- Rhodium(iii)-catalyzed indole synthesis at room temperature using the transient oxidizing directing group strategy
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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
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supporting information
p. 9547 - 9550
(2019/08/15)
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- Regioselective Nitration of N-Alkyl Anilines using tert-Butyl Nitrite under Mild Condition
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Regioselective ring nitration of N-alkyl anilines is reported using tert-butyl nitrite. The reactions proceed efficiently with a wide range of substrates providing synthetically useful N-nitroso N-alkyl nitroanilines in excellent yields which can be easily converted into N-alkyl phenylenediamines and N-alkyl nitroanilines using Zn-AcOH and HCl/MeOH, respectively.
- Chaudhary, Priyanka,Gupta, Surabhi,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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p. 104 - 119
(2019/01/08)
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- 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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- Cp?Rh(iii) catalyzed: Ortho -halogenation of N -nitrosoanilines by solvent-controlled regioselective C-H functionalization
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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
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supporting information
p. 4471 - 4481
(2018/06/29)
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- Highly selective sp3 C-N bond activation of tertiary anilines modulated by steric and thermodynamic factors
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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
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supporting information
p. 5568 - 5574
(2017/12/06)
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- Copper(II)-catalyzed oxidative N-nitrosation of secondary and tertiary amines with nitromethane under an oxygen atmosphere
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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
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supporting information
p. 11638 - 11641
(2015/07/15)
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- Rhodium(III)-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate for cycloaddition/fragmentation synthesis of indazoles
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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
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supporting information
p. 14245 - 14249
(2015/02/05)
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- Iodide-catalyzed synthesis of N-nitrosamines via C-N cleavage of nitromethane
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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
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p. 11366 - 11372
(2013/12/04)
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- Rhodium(III)-catalyzed N-nitroso-directed C-H olefination of arenes. High-yield, versatile coupling under mild conditions
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N-Nitroso compounds are a versatile class of organic structures that allow expedient access to a diversity of synthetically useful architectures through demonstrated reactivities. We report herein the development of a Rh(III)-catalyzed N-nitroso-directed
- Liu, Baoqing,Fan, Yang,Gao, Yang,Sun, Chao,Xu, Cheng,Zhu, Jin
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supporting information
p. 468 - 473
(2013/02/23)
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- Ionic liquid 1-(4-nitritobutyl)-3-methylimidazolium chloride as a new reagent for the efficient N-nitrosation of secondary amines under mild conditions
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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
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experimental part
p. 467 - 470
(2012/06/15)
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- 1-butyl-3-methylimidazolium nitrite as a reagent for the efficient n-nitrosation of secondary amines
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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
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experimental part
p. 857 - 861
(2012/06/18)
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- Nitroxyl progenitor compounds and methods of use
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Described herein are nitroxyl progenitor compounds, and compositions including, and methods or generating, the compounds thereof, and methods of treating or preventing disease and disease symptoms using the compounds and compositions.
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Page/Page column 13-14
(2009/12/04)
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- The mechanistic origin of regiochemical changes in the nitrosative N-dealkylation of N,N-dialkyl aromatic amines
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The regioselectivity of the nitrous acid mediated dealkylation of 4-substituted-N-ethyl-N-methylanilines is a function of the acidity of the reaction mixture. At high acidity deethylation predominates, whereas demethylation is the predominant reaction in nitrosamine formation at pH 2 and above. In some cases the regioselectivity of nitrosative dealkylation changes as the run proceeds. Through the use of the corresponding 4-nitroaniline as the primary substrate, CIDNP, kinetics, kinetic deuterium isotope effects and other transformations involving nitrosations with NO2 or NOBF4 in aprotic solvents, a new mechanism of tertiary amine nitrosation has been deduced and proposed to explain regioselective deethylation. The mechanism involves the oxidation of the substrate to the amine radical cation by NO +. This is followed by the abstraction of a hydrogen atom from the carbon adjacent to the amine nitrogen by NO2 to produce an iminium ion which reacts further to produce the corresponding aldehyde and the nitrosamine. Depending upon the acidity, this process competes with three other mechanistic pathways, two of which give the nitrosamine through the iminium ion, and one leads to the formation of C-nitro compounds. The competing pathways to nitrosamine formation involve NOH elimination from a nitrosammonium ion and deprotonation of the radical cation to give an α-amino radical which rapidly oxidized to the iminium ion. Predominant, but not highly regioselective demethylation occurs by these pathways. Nitro compound formation principally arises from the reaction of NO2 with the radical cation followed by deprotonation, but also occurs by para C-nitrosation followed by oxidation. The Royal Society of Chemistry 2005.
- Teuten, Emma L.,Loeppky, Richard N.
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p. 1097 - 1108
(2007/10/03)
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- Reaction of secondary and tertiary amines with nitric oxide in the presence of oxygen
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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
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p. 819 - 823
(2007/10/03)
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- Effect of oxygen on the reaction of secondary amines with nitric oxide
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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
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p. 133 - 135
(2007/10/03)
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- Energetic binders
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Liquid nitromalonate polyesters and methods for their preparation are disclosed. Solid propellants are provided which employ as the binder a nitromalonate polyester. These propellants are resistant to plasticizer syneresis and crystallization and provide
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- By-products in the rearrangement of N-methyl-N-phenylnitramine
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N-Methyl-N-phenylnitramine was rearranged in the aqueous dioxane- sulphuric acid mixture to 2-nitro- and 4-nitro-N-methylanilines. The isomer ratio was independent of the acidity within the range of -0.3 > H(o) > -2.8. Some by-products were isolated and i
- Daszkiewicz, Zdzislaw,Nowakowska, Ewa,Kyziol, Janusz B.
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p. 5991 - 6000
(2007/10/03)
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- Photolysis of some N-nitroso- and N-nitro-anilines in solution
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The photolyses of three N-methyl-N-nitrosoanilines and two N-methyl-N-nitroanilines in organic solvents have been studied in the range of 300-340 nm. The influence of solvent character and the presence or absence of oxygen play important roles in the product composition range. The primary photochemical process involves N-N fission, this being homolytic in aprotic solvents and heterolytic in methanol. Three novel mechanistic conclusions are proposed, namely photosolvolysis of a nitrosamine in methanol, photooxidation of nitrosamines in aprotic solvents and the production of biphenyl derivatives on photolysis of nitro-substituted nitrosamines and nitramines in aromatic solvents.
- Gowenlock, Brian G.,Pfab, Josef,Young, Victor M.
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p. 915 - 919
(2007/10/03)
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- Observation of a single-pot aromatic reductive denitration
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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
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p. 469 - 473
(2007/10/03)
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- Transnitrosation by N-aryl-N-nitrosoureas; NO-carrying O-nitrosoisourea
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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
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p. 1760 - 1767
(2007/10/02)
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- Pressure Effects on the Thermal Decomposition of Nitramines, Nitrosamines, and Nitrate Esters
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Solutions of nitramine and nitrate ester explosives and model compounds were thermolyzed at various hydrostatic pressures and their rates of decomposition were measured.The effects of pressure on their rates were used to infer the mechanism of their initi
- Naud, Darren L.,Brower, Kay R.
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p. 3303 - 3308
(2007/10/02)
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- N-Dealkylation-N-nitrosation of Tertiary Aromatic Amines by n-Butyl Nitrite
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N,N-Dialkyl aromatic amines with a variety of ring substituents are N-dealkylated and N-nitrosated efficiently by n-butyl nitrite/ammonium chloride/water at reflux temperature.Ring nitrosation was never observed, but minor amounts of m- and p-nitro amines and/or nitrosamines were formed in some cases.Ring nitration is rather a reaction of the initial substrate than a process occurring on formed nitrosamines.The leaving propensities of the initial N-substituents to yield nitrosamines were in the order benzyl >> methyl >> alkyl.Key Words: Nitrosamines; N-Dealkylation; N-Nitrosation; C-Nitration; Alkyl nitrite.
- Verardo, Giancarlo,Giumanini, Angelo G.,Strazzolini, Paolo
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p. 7845 - 7852
(2007/10/02)
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- AROMATIC TERTIARY AMINES AND n-BUTYL NITRITE
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The reaction between alkyl nitrites, particularly n-butyl nitrite, and tertiary aromatic amines under a variety of experimental conditions promptly yielded products of N-dealkylation-N-nitrosation, ring nitration, ipso-substitution and, occasionally, combinations of these processes.Aminoethers were detected as final products and intermediates on the way to N-nitrosations.Reaction pathways are suggested for some of the observed behaviours on the basis of experimental evidences whereas other alternatives are discarded.
- Varardo, Giancarlo,Giumanini, Angelo G.,Strazzolini, Paolo
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p. 4303 - 4332
(2007/10/02)
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- Unusual Rate-limiting Proton Transfer in the Acid-catalysed Reactions of N-Nitroso Compounds
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For both N-methyl-N-nitrosoaniline and N-nitrosodiphenylamine, the catalytic effect of halide ion, thiocyanate ion, and thiourea in the denitrosation reaction in acid solution disappears at high nucleophile concentrations.This suggests a change to an earlier rate-limiting step.The data, including the variation of rate constant with acidity, are quantitatively in accord with a reaction mechanism involving protonation of the nitosamine followed by nucleophilic attack, either stage being rate limiting, depending on the reactivity and concentration of the nucleophile.The kinetic solvent isotope effect kH2O/kD2O decreases from 1.59 at 0.43M-thiourea to 0.71 at 0.015M-thiourea, which is consistent with a change from general acid catalysis at high to specific hydrogen ion catalysis at low .Substituent effects at the amino-nitrogen atom and also in the 4-position of a phenyl substituent are very amall, the largest effect being a three-fold reduction in rate constant effected by a 4-NO2 group.These results are in accord with the known dipolar nature of nitrosamines.There is a close analogy between this system and the acid-catalysed cleavage reaction of carbamate derivatives.A similar mechanism is proposed involving a pre-association of the reactants forming a hydrogen-bonded intermediate.
- Al-Kaabi, Sharifa S.,Hallett, Geoffrey,Meyer, Thomas A.,Williams, D. Lyn H.
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p. 1803 - 1808
(2007/10/02)
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- A Kinetic Investigation of the Thionitrite from (+/-)-2-Acetylamino-2-carboxy-1,1-dimethylethanethiol as a Possible Nitrosating Agent
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In strongly aqueous acid solution (+/-)-2-acetylamino-2-carboxy-1,1-dimethylethyl thionitrite (RSNO) undergoes denitrosation to give the corresponding thiol.The reaction is reversible and normally lies well over on the side of the thionitrite, but can proceed in the denitrosation direction in the presence of traps for free nitrous acid such as added sodium azide or sulphamic acid.At sufficiently high trap concentration to ensure complete irreversibility, the reaction was found to be first-order in RSNO and acid-catalysed; the observed reaction rate constant is approximately proportional to h0.Catalysis was observed by Cl(1-), Br(1-), SCN(1-), and SC(NH2)2 and the second-order rate constants were 4.6*10-3, 13.0*10-3, 34*10-3, and 27*10-3 l mol-1s-1, respectively.The order of reactivity is as expected with the exception of that of thiourea.N-Methyl-4-nitroaniline was converted quantitatively to the corresponding nitrosamine by RSNO, but in the presence of added sodium azide, no nitrosamine was detected; this shows that RSNO like nitrosamines generally and alkyl nitrites, acts as a nitrosating agent towards amines etc., under these experimental conditions, by prior hydrolysis or via nitrosyl halide etc. formation.A kinetic analysis has enabled the reactivity of the nitrous acid traps hydrazoic acid and sulphamic acid to be established quantitatively.
- Al-Kaabi, Sharifa S.,Williams, D. Lyn H.,Bonnett, Raymond,Ooi, Suan L.
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p. 227 - 230
(2007/10/02)
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