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Versatile new reagent for nitrosation under mild conditions
Here we report a new chemical reagent for transnitrosation under mild experimental conditions. This new reagent is stable to air and moisture across a broad range of temperatures and is effective for transnitrosation in multiple solvents. Compared with traditional nitrosation methods, our reagent shows high functional group tolerance for substrates that are susceptible to oxidation or reversible transnitrosation. Several challenging nitroso compounds are accessed here for the first time, including 15N isotopologues. X-ray data confirm that two rotational isomers of the reagent are configurationally stable at room temperature, although only one isomer is effective for transnitrosation. Computational analysis describes the energetics of rotamer interconversion, including interesting geometry-dependent hybridization effects.
Galloway, Jordan D.,Sarabia, Cristian,Fettinger, James C.,Hratchian, Hrant P.,Baxter, Ryan D.
supporting information
p. 3253 - 3258
(2021/05/06)

The Use of Potassium/Sodium Nitrite as a Nitrosating Agent in the Electrooxidative N-Nitrosation of Secondary Amines
We report herein on the electrochemical N-nitrosation of secondary amines using widely available sodium/potassium nitrite as a nitrosating agent. This approach not only eliminates the need for using a combination of sodium/potassium and a strong acid but also has good functional group tolerance. The reaction is compatible with the late-stage modification of pharmaceutical compounds and could be conducted in gram scale with a high reaction efficiency. Preliminary mechanistic studies indicate that the N-nitrosation occurs via the anodic oxidation of KNO2 into an NO2 radical which is then transformed into an NO+ cation.
Chen, Zuxing,Gao, Meng,Lu, Cuifen,Ma, Chao,Ruan, Mengyao,Wang, Feiyi,Wang, Ying,Yang, Guichun,You, Shiqi
supporting information
p. 3289 - 3293
(2021/07/02)

Visible-Light-Induced Photoaddition of N-Nitrosoalkylamines to Alkenes: One-Pot Tandem Approach to 1,2-Diamination of Alkenes from Secondary Amines
The generation of aminium radical cation species from N-nitrosoamines is disclosed for the first time through visible-light excitation at 453 nm. The developed visible-light-promoted photoaddition reaction of N-nitrosoamines to alkenes was combined with the o-NQ-catalyzed aerobic oxidation protocol of amines to telescope the direct handling of harmful N-nitroso compounds, where the desired α-amino oxime derivatives were obtained in a one-pot tandem N-nitrosation and photoaddition sequence.
Patil, Dilip V.,Si, Tengda,Kim, Hun Young,Oh, Kyungsoo
supporting information
p. 3105 - 3109
(2021/05/05)

Electrochemical Nonacidic N-Nitrosation/N-Nitration of Secondary Amines through a Biradical Coupling Reaction
An acid-free N-nitrosation/nitration of the N?H bonds in secondary amines with Fe(NO3)3 ? 9H2O as the nitroso/nitro source through an electrocatalyzed radical coupling reaction was developed. Cyclic aliphatic amines and N-heteroaromatic compounds were N-nitrosated and N-nitrated, respectively, under mild conditions. Control and competition experiments, as well as kinetic studies, demonstrate that N-nitrosation and N-nitration involve two different radical reaction pathways involving N+ and N. radicals. Moreover, the electrocatalysis method enables the preferential activation of the N?H bond over the electrode and thus provides high selectivity for specific N atoms. Finally, this strategy exhibits a broad scope and provides a green and straightforward approach to generate useful N-nitroso/nitro compounds in good yields. (Figure presented.).
Zhao, Ji-Ping,Ding, Lu-jia,Wang, Peng-Cheng,Liu, Ying,Huang, Min-Jun,Zhou, Xin-Li,Lu, Ming
supporting information
p. 5036 - 5043
(2020/07/13)

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)

Synthesis and properties of 2-hydroxyethyl derivatives of methylene-bis(1-oxy-3, 3-dialkyl-1-triazene 2-oxides)
Synthetic approach to 2-hydroxyethyl derivatives of methylene-bis(1-oxy-3, 3-dialkyl-1triazene 2-oxides), promising NO donors, which can release NO in living organisms was developed. Some transformations of the hydroxyethyl moiety of the synthesized compounds were studied.
Smirnov,Nikitin,Gordeev,Pokhvisneva,Ternikova,Luk’yanov
p. 2706 - 2711
(2016/10/03)

Facile N-nitrosation of secondary amines using poly(N,N'-dibromo-Nethylene- benzene-1,3-disulfonamide) and N,N,N′,N′-tetrabromobenzene-1,3- disulfonamide/NaNO2 under mild conditions
In this research project, a combination of poly(N,N′-dibromo-N- ethylene-benzene-1,3-disulfonamide) [PBBS] and/or (N,N,N′,N′- tetrabromobenzene-1,3-disulfonamide) [TBBDA] with sodium nitrite in the presence of wet SiO2 (50% w/w) was used as an efficient nitrosating agent for the conversion of secondary amines to their corresponding nitroso compounds. N-Nitrosation reaction has been performed in dichloromethane at room temperature under mild and heterogeneous conditions. The reaction is operationally simple and corresponding products were achieved in good to excellent yields.
Ghorbani-Vaghei, Ramin,Shiri, Lotfi,Ghorbani-Choghamarani, Arash
p. 204 - 208
(2013/07/26)

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)

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)

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)

Process for Synthesizing Nitramine Compounds
There is disclosed a process for synthesizing nitrosamine compounds. Specifically, there is disclosed a process for synthesizing N-nitropyrrolidine.
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(2009/12/05)

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)

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)

Alumina-methanesulfonic acid (AMA)/NaNO2 as an efficient procedure for the chemoselectivite N-nitrosation of secondary amines
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
p. 2311 - 2319
(2007/10/03)

The reaction of peroxynitrite with morpholine (secondary amines) revisited: The overlooked hydroxylamine formation
The reaction of peroxynitrite/peroxynitrous acid with morpholine as a model compound for secondary amines is reinvestigated in the absence and presence of carbon dioxide. The concentration- and pH-dependent formation of N-nitrosomorpholine and N-nitromorpholine as reported in three previous papers ([25] [26] [14]) is basically confirmed. However, 13C-NMR spectroscopic product analysis shows that, in the absence of CO2, N-hydroxymorpholine is, at pH≥7, the major product of this reaction, even under anaerobic conditions. The formation of N-hydroxymorpholine has been overlooked in the three cited papers. Additional (ring-opened) oxidation products of morpholine are also detected. The data account for radical pathways for the formation of these products via intermediate morpholine-derived aminyl and α-aminoalkyl radicals. This is further supported by EPR-spectrometric detection of morpholine-derived nitroxide radicals, i.e., morpholin-4-yloxy radicals. N-Nitrosomorpholine, however, is very likely formed by electrophilic attack of peroxynitrite-derived N2O4. 15N-CIDNP Experiments establish that, in the presence of CO2, N-nitro- and C-nitromorpholine are generated by radical recombination. The present results are in full accord with a fractional (28±2% ) homolytic decay of peroxynitrite/peroxynitrous acid with release of free hydroxyl and nitrogen dioxide radicals.
Kirsch, Michael,Korth, Hans-Gert,Wensing, Angela,Lehnig, Manfred,Sustmann, Reiner,De Groot, Herbert
p. 2399 - 2424
(2007/10/03)

Nitrosation of Amines in Non-Aqueous Solvents - Difference between N-N=O and O-N=O Nitroso Donors
A kinetic study has been carried out on nitroso group transfer from substituted N-methyl-N-nitroso-benzenesulfonamides to different secondary amines: pyrrolidine, piperidine, N-methylpiperazine, and morpholine in cyclohexane. The observed pseudo-first-order rate constant kobs shows a linear and quadratic dependency on the amine concentration with the existence of a primary kinetic isotope effect. Experiments carried out at different temperatures show Arrhenius-type behavior. Addition of isopropylamine (iPrNH2) to the reaction medium produces an increase in k obs. In the presence of a high iPrNH2 concentrations the influence of secondary amine concentration on kobs shows the disappearance of the quadratic dependency of kobs on the secondary amine. These results would be compatible with an addition-elimination mechanism, similar to that observed for the aminolysis of the alkyl nitrites in apolar solvents. The observed behavior in the presence of 18-crown-6 is very different, however. Addition of crown ether catalyses the reaction of aminolysis of alkyl nitrites insofar as it does not alter the rate of the nitroso group transfer from N-nitrososulfonamides. This behavior has been interpreted in terms of a concerted reaction mechanism through cyclical transition states, with four or six centers, involving one or two molecules of secondary amine. Addition of iPrNH2 to the reaction medium causes the appearance of a third reaction path, which emerges through a mixed transition state formed by a molecule of a secondary amine and a molecule of isopropylamine. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Garcia-Rio, Luis,Leis, Jose R.,Moreira, Jose A.,Serantes, David
p. 614 - 622
(2007/10/03)

Amidine Nitrosation
The acidic nitrosation chemistry of nine acyclic secondary and tertiary amidines (Ph-N=C(R1)-NR2R3; R1 = H, CH3, Ph; R2, R3 = H, Ph or (CH 3)2 or C(CH2)4) and several N-acylamidines was investigated. The principal nitrosation products were amides derived from the amino moiety and compounds derived from the benzenediazonium ion, which was independently trapped for quantitation in several cases. Tertiary amidines also produce nitrosamines in minor, but significant, yields. The benzamidines did not react, and the N-acylamidines hydrolyzed much more rapidly than they nitrosated. The data support the hypothesis that the reaction occurs by nitrosation on the imino nitrogen, followed by the addition of H 2O to give a tetrahedral intermediate (α-hydroxynitrosamine) for which the main decomposition pathway generates an amide and a diazonium ion. In the case of the pyrrolidine-derived amidines, about 25% of the decomposition results in cleavage of the amine moiety, which nitrosates to give N-nitrosopyrrolidine. Pseudo-first-order rate constants for amidine nitrosation in aqueous acetic acid with excess nitrite at 25 °C ranged from (3 to 106) × 10-5 s-1, while the amidine basicity ranged over 5 pKa units. Rate constants corrected for amidine basicity showed the pyrrolidine derived amidines to be most reactive. The lack of benzamidine nitrosative reactivity is attributed to a very slow rate of H2O additon to the N-nitrosoamidinium ion and reversible nitrosation.
Loeppky, Richard N.,Yu, Hongbin
p. 3015 - 3024
(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)

Trichloroisocyanuric acid/NaNo2 as a novel heterogeneous system for the N-nitrosation of N,N-dialkylamines under mild conditions
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
p. 1002 - 1004
(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)

Differences in the activity of neutral and ionized β-cyclodextrin on the nitrosation of amines by phenylpropyl nitrites
The influence of β-cyclodextrin (β-CD) on the base-catalyzed hydrolysis reaction of 1-phenyl-1-propyl, 2-phenyl-1propyl and 3-phenyl-1-propyl nitrites and on the nitrosation of pyrrolidine, piperidine and N-methylcyclohexylamine by the aforementioned alkyl nitrites (RONO) is studied in aqueous buffers of the amines and in an alkaline medium with [OH-] = 0.20 M. The hydrolysis reaction is catalyzed by the presence of β-CD owing to the formation of reactive 1:1 inclusion complexes between the alkyl nitrite and the ionized β-CD; the addition of potential inhibitors, such as dodecyltrimethylammonium bromide monomers, accelerates the reaction even more. The effect is quite significant in the case of 1-phenyl-1-propyl nitrite and is viewed as a case of allostery. In the presence of neutral β-CD, the nitrosation by 1-phenyl-1-propyl nitrite, either of pyrrolidine or piperidine, is inhibited by β-CD addition; however, the nitrosation reaction of piperidine by 2-phenyl-1-propyl nitrite is catalyzed (passing through a maximum) by β-CD, whereas the nitrosation of pyrrolidine promoted by 3-phenyl-1-propyl nitrite exhibits practically no change upon β-CD addition. In alkaline media (containing ionized β-CD) the nitrosation of pyrrolidine by 1-phenyl-1-propyl nitrite is inhibited by the presence of β-CD; in contrast, the nitrosation of both piperidine and N-methylcyclohexylamine is catalyzed in all cases, but the degree of catalysis depends not only on the alkyl nitrite structure, but also on the type and concentration of the amine. Kinetic results are quantitatively interpreted on the basis of the proposed reaction mechanism in each case, and the kinetic rate constants of the different steps are determined. Comparison of the results obtained in aqueous alkaline media and in aqueous buffers of the amines themselves allows us to establish important characteristics of the transition state of the reaction.
Iglesias
p. 1025 - 1035
(2007/10/03)

Formation of N-nitrosamines and N-nitramines by the reaction of secondary amines peroxynitrite and other reactive nitrogen species: Comparison with nitrotyrosine formation
Reactive nitrogen species, including nitrogen oxides (N2O3 and N2O4), peroxynitrite (ONOO-), and nitryl chloride (NO2Cl), have been implicated as causes of inflammation and cancer. We studied reactions of secondary amines with peroxynitrite and found that both N-nitrosamines and N- nitramines were formed. Morpholine was more easily nitrosated by peroxynitrite at alkaline pH than at neutral pH, whereas its nitration by peroxynitrite was optimal at pH 8.5. The yield of nitrosomorpholine in this reaction was 3 times higher than that of nitromorpholine at alkaline pH, whereas 2 times more nitromorpholine than nitrosomorpholine was formed at pH 2N·), which react with nitric oxide (·NO) or nitrogen dioxide (·NO2) to yield nitroso and nitro secondary amines, respectively. Reaction of morpholine with NO· and superoxide anion (O2·-), which were concomitantly produced from spermine NONOate and by the xanthine oxidase systems, respectively, also yielded nitromorpholine, but its yield was 2·- inhibited its formation. Reactions of morpholine with nitrite plus HOCl or nitrite plus H2O2, with or without addition of myeloperoxidase or horseradish peroxidase, also yielded nitration and nitrosation products, in yields that depended on the reactants. Tyrosine was nitrated easily by synthetic peroxynitrite, by NaNO2 plus H2O2 with myeloperoxidase, and by NaNO2 plus H2O2 under acidic conditions. Nitrated secondary amines, e.g., N-nitroproline, could be identified as specific markers for endogenous nitration mediated by reactive nitrogen species.
Masuda, Mitsuharu,Mower, Howard F.,Pignatelli, Brigitte,Celan, Irena,Friesen, Marlin D.,Nishino, Hoyoku,Ohshima, Hiroshi
p. 301 - 308
(2007/10/03)

Reactivity of nitrogen nucleophiles towards S-nitrosopenicillamine
We report the results of a kinetic study of the reactions of a number of nitrogen nucleophiles with the nitrosothiol S-nitrosopenicillamine (SPEN). The range of nucleophiles includes primary, secondary and tertiary aliphatic amines, together with hydrazine, hydroxylamine, azide ion, ammonia, semicarbazide, thiomorpholine and S-methylcysteine. Secondary amines form N-nitrosamines quantitatively. As expected, reaction occurs via the free base forms of the nucleophiles and consequently most of the reactions take place readily only at relatively high pH. Experiments were carried out with [nucleophile] ? [RSNO], and for many reactions, plots of the first order rate constant vs. [nucleophile] were linear. For ammonia and the primary amines, however, this plot tended to level off at high [nucleophile] and an explanation is offered involving the reversible formation of an inactive RSNO-amine complex, for which there is spectral evidence, in parallel with the main reaction. For the secondary amines there is a reasonably good Broensted plot with a β value of ～0.2. The much greater reactivities of S-methylcysteine and thiomorpholine, compared to those of primary amines and morpholine respectively are consistent with initial attack at the sulfur atom, followed by an internal rearrangement. Over the whole range of nucleophiles studied there is a reasonable correlation with the Ritchie N+ parameter, and not with the Pearson n scale. Comparisons are made with the corresponding reactions of alkyl nitrites and N-methyl-N-nitrosotoluene-p-sulfonamide (MNTS).
Munro, Andrew P.,Williams, D. Lyn H.
p. 1989 - 1993
(2007/10/03)

The reaction of pentacyanonitrosylferrate(II) with primary amines as a source of stabilized aliphatic diazonium ions: A new route to secondary amines
Pentacyanonitrosylferrate(II), 1, reacts with n-butylamine to produce di-n-butylamine in high yields (81-95%). The absence of rearranged products indicates that the initially produced diazonium ion is stabilized by coordination to the metal. Benzylamine and 1,4-diaminobutane react with 1 to produce dibenzylamine and piperidine, respectively.
Doctorovich, Fabio,Trapani, Cecilia
p. 4635 - 4638
(2007/10/03)

Cyclodextrins as enzyme models in nitrosation and in acid-base- catalyzed reactions of alkyl nitrites
The widely studied cyclodextrin-mediated reactions of esters but not those of alkyl nitrites, together with the marked differences between the chemistry of esters and alkyl nitrites, prompted us to investigate the influence of β-cyclodextrin (β-CD) on the reactions of alkyl nitrites. Due to the particular characteristics of alkyl nitrite reactions, the system β- cyclodextrin-alkyl nitrites allows us to explore cyclodextrin's behavior under several experimental conditions, contrary to the case of esters. Therefore, general acid-base-catalyzed hydrolysis and nitrosation of amines by alkyl nitrites are studied. Alkyl nitrites of a particular structure have been chosen to clearly evidence the mimicry of enzyme catalysis by β-CD. Addition of β-CD strongly inhibits the acid hydrolysis of alkyl nitrites (a very fast reaction in water), except in the case of ethoxyethyl nitrite, where no effect is detected. The retardation of the reaction is attributed to a separation of the reagents: β-CD and alkyl nitrites form host-guest 1:1 inclusion complexes, but simple cations, such as H3O+ in the present case, did not prove to include into the β-CD cavity. In fact, at constant β-CD concentrations, addition of dodecyltrimethylammonium bromide monomers (DTABr), which strongly compete with alkyl nitrites for the hydrophobic β- CD cavity and, thus, expel the alkyl nitrites, catalyzes the reaction. On the contrary, in alkaline medium, when a secondary hydroxy group of β-CD is ionized, addition of β-CD to the reaction medium strongly catalyzes the basic hydrolysis of alkyl nitrites (an extremely slow reaction in water). The degree of catalysis depends on the alkyl nitrite structure, varying from a factor higher than 100 in the case of 3-phenyl-1-propyl nitrite, to 0 (no reaction is observed) in the case of 2-phenyl-2-propyl nitrite. The effective molarities calculated for the catalysis evidence a base-catalyzed mechanism for the reaction. The strong catalysis observed with 1-phenyl-1-propyl nitrite upon the addition of DTABr is indicative of an example of allosteric activation. Finally, the nitrosation of pyrrolidine, piperidine, and cyclohexylamine by ethoxyethyl nitrite is slightly catalyzed by the presence of β-cyclodextrin. The degree of the observed catalysis depends on both the amine concentration and the structure.
Iglesias, Emilia
p. 13057 - 13069
(2007/10/03)

Nitrosation of Amines in Nonaqueous Solvents, 1. Evidence of a Stepwise Mechanism
We studied the nitrosation of piperidine, morpholine, pyrrolidine, N-methylpiperazine, N,N′-dimethylethylenediamine and diethylamine by 2-bromoethyl nitrite, 2,2-dichloroethyl nitrite, 2,2,2-trichloroethyl nitrite, or N-methyl-N-nitroso-p-toluenesulfonamide (MNTS) in cyclohexane, isooctane, dichloromethane, 1,4-dioxane, or tetrahydrofuran. The dependence of the first-order pseudoconstant k0 on the amine concentration (always in excess) was sigmoid for nitrosation by alkyl nitrites and linear or quadratic for nitrosation by MNTS. The effects on k0 of isotopic substitution, temperature, and base catalysis by a less reactive amine were also determined. The experimental data are in keeping with a reaction mechanism involving a zwitterionic tetrahedral intermediate T± analogous to intermediates postulated for the aminolysis of carboxylic esters in similar solvents: according to this mechanism, T± is formed either directly from the amine and nitrosating agent (in the case of MNTS) or indirectly via a hydrogen-bonded complex between the amine and nitrosating agent (in the case of alkyl nitrites) and decomposes either spontaneously or with the catalytic assistance of a second amine molecule. For alkyl nitrites, the rate-controlling step is the formation of T± at high amine concentrations and its decomposition at low amine concentrations; for MNTS, the rate-controlling step is the formation of T± in more polar solvents and its decomposition in less polar solvents. An alternative mechanism, involving the formation of T± from both monomers and dimers of the amine, is ruled out.
Garcia Rio,Leis,Iglesias
p. 4701 - 4711
(2007/10/03)

Nitrosation of Amines in Nonaqueous Solvents. 2. Solvent-Induced Mechanistic Changes
We studied the nitrosation of amines (pyrrolidine, piperidine, diethylamine, N-methylpiperazine, N,N′-dimethylethylenediamine, and morpholine) by alkyl nitrites (2-bromoethyl nitrite or 2,2- dichloroethyl nitrite) or by N-methyl-N-nitroso-p-toluenesulfonamide (MNTS) in the solvents chloroform, acetonitrile, and dimethyl sulfoxide (DMSO). The mechanism of nitrosation by alkyl nitrites depends on the solvent: in chloroform, all the results were in keeping with formation of a hydrogen-bonded complex between the amine and alkyl nitrite being followed by rate-controlling formation of a tetrahedral intermediate T± that rapidly decomposes to afford the final products; in acetonitrile, a situation intermediate between those obtaining in chloroform and cyclohexane results in the [amine] dependence of the first-order pseudoconstant k0 being qualitatively influenced by temperature and by the identities of both the amine and the alkyl nitrite; in DMSO, the results suggest a mechanism close to the mechanism acting in water. For nitrosation by MNTS, k0 depended linearly on [amine] in all three solvents. The Grunwald-Winstein coefficients correlating the rate constants k for nitrosation by MNTS in the chloroform, acetonitrile, DMSO, dioxane, dichloromethane, and water were l = 0.12 and m = 0.29. Correlation with the Kamlet-Abboud-Taft equation confirmed that k depends largely on the dipolarity of the solvent and, to a lesser extent, its capacity for hydrogen bonding.
Garcia-Rio,Leis,Iglesias
p. 4712 - 4720
(2007/10/03)

Mechanisms of Nitramine Thermolysis
The thermal decomposition of a number of nitramines was studied in dilute solution and in the melt.The nitramines included acyclic mononitramines , cyclic mononitramines , cyclic dinitramines , and 1,3,5-trinitro-1,3,5-triazocyclohexane (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), hexanitrohexaazaisowurtzitane (HNIW), and 1,3,3-trinitroazetidine (TNAZ).For the acyclic and cyclic mono- and dinitramines, the corresponding nitrosamines were the only or major condensed-phase product.Kinetics and activation parameters were determined for the thermolysis of dilute solutions (0.01-1.0 wtpercent) over the range 200-300 deg C.The thermolyses were found to be first-order with the rate constants unaffected by the use of deuterated solvent.As the nitramines became more complex than dimethylnitramine (DMN), the rate of decomposition increased and the product distribution became more complex.As the length of the aliphatic chain increased (DMN DEN DPN), the rate of thermolysis increased, yet nitrosamine remained the only observed condensed-phase product.When a secondary carbon was attached to the N-nitramine (DIPN) rather than the primary (DPN), the rate of decomposition increased and a new condensed-phase product was observed.Among the cyclic nitramines, the rate of decomposition increased as the number of NNO2 groups increased (NPIP pDNP; NPyr DNI; mDMP RDX).The position of the nitramine groups affected the decomposition: meta NNO2 groups (mDNP) decomposed faster than para (pDNP).Ring strain decreased stability: mDNP DNI; HMX RDX.In complex nitramines, the increase in decomposition rate, the appearance of new products, and the change in the relative importance of nitrosamine and of N2 and N2O are attributed to new decomposition routes available to them.However, since complex nitramines (e.g.RDX) maintain first-order kinetics and since most have activation energies in the range of 40-50 kcal/mol, it is belived that the triggering mechanism remains N-NO2 homolysis.Intramolecular hydrogen transfer is also considered an important mode of nitramine decomposition.
Oxley, J. C.,Kooh, A. B.,Szekeres, R.,Zheng, W.
p. 7004 - 7008
(2007/10/02)

Transfer of the Nitroso Group in Water/AOT/Isooctane Microemulsions: Intrinsic and Apparent Reactivity
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
p. 3437 - 3442
(2007/10/02)

Reactivity of Nucleophilic Nitrogen Compounds towards the Nitroso Group
We discuss the reactivity of 43 nucleophilic nitrogen compounds towards the nitroso group of N-methyl-N-nitrosotoluene-p-sulfonamide (MNTS), and in some cases with alkyl nitrites.The series of nucleophiles considered is structurally very varied, includes members exhibiting the alpha effect, and covers 8 pKa units and a range of reactivities of almost five orders of magnitude.The values of solvent isotope effects and activation parameters have been measured and throw light on the structure of the transition states involved.Reactivities do not correlate well with thebasicity of the nucleophile, largely owing to the behaviour of primary amines, ammonia and nucleophiles with an alpha effect.Application of the curve crossing model suggests a relationship with vertical ionization potentials.The relationship with Ritchie's N+ scale is discussed, and interesting correlations with the reactivities of the same nucleophiles in various other chemical processes are noted.
Garcia-Rio, Luis,Iglesias, Emilia,Leis, J. Ramon,Pena, M. Elena,Rios, Ana
p. 29 - 37
(2007/10/02)

Formation of Nitrosamines in Alkaline Conditions: a Kinetic Study of the Nitrosation of Linear and Cyclic Secondary Amines by Nitroalkanes
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
p. 987 - 991
(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)

Nitrosamines, N-nitrosoamides, and diazonium ions from tri-N-substituted amidines
N'-Substituted pyrrolidyl amidines react with HNO2 at 37°C. to give N-nitrosopyrrolidine, N-nitrosoamides, and diazonium derived products.
Loeppky,Yu
p. 3263 - 3266
(2007/10/02)

Facile Formation of N-Nitrosamines from Bromonitromethane and Secondary Amines
Bromonitromethane readily converts secondary amines to N-nitrosamines in aqueous and organic solvents at room temperature via reaction of an iminium ion intermediate with nitrite ion.
Challis, Brian C.,Yousaf, Taher I.
p. 1598 - 1599
(2007/10/02)

Reactions of trifluoroamine oxide: A route to acyclic and cyclic fluoroamines and N-nitrosoamines
Acyclic secondary fluoroamines and N-nitrosoamines R2NF and R2NNO (R = CH3, C2H5, n-C3H7, i-C3H7, n-C4H9, i-C4H9, c-C6H11) and saturated nonaromatic heterocyclic fluoroamines and N-nitrosoamines R NF and R NNO [R = c-C4H8, c-C5H10, 2,6-(CH3)2-c-C5H8, 2,2,6,6-(CH3)4-c-C5H6] were prepared by reacting trifluoroamine oxide (NF3O) with the respective amine at ≤0 °C in a 1:2 molar ratio. The amine hydrofluoride salts are also formed. Trifluoroamine oxide is a very effective fluorinating and nitrosating reagent and provides an excellent route to >NF- and >NNO-containing compounds. With PF5, 2,2,6,6-(CH3)4-c-C5H6NFgave [CH2CH2CH2C(CH3)2N +=C(CH3)2]PF6-.
Gupta, Om Dutt,Kirchmeier, Robert L.,Shreeve, Jean'ne M.
p. 2383 - 2386
(2007/10/02)

Structure-reactivity correlations in nitrosation reactions of secondary amines by alkyl nitrites in basic media
A study was conducted on the influence of the basic character of different secondary amines on the rate of their nitrosation reactions by propyl and 2-hydroxyethyl nitrites in basic medium (pH = 9-12).For the series of the five structurally similar amines studied (morpholine, piperazine, N-methylpiperazine, piperidine, and pyrrolidine) an excellent linear correlation was observed between the values of the logarithm of the second order rate constant - corresponding to the attack of the alkyl nitrites on the unprotonated amines - and the pKa of these amines.These results, together with the scattering of linearity when including non structurally similar substrates, confirm that the reactions studied are mainly orbital-controlled and have permitted us a rough estimation of the vertical Ionization Potentials, vIP, of piperazine, N-methylpiperazine and morpholine.The kinetic study of nitrosation reaction of N-methylaniline has led to results from which, when compared with those obtained referring to the five above-mentioned substrates, it is possible to infer again that the reactivity of the nitrosatable substrates studied does not depend exclusively on their pKa.
Casado, Julio,Castro, Albino,Lopez-Quintela, M. Arturo,Lorenzo-Barral, M. Francisco
p. 401 - 404
(2007/10/02)

Inhibition of Nitrosamine Formation by Nondialyzable Melanoidins
The degradation of nitrite and the inhibition towards formation of carcinogenic nitrosamines by melanoidins produced from the glucose-glycine system were investigated at various conditions.The degradation of nitrite was highest at pH 1.2 (29percent), when the ratio of melanoidins to nitrite was 1:3.The inhibition towards formation of nitrosamines by melanoidins had the same tendency as the degradation of nitrite, the inhibition also being highest at pH 1.2 (99percent).In addition, melanoidins after nitrite treatment exhibited a little higher mutagenicity and much stronger desmutagenicity than those of the original melanoidins.The change of the structure of melanoidins after treating with nitrite was also investigated by HPLC and CP-MAS NMR.
Kato, Hiromichi,Lee, In Eui,Chuyen, Nguyen Van,Kim, Seon Bong,Hayase, Fumitaka
p. 1333 - 1338
(2007/10/02)

Reactivite du nitrile de sodium I. Action sur les sels d'iminium
1H and natural abundace 15N NMR spectroscopy has been used to investigate the effect of pH on the reaction of sodium nitrite with iminium salts: three competitive pathways have been detected.In acidic medium, the first step is the hydrolysis of the iminium salts giving amide and amine; the latter reacts with sodium nitrite and nitrosamine is obtained.In basic conditions, the amine is stable and the nucleophilic attack of nitrite ion competes with the two possible hydrolysis reactions.In a non-aqueous medium, simultaneous detection of nitrosamine, amide and methyl nitrite is consistent with an intermediate such as an α amino nitrite ester which may decompose along two different pathways.
Gouesnard, Jean-Paul,Dorie, Jean
p. 132 - 136
(2007/10/02)

Nitrosamines from Tertiary Amines and Dinitrogen Tetraoxide
A preparative nitrosolysis of aliphatic acyclic and cyclic tertiary monoamines to nitrosoamines was brought about by treatment with dinitrogen tetraoxide in carbon tetrachloride at 0-40 deg C.Dealkylation was restricted, where applicable, to demethylation.Competitive oxidation to an amide was observed in the formation of dibutylformamide from tributylamine.Diamine dinitrate salts, without nitrosamine formation, were obtained from 1,4-dimethylpiperazine and 1,4-diazabicyclo-octane; however, each dinitrate salt thermolysed at 180-200 deg C to give a small amount of 1,4-dinitrosopiperazine.In acetic anhydride dinitrogen tetraoxide converted amines less efficiently, gave lower yield of nitrosoamines, was less selective in dealkylation, and introduced the formation of by-products.
Boyer, Joseph H.,Pillai, T. Perumal
p. 1661 - 1664
(2007/10/02)

Nitrosamines and nitramines from tertiary amines
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Boyer,Pillai,Ramakrishnan
p. 677 - 677
(2007/10/02)

Precursors to Nitrosopyrrolidine and Nitrosopiperidine in Black Pepper Treated with Nitrous Acid
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Nakamura, Masamichi,Katoh, Kuni,Kawabata, Toshiharu
p. 1257 - 1260
(2007/10/02)