Nitrosamine acyclic

Cyclic nitrosamines are among the most potent and environmentally significant nitrosamine carcinogens. Like the acyclic nitrosamines, metabolism is necessary for their carcinogenicity. Elucidation of the specific metabolic pathways of cyclic nitrosamine activation and detoxification is a challenging problem, and considerable progress has been achieved in recent years. In this chapter, we will review metabolic studies on N-nitrosopyrrolidine (NPYR), N -nitrosonornicotine (NNN), N-nitrosopiperidine (NPIP), N-nitrosohexamethyleneimine (NHEX), N-nitrosomorpholine (NMOR),... 

We became interested in whether or not biological structure-activity relationships could be developed for any of these sets of compounds. Only the acyclic nitrosamines appeared to constitute a sufficiently extensive and well-defined series, and we consequently carried out computerized multiple regression analyses on this group of compounds, using log (I/D50) the dependent variable analogous to RBR (12). 

The relationship described by equation 4 indicates that most of the variation in carcinogenicity within the series of acyclic nitrosamines can be associated with water-hexane partition coefficients and electronic inductive effects of substituents on the a-carbons. 

In summary, it appears that the differences in carcinogenic potency for both cyclic and acyclic N-nitrosodialkylamines are real and systematic, and that the potencies of environmental nitrosamines should be considered in assessing the relative hazards associated with these compounds. In addition, it can be shown that the carcinogenicity of nitrosamines can be associated... 

HPLC determination of acyclic Af-nitrosamines. Both gave acceptable results, but the former gave a much superior resolution of the respective E and Z isomers. 

We examined the thermal decomposition of a number of nitramines in dilute solution and in the melt phase. The nitramines included acyclic dialkyl mononitramines, where the dialkyls were methyl, ethyl, propyl and isopropyl cyclic mononitramines (N-nitro-pipeiidine and N-nitropyrrolidine) and cycle multifunctional nitramines (N-dinitropiperazhe l,3-dinitro-l,3-diazacyclo-pentane l,3-dinitro-l,3-diazacycbhexane RDX and HMX). For all nitramines, the predominant condensed-phase product was the nitrosamine though the amount formed depending on the nitramine and the phase of the thermolysis. The common trigger in the decompositions was N-N02 ho mo lysis, but the fate of the resultant amine radical depended on the phase. In solution the radical was stabilized sufficiently so that it resisted further decomposition and, instead, reacted with NO to form nitrosamine. In vapor or condensed phase, the amine radical underwent further reaction therefore,... 

Reductive splitting of a bond between a nitrogen atom and heteroatom occurs in many compounds of the type X=N-Y, where X may be carbon, oxygen, or nitrogen and Y may be oxygen or nitrogen [229]. This rule thus applies to cyclic and acyclic hydrazines, oximes, /7-amino and /7-hydroxyazobenzenes, triazines in acid solution, and Y-nitrosamines in alkaline solution. 

For the sake of completeness, several components have been included in Table XII-2 because they possess the amine function (-NH2) but are not linked to a carbon atom, for example, ammonia, hydrazine, and hydroxylam-ine. None of them fits the definition of an amide, imide, or lactam. Other components included in Table XII-2 for the sake of completeness are the amino acids with acyclic unsubstituted or substituted amine groups, the acyclic A-nitrosamines, and the A-heterocyclic amines. With the inclusion in Table XII-2 of the various items just mentioned, the number of acyclic amines and their derivatives total 469, with 259 identified in smoke, 316 in tobacco, and 106 in both tobacco and smoke. 

Nitrogen-Containing Components Chapter 11. Nitriles Chapter 12. Acyclic Amines Chapter 13. Amides Chapter 14. Imides Chapter 15. N-Nitrosamines... 

Human Cultured bronchi Comparative metabolism of acyclic and cyclic nitrosamines 178... 

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