlations of the resulting rate ratios with substituent constants (σ- or σ+) were obtained yielding small to very small ρ values indicative of small to very small changes in charge distribution between the reactant and the rate determining transition state. Electron withdrawing groups on the C-aryl moiety retard reaction somewhat by preferential stabilization of the hydrazone. Electron donors on the other hand slightly stabilize the rate determining transition state. Substituents on the N-aryl group have almost no effect. Inhibition by 3,5-di-tert-butylphenol was not observed showing that free (uncaged) radical intermediates are not involved in the mechanism. We postulate a mechanism in which the initial event is exothermic electron transfer from the hydrazone to 1O2 leading to an ion-radical caged pair. Subsequent covalent bond formation between the hydrazone carbon and an oxygen atom is rate controlling. The transition state for this step also has a lower enthalpy than the starting reactants, but the free energy of activation is dominated by a large negative TΔS? term leading to the negative temperature dependence. Direct formation of a C-O bond in the initial step is not unambiguously ruled out. Subsequent steps lead to C-N cleavage.
Erden, Ihsan,Alscher, Pinar Ergonenc,Keeffe, James R.,Mercer, Colin
p. 4389 - 4392
(2007/10/03)

Dinitrogen tetroxide-impregnated charcoal (N2O 4/charcoal): Selective nitrosation of amines, amides, ureas, and thiols
Efficient N-nitrosation of amines, amides, and ureas, and also S-nitrosation of thiols were performed with dinitrogen tetroxide impregnated on activated charcoal (N2O4/charcoal) in CH 2Cl2 at room temperature. High selectivity was observed for N-nitrosation of dialkyl amines, N-alkylamides and N-alkylureas. Dealkylation and N-nitrosation of trialkylamines were also performed by this reagent. Copyright Taylor & Francis, Inc.
Iranpoor, Nasser,Firouzabadi, Habib,Pourali, Ali Reza
p. 1517 - 1526
(2007/10/03)

Selective N-nitrosation of amines, N-alkylamides and N-alkylureas by N2O4 supported on cross-linked polyvinylpyrrolidone (PVP-N2O4)
N2O4 was supported on the cross-linked polyvinylpyrrolidone (PVP) to afford a solid, stable and recyclable nitrosating agent. This reagent shows excellent selectivity for N-nitrosation of dialkyl amines in the presence of diaryl-, arylalkyl-, trialkylamines and also for secondary amides in dichloromethane at room temperature under mild and heterogeneous conditions. Also N-nitroso-N-alkyl amides can be selectively prepared in the presence of primary amides and N-phenylamides under similar reaction conditions. Selective N-nitrosation or dealkylation and N-nitrosation of tertiary amines can also be performed by this reagent.
Iranpoor, Nasser,Firouzabadi, Habib,Pourali, Ali-Reza
p. 1591 - 1597
(2007/10/03)

A simple and efficient method for the N-nitrosation of secondary amines with NaNO2-Ac2O under mild conditions
Secondary amines can be easily converted into their corresponding nitroso derivations using NaNO2-Ac2O as a nitrosating agent in dichloromethane at room temperature with high yields.
Hou, Jian-Ye,Wang, Yu-Lu,Wang, Jin-Ye
p. 626 - 627
(2007/10/03)

The use of Nafion-H/NaNO2 as an efficient procedure for the chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions
A combination of Nafion-H and sodium nitrite in the presence of wet SiO2 was used as an effective agent for the N-nitrosation of secondary amines under mild and heterogeneous conditions in good to excellent yields.
Zolfigol, Mohammad Ali,Habibi, Davood,Mirjalili, BiBi Fatemeh,Bamoniri, Abdolhamid
p. 3345 - 3349
(2007/10/03)

Silica sulfuric acid/NaNO2 as a novel heterogeneous system for the chemoselective N-nitrosation of secondary amines under mild conditions
Neat chlorosulfonic acid reacts with silica gel to give silica sulfuric acid in which sulfuric acid is immobilized on the surface of silica gel via a covalent bond. A combination of silica sulfuric acid and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in excellent yields.
Zolfigol, Mohammad Ali,Bamoniri, Abdolhamid
p. 1621 - 1624
(2007/10/03)

Nitrosation products from S-nitrosothiols via preliminary nitric oxide formation
High yields of N-nitroso-N-methylaniline were obtained from S-nitrosothiols (RSNO) and N-methylaniline in water at pH 7.4. Reactions were completely inhibited by the presence of EDTA and also when oxygen was removed from the solutions. Lower yields of 4-nitrosophenol were obtained from phenol under similar conditions and there was strong evidence of the rapid formation of a nitroso product (absorbance maximum at 390 nm) from uric acid which decomposed more slowly under the reaction conditions and could not be isolated. The results are consistent with prior nitric oxide formation, by the well-known Cu2+-catalysed (in which the active reagent is Cu+) decomposition of the S-nitrosothiol, subsequent oxidation of NO yielding NO2, which reacts further with NO to give N2O3, which then effects conventional electrophilic nitrosation in direct competition with its hydrolysis to nitrite. With phenol as the reactant, higher yields of 4-nitrosophenol were only possible when there was a very large excess of phenol over RSNO, probably due to the more effective relative competition of the hydrolysis reaction, given the lower reactivity in nitrosation of phenol compared with N-methylaniline. Nitrosation of uric acid is unknown, but we were able to observe the fairly rapid build-up of the same absorbance at 390 nm, from uric acid and nitrous acid only at around pH 4, which disappeared more slowly. The results suggest that uric acid behaves as do amides generally in that a nitroso compound is formed, which decomposes by an acid-catalysed route.
Noble, Darren R.,Williams, D. Lyn H.
p. 1834 - 1838
(2007/10/03)

Kinetics and mechanism of the formation and reactions of S-nitroso derivatives of some heterocyclic thiones
Rate and equilibrium measurements have been obtained for the nitrosation (using nitrous acid in dilute acid aqueous solution) of the following thione-thiol nitrogen heterocyclic species and for the decomposition reactions of the formed S-NO- io
Amado,Blakelock,Holmes,Williams
p. 441 - 447
(2007/10/03)

Structural features of aliphatic N-nitrosamines of 7-azabicyclo[2.2.1]heptanes that facilitate N-NO bond cleavage
N-Nitrosamines can be considered as potential nitric oxide (NO)/nitrosonium ion (NO+) donors. However, the relation of the structures of N-nitrosamines, in particular of aliphatic N-nitrosamines, to the characteristics of release of NO or NO+ remains unclear. Here we show that aliphatic N-nitrosoamines of 7-azabicyclo[2.2.1]heptanes can undergo heterolytic N-NO bond cleavage. On the basis of the observation of reduced rotational barriers of the N-NO bonds in solution and nitrogen-pyramidal structures of the N-nitroso group in the solid state, we postulate that N-NO bond cleavage of N-nitrosamines is enhanced by a reduction of the resonance in the N-NO group. Computational studies suggest that these structural features of the N-nitrosamines of 7-azabicyclo[2.2.1]heptane are derived from angle strain imposed on the CNC angles.
Ohwada,Miura,Tanaka,Sakamoto,Yamaguchi,Ikeda,Inagaki
p. 10164 - 10172
(2007/10/03)

Reaction of secondary and tertiary amines with nitric oxide in the presence of oxygen
In order to clarify the role of oxygen in the reaction of amines with nitric oxide, secondary amines were allowed to react with nitric oxide in the presence of oxygen. Although N-nitrosamines were obtained as the main products in every case, the yields depended on the substituents and reaction solvents. Detailed investigation revealed that the reaction proceeded by at least two pathways: one involving oxygen as a catalyst, and the other consuming the stoichiometric amount of oxygen. Both paths afforded the same nitroso adducts. It was suggested that a third path, a catalytic process via Drago's salts was also possible. The same reaction was applied to a tertiary amine, and it was found that the oxygen was consumed stoichiometrically in this case.
Itoh, Takashi,Matsuya, Yuji,Maeta, Hiromi,Miyazaki, Michiko,Nagata, Kazuhiro,Ohsawa, Akio
p. 819 - 823
(2007/10/03)

Effect of oxygen on the reaction of secondary amines with nitric oxide
Secondary amines were allowed to react with nitric oxide in the presence of oxygen to afford N-nitrosamines in good yields. Detailed investigation revealed that the reaction proceeded by two pathways; the one involves the catalytic behavior of oxygen, and the other consumes a stoichiometrical amount of oxygen. Both pathways afforded the same nitroso adducts.
Itoh, Takashi,Matsuya, Yuji,Maeta, Hiromi,Miyazaki, Michiko,Nagata, Kazuhiro,Ohsawa, Akio
p. 133 - 135
(2007/10/03)

Nitrosation of Amines in Nonaqueous Solvents. 3. Direct Observation of the Intermediate in Cyclohexane
The reactions of N-methylaniline (MeAn) with 2,2-dichloroethylnitrite (DCEN) and 2,2,2-trichloroethylnitrite (TCEN) in cyclohexane, and N-methylmethoxyamine (MMA) with TCEN in the same solvent, all gave the expected N-nitrosamines. Spectrophotometric monitoring of the MeAn/DCEN and MMA/TCEN reactions showed accumulation of the reaction intermediate. These are the first nitrosations of amines by alkyl nitrites in which observation of the intermediate has been possible; this is attributed to the low basicity of these amines (a) having effectively eliminated the possibility of the intermediate decomposing by base catalysis and (b) having decreased the rate of spontaneous decomposition of the intermediate more than the rate of its formation. Because of the scant capacity of cyclohexane to stabilize charge, it is assumed that both the formation and decomposition of the intermediate occur via concerted mechanisms with four-center transition states: formation through nucleophilic attack by the amine on the nitroso group accompanied by transfer of the amine proton to this group, decomposition through simultaneous cleavage of the N-O bond, and protonation of the alkoxide leaving group.
Boni,Garcia-Rio,Leis,Moreira
p. 8887 - 8892
(2007/10/03)

Stability and nitrosation efficiency of substituted N-methyl-N-nitrosobenzenesulfonamides
A series of substituted N-methyl-N-nitrosobenzenesulfonamides [2,4,6-(CH3)3, 4-CH3O, 4-CH3 4-Cl and 4-NO2] were synthesized. All of them transfer their nitroso group to N-methylaniline in a quantitative manner, the more reactive being those substituted with electron-withdrawing groups, thus resembling some of the known alkyl nitrites. Studies of their acid denitrosation and base-catalysed hydrolysis demonstrated that the nitrosobenzenesulfonamides are fairly stable in aqueous media between pH 2 and 11. Their relative stability in aqueous media together with their ability to transfer the nitroso group to nucleophiles suggest their use as excellent alternatives to alkyl nitrites in both neutral and basic media.
Garcia-Rio,Leis,Moreira,Norberto
p. 756 - 760
(2007/10/03)

Kinetics and mechanism of the nitrosation of 2-mercaptopyridine [pyridine-2(1H)-thione]
2-Mercaptopyridine (MP) reacts rapidly with nitrous acid in mildly acid aqueous solution (via the thione tautomer) to give an unstable 5-nitroso ion (SNO+) in a reversible process with an equilibrium constant (KN) of ca. 1 × 105 dm6 mol-2. SNO+ is readily detected by two peaks in the UV spectrum at 295 and 240 nm with extinction coefficients 9600 and 9300 dm3 mol-1 cm-1 respectively. MP is regenerated when the solution is made alkaline. Kinetic measurements made on the nitrosation reaction give a value of 8200 dm6 mol-2 s-1 for the third order rate constant k3 (defined by rate = k3 [MP] [HNO2] [H+]), which is close to that believed to be the diffusion-controlled limit for attack by NO+ (or H2NO2+). As expected there is marked catalysis by Cl- and Br-, and analysis of the kinetic results obtained from variation of measured rate constants with [halide ion] gave values of 3.5 × 109 and 3.7 × 109 dm3 mol-1 s-1 respectively for the bimolecular rate constants for NOCl and NOBr reactions with MP, again values close to the diffusion limit. The same experimental results also yielded values of 30 and 2400 dm3 mol-1 s-1 for the second order rate constants, for the reverse process of Cl- and Br- reaction with SNO+. Values for KN of 1.3 × 105 and 7.9 × 104 dm6 mol-2 were obtained from the halide catalysed reactions. In acid solution SNO+ decomposed to the disulfide (2,2′-dipyridyl disulflde) and NO (measured with a NO-electrode). Quenching of SNO+ at pH 7.4 gave UV spectroscopic evidence for the neutral deprotonated form (SNO) of SNO+ and there was a transformation to give mainly MP together with some disulfide. There was clear evidence that SNO+ (and maybe SNO) can act as an efficient nitrosating species: addition of the thiol N-acetylcysteine (at pH 6.15) resulted in the almost instantaneous decomposition of SNO. Addition of N-methylaniline (NMA) to an acidified solution of SNO+ resulted in quantitative N-methyl-N-nitrosoaniline formation and kinetic measurements of the nitrosation of NMA in the presence of MP showed marked catalysis at low [MP], which disappeared at higher [MP]. These results are quantitatively consistent with nitrosation via SNO+: catalysis disappears at higher [MP] when the nitrous acid is virtually completely converted to SNO+. A value of 1.7 × 105 dm3 mol-1 s-1 was obtained for the bimolecular rate constant for reaction of SNO+ with the free base form of NMA. MP is thus an excellent catalyst for electrophilic nitrosation. Under somewhat different conditions SNO+ can then act as a source of HNO2/NO2-, NO or NO+. The chemistry reported in this paper bears many similarities to that involved in the nitrosation of thioureas, and subsequent reactions of the S-nitrosothiouronium ions.
Amado, Severino,Dicks, Andrew P.,Williams, D. Lyn H.
p. 1869 - 1875
(2007/10/03)

Observation of a single-pot aromatic reductive denitration
4,N,N-Trimethyl-3-nitrobenzenamine gave reductive denitration products (ca. 28%) upon treatment with n-butyl nitrite in the presence of catalytic amounts of ammonium chloride and water in an unprecedented one-reagent single-pot process. The three isomeric N,N-dimethylnitrobenzenamines showed the same behaviour to a much lesser extent; the ortho isomer was partially (7%) transformed into 1-methylbenzotriazole.
Giumanini, Angelo G.,Verardo, Giancarlo
p. 469 - 473
(2007/10/03)

S-nitrosation of proteins by N-methyl-N-nitrosoanilines
-
Guo Zhengmao,McGill,Yu Libing,Li Jun,Ramirez,Wang
p. 573 - 578
(2007/10/03)

Reactions of Nitric Oxide with Amines in the Presence of Dioxygen
Nitric oxide (NO), a multifaceted bioregulatory agent and an environmental pollutant, can effectively convert aromatic amines to the corresponding triazenes under aerobic conditions, but not under anaerobic conditions.Nucleic acid bases and nucleosides are also determinated via hydrolysis of the diazonium ion products with exposure to aerobic NO solution.A peroxynitrite radical or nitrogen dioxide is suggested to be the ultimate reactive species.
Nagano, Tetsuo,Takizawa, Hiromasa,Hirobe, Masaaki
p. 8239 - 8242
(2007/10/02)

Transnitrosation by N-aryl-N-nitrosoureas; NO-carrying O-nitrosoisourea
Transfer of nitroso groups, so-called transnitrosation, from aromatic N-nitroso compounds such as N-nitrosoureas, N-nitrosamides and N-nitrosamines, to aromatic amines or ureas was observed under non-acidic conditions at room temperature. Sterically hindered 3,3-dibenzyl-1-(4-tolyl)-1-nitrosourea (1a) rapidly nitrosates indoline, N-alkylanilines or 3-methyl-1-(4-tolyl)urea to give their N-nitroso derivatives. In the case of N,N-dimethylanilines, nitrosative demethylation occurs to give N-methyl-N-nitrosanilines. The transnitrosation is accelerated by electron-releasing groups on the nitroso acceptors, N-alkylanilines. The transnitrosation mechanism is considered to be as follows: N-nitrosourea (1) thermally decomposes to nitric oxide and ureidyl radical followed by formation of an O-nitrosoisourea intermediate (10), which acts as an NO-carrying agent and nitrosates anilines or ureas.
Tanno,Sueyoshi,Miyata
p. 1760 - 1767
(2007/10/02)

The mild N-nitrosation of secondary amines with trichloro nitromethane
Reaction of trichloronitromethane with secondary amine leads to the formation of corresponding carcinogeneous N-nitrosamines under mild conditions.
Demir,Mahasneh,Aksoy,Gercek
p. 2607 - 2611
(2007/10/02)