- Reactions of Nitrosoureas and Related Compounds in Dilute Aqueous Acid: Transnitrosation to Piperidine and Sulfamic Acid
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The transnitrosation reactions of four classes of nitrosamides in dilute aqueous acid were studied.Trialkyl nitrosoureas and nitrosoguanidines were found to react very rapidly in transnitrosations to piperidine, giving high yields (70-90percent) of nitrosopiperidine at pH 1.7 (perchloric acid) or pH 3.3 (formate buffer).Methylnitrosourea reacted more slowly than either the trialkylnitrosoureas or the nitrosoguanidines and gave moderate yields (48percent) of nitrosopiperidine at pH 1.7 and low yields (6percent) at pH 3.3.Nitrosourethanes gave high yields at pH 1.7 and moderate yields at pH 3.3.Denitrosation rates (transnitrosation to a nitrite trap) are given for a series of monoalkyl- and trialkylnitrosoureas.An increase in the size of the alkyl group at N1 decreased the rate of denitrosation.The kinetics of nucleophile-catalyzed transnitrosation from trialkylnitrosoureas to piperidine at pH 1.7 for a series of four trialkylnitrosoureas have been studied.Both the denitrosation of the donor and the nitrosation of the recipient were studied with respect to thiocyanate ion concentration.The denitrosation step was affected only at high , while the nitrosation step showed a first-order dependence on thiocyanate at most concentrations, with a "leveling off" effect observed at high .The denitrosation step does not exhibit a true dependence on thiocyanate concentration but merely reflects the rapid rate of the nitrosation of the recipient piperidine at high as a consequence of mass action.The behavior of nitrosoureas in transnitrosation reactions is compared with that of alicyclic nitrosamines.The latter differ from nitrosoureas in that they react more slowly, require a nucleophilic cataly sis at the denitrosation step, and do not always nitrosate strongly basic amines.
- Singer, Sandra S.,Cole, Barbara B.
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- Efficient procedure for chemoselective N-nitrosation of secondary amines with trichloromelamine-NaNO2
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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
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p. 1393 - 1396
(2008/03/27)
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- Alumina-methanesulfonic acid (AMA)/NaNO2 as an efficient procedure for the chemoselectivite N-nitrosation of secondary amines
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A combination of alumina/methanesulfonic acid (AMA) and sodium nitrite was used as an effective nitrosating agent for the nitrosation of secondary amines under mild and heterogeneous conditions in good to excellent yields. Copyright Taylor & Francis Group, LLC.
- Niknam, Khodabakhsh,Zolfigol, Mohammad Ali
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p. 2311 - 2319
(2007/10/03)
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- The use of Nafion-H/NaNO2 as an efficient procedure for the chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions
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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
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p. 3345 - 3349
(2007/10/03)
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- Silica sulfuric acid/NaNO2 as a novel heterogeneous system for the chemoselective N-nitrosation of secondary amines under mild conditions
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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
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p. 1621 - 1624
(2007/10/03)
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- Trichloroisocyanuric acid/NaNo2 as a novel heterogeneous system for the N-nitrosation of N,N-dialkylamines under mild conditions
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A combination of trichloroisocyanuric acid and sodium nitrite in the presence of wet SiO2 was used as an effective nitrosating agent for the nitrosation of N,N-dialkyl amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in moderate to excellent yields.
- Zolfigol, Mohammad Ali,Choghamarani, Arash Ghorbani,Hazarkhani, Hassan
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p. 1002 - 1004
(2007/10/03)
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- Pseudophase Approach to Reactivity in Microemulsions: Quantitative Explanation of the Kinetics of the Nitrosation of Amines by Alkyl Nitrides in AOT/Isooctane/Water Microemulsions
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The kinetics of the nitroso group transfer from 2-ethoxyethyl (EEN) and 2-bromoethyl (BEN) nitrit+e to the secondary amines piperazine (PIP), N-methylbenzylamine (NMBA), and morpholine (MOR) in bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane(iC8)/water microemulsions were determined.They are explained quantitatively in terms of a model in which the reagents are distributed among the aqueous, organic, and AOT film surfactant, with the aqueous pseudophase and the surfactant film as the losi of the reaction.
- Garcia-Rio, L.,Leis, J. R.,Mejuto, J. C.
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p. 10981 - 10988
(2007/10/03)
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- Transfer of the Nitroso Group in Water/AOT/Isooctane Microemulsions: Intrinsic and Apparent Reactivity
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The kinetics of the transfer of the nitroso group from N-methyl-N-nitroso-p-toluenesulfonamide to each of seven secondary amines (piperazine, N-methylbenzylamine, piperidine, dimethylamine, morpholine, pyrrolidine, and diisopropylamine) was studied using a wide variety of water/AOT/isooctane microemulsions as reaction media.The diverse kinetic behavior of the various amines can be explained quantitatively on the basis of a single model taking into account the distribution of the amine among the aqueous and isooctane phases and their mutual interface; the reaction itself always takes place at the interface.The relative reactivities of the amines are discussed in comparison with the order observed in water.
- Garcia-Rio, Luis,Leis, J. Ramon,Pena, M. Elena,Iglesias, Emilia
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p. 3437 - 3442
(2007/10/02)
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- Formation of Nitrosamines in Alkaline Conditions: a Kinetic Study of the Nitrosation of Linear and Cyclic Secondary Amines by Nitroalkanes
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A study has been made of the nitrosation of sixteen secondary amines, six alkylamines (dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diisobutylamine) and ten cyclic secondary amines (2-methylaziridine, azetidine, pyrrolidine, piperidine, 2-methylpiperidine, homopiperidine, heptamethyleneimine, piperazine, 1-methylpiperazine and morpholine) by nitropropane and nitrobutane in a strongly basic medium (-> = 0.1 mol dm-3).The nitrites were not formed in situ (i.e. in the actual bulk of the reaction medium) but rather were isolated,purified and used in pure form.The rate equation (i) was found v = k2obs (i).The fitting of the experimental results to the Taft correlation points to a nucleophilic attack on nitrite esters by the amines.Analysis of the log k2/pKa and log k2/Ei(v) correlations indicates orbital control of the reactions studied.These results, together with the fact that the reactivity of the different amines diminishes ostensibly when the values of the 13C-H nuclear spin coupling constant in the series of corresponding cycloalkanes increase, show that the overall hybridization of the nitrogen atom in the cycle changes from sp2 in the triangular nucleophile methylaziridine to sp3 in larger cycles.The results obtained at different temperatures and with water-tetrahydrofuran media, together with a study of isotope effects suggest that these reactions occur through a highly ordered transition state and that the role of solvation should not be overlooked.
- Calle, Emilio,Casado, Julio,Cinos, Jose L.,Mateos, Francisco J. Garcia,Tostado, Manuel
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p. 987 - 991
(2007/10/02)
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