15216-10-1Relevant articles and documents
Structural features of aliphatic N-nitrosamines of 7-azabicyclo[2.2.1]heptanes that facilitate N-NO bond cleavage
Ohwada,Miura,Tanaka,Sakamoto,Yamaguchi,Ikeda,Inagaki
, p. 10164 - 10172 (2007/10/03)
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.
Formation of Nitrosamines in Alkaline Conditions: a Kinetic Study of the Nitrosation of Linear and Cyclic Secondary Amines by Nitroalkanes
Calle, Emilio,Casado, Julio,Cinos, Jose L.,Mateos, Francisco J. Garcia,Tostado, Manuel
, p. 987 - 991 (2007/10/02)
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.
WEAKENING OF AMIDE CONJUGATION WITH A NITROGEN ATOM INCLUDED IN A FOUR-MEMBERED RING
Alekperov, R. K.,Leshchinskaya, V. P.,Nosova, V. S.,Chervin, I. I.,Kostyanovskii, R. G.
, p. 749 - 751 (2007/10/02)
The barriers to amide rotation about the N-N bond in 1-nitrosoazetidine, dimethylnitrosamine, 1-formylazetidine, 1,1'-carbonylbisazetidine, 1-dimethylcarbamoylazetidine, and dimethylformamide were measured by dynamic NMR spectroscopy. 1,1'-Carbonylbisazetidine and 1-dimethylcarbamoylazetidine, the structures of which were confirmed by data from the PMR and 13C NMR spectra, were obtained.
