Kinetic studies on the formation ofN-nitroso compounds VI. The reactivity of N2O3 as a nitrosating agent

Casado, Julio; Castro, Ana de; Leis, Jaan; López‐Quintela, M. Arturo; Mosquera, Manuel

doi:10.1007/bf01134177

Cited by 42 publications

(34 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7 and Table 2). The enthalpy of activation (Δ H ‡ = 41 ± 2 kJ/mol) and activation energy ( E a = 43 ± 2 kJ/mol) indicate a relatively low activation barrier for the reaction and are consistent with values obtained from other experimental and theoretical examinations of nitrosation of secondary amines 39–41. The negative entropy of activation (Δ S ‡ = −120 ± 10 J/mol·K) is consistent with an associative nitrosation mechanism.…”

Section: Resultssupporting

confidence: 86%

Mechanism of Nitric Oxide Reactivity and Fluorescence Enhancement of the NO-Specific Probe CuFL1

2010

View full text Add to dashboard Cite

The mechanism of the reaction of CuFL1 (FL1 = 2-{2-chloro-6-hydroxy-5-[(2-methylquinolin-8-ylamino)-methyl]-3-oxo-3H-xanthen-9-yl}benzoic acid) with NO to form the N-nitrosated product FL1-NO in buffered aqueous solutions was investigated. The reaction is first order in CuFL1, NO, and hydroxide ion. Rate saturation at high base concentrations is consistent with a mechanism in which the protonation state of the secondary amine of the ligand is important for reactivity. This information provides a rationale for designing faster-reacting probes by lowering the pKa of the secondary amine. Activation parameters for the reaction of CuFL1 with NO indicate an associative mechanism (ΔS‡ = −120 ± 10 J/K·mol) with a modest thermal barrier (ΔH‡ = 41 ± 2 kJ/mol; Ea = 43 ± 2 kJ/mol). Variable pH EPR experiments reveal that, as the secondary amine of CuFL1 is deprotonated, electron density shifts to yield a new spin-active species having electron density localized on the deprotonated amine nitrogen atom. This result suggests that FL1-NO formation occurs when NO attacks the deprotonated secondary amine of the coordinated ligand, followed by inner-sphere electron transfer to Cu(II) to form Cu(I) and release of FL1-NO from the metal.

show abstract

Section: Resultssupporting

confidence: 86%

Mechanism of Nitric Oxide Reactivity and Fluorescence Enhancement of the NO-Specific Probe CuFL1

2010

View full text Add to dashboard Cite

show abstract

“…The unvarying order of magnitude 10 8 M -1 s -1 found for the true rate coefficient for the N-nitrosation step when one is working with many secondary amines under conditions in which the effective nitrosating agent is thought to be dinitrogen trioxide indicates that the attack of the N 2 O 3 upon free amines must be diffusion-controlled (Casado et al, 1983(Casado et al, , 1994. This permits us to propose the following mechanism of reaction: Comparison of the experimental (eq 2) and theoretical (eq 3) rate equations affords the values of R and and hence that of k, the attack constant of N 2 O 3 on each substrate, since (Markovits et al, 1981).…”

Section: Resultsmentioning

confidence: 97%

Inhibition of Nitrosation by Steric Hindrance

González‐Mancebo

Calle

García-Santos

et al. 1997

J. Agric. Food Chem.

Self Cite

View full text Add to dashboard Cite

The nitrosation of piperidine, 2-methylpiperidine, 4-methylpiperidine, 2,6-dimethylpiperidine, and 2-ethylpiperidine in acid medium was studied. Kinetic monitoring of the reactions was accomplished by spectrophotometric analysis of the nitrosamine formed at λ ) 249 nm. In each case, the value of the rate constant of the determining step R 2 NH + N 2 O 3 f R 2 NNO + HNO 2 was calculated, observing the following sequence of reactivities: piperidine ≈ 4-methylpiperidine > 2-methylpiperidine ≈ 2-ethylpiperidine > 2,6-dimethylpiperidine. In the case of 2,6-dimethylpiperidine, no nitrosation was observed. The results are interpreted in terms of the steric hindrance of the alkyl groups to attack of the secondary amine group by dinitrogen trioxide. The results open the possibility of blocking the undesirable mechanisms of formation of N-nitroso compounds.

show abstract

“…Table 3 displays values of the rate constants for the reaction between these nitrosating agents and different substrates [78][79][80][81][82][83][84][85]. Table 3 displays values of the rate constants for the reaction between these nitrosating agents and different substrates [78][79][80][81][82][83][84][85].…”

Section: Rate Equations In Nitrosationmentioning

confidence: 99%

Cyclodextrins in Nitrosation Chemistry: New Insights of the NO-Transfer Processes

Iglesias

2005

MROC

View full text Add to dashboard Cite

The chemistry of nitroso compounds has received considerable attention from several directions in recent years. This review will focus on describing the practical aspects, and current and potential applications of cyclodextrins in mechanistic studies of NO-transfer processes. The first section describes some physicochemical aspects of aqueous cyclodextrin solutions that are of crucial importance in relation to mechanistic studies. The next section analyses all types of information that can be obtained from different nitrosation reaction patterns either in acid or basic media, by paying special attention to the nitrosatable substrates and nitrosating agents. Relevant aspects concerning the biological activity of nitroso compounds is also included. The last section covers a detailed analysis of the effects of cyclodextrins on reactions undergone by nitroso compounds, such as hydrolysis or NO-transfer, as well as on reactions that produce nitroso compounds.

show abstract

Kinetic studies on the formation ofN-nitroso compounds VI. The reactivity of N2O3 as a nitrosating agent

Cited by 42 publications

References 17 publications

Mechanism of Nitric Oxide Reactivity and Fluorescence Enhancement of the NO-Specific Probe CuFL1

Mechanism of Nitric Oxide Reactivity and Fluorescence Enhancement of the NO-Specific Probe CuFL1

Inhibition of Nitrosation by Steric Hindrance

Cyclodextrins in Nitrosation Chemistry: New Insights of the NO-Transfer Processes

Contact Info

Product

Resources

About