Nitrosamide group

It was found that the initial rate of nitrosamide group accumulation is proportional to [NO2] , where n 2. 

As well as in PCA, the interaction of NO2 with PVP leads to UV bands characteristic of the nitrosamide group [20]. The formation of these groups in PVP is associated with splitting of the side-chain cyclic fragments from the main chain ... 

A compound that has more than two mutagenically active groups is mentioned in two or more places. For instance, MMC is cited in two places, one in the aziridine group (1) and the other in the nitrosamide group (3). 

The class of Il-nitroso compounds (l e , nitrosamines and nitrosamides) is currently considered a unique group that includes members with remarkable carcinogenic properties. Because of their potency and almost ubiquitous presence in... 

Nitrosamines, which are the amides of nitrous acid, are more stable and are derived from secondary amines with nitrous acid. iV-nitrosamides are substances which have a carbonyl group attached to a nitrogen-bearing NO group, e.g. iV-nitrosamides, iV-nitrosocarbamates and /V-nitrosoLireas see Figure 10. 

Generally, nitrosamides I undergo irreversible thermal rearrangements (at temperatures ranging from ambient to ca.lOO ) to diazo esters III which themselves decompose even faster under these conditions to give the carboxylic esters or acids and the olefins derived from the R group (1,2). The stability of nitrosamides and the final products from III are very much dependent on the nature of the R group (primary, secondary, tertiary... 

Whereas base-induced decomposition of N-nitrosourethanes has been utilized (9) as a popular method of generating diazoalkanes, only limited investigations on base treatments of nitrosamides have been reported (10). The primary product in the base treatment is assumed, in analogy to better investigate nitrosourethane cases, to be diazo hydroxides V via attack of a base on the carbonyl group as in IV. A diazo hydroxide V has been related to the diazo ester III by a reaction with benzoyl chloride. 

Concurrent with our investigation on nitrosamine photochemistry (11), we also initiated an investigation of the ground and excited state chemistry of nitrosamides because of a wide discrepancy in the chemical behavior of these two classes of nitroso compounds. For nitrosamines, the presence of extensive delocalization of the unshared electron pair and the tt electrons of the N=0 group as in VI and VII has been well supported by i) n.m.r. evidence of the restricted rotation about the N-N bond (12), ii) electron diffraction analysis revealing the rather short N-N bond... 

In neutral solvent, nitrosamides LXII readily undergo photolysis to give N-acylimines as the primary products which are susceptible to nucleophilic attack due to the conjugated C=N-C0 group (44). Photolysis of nitrosamide LXIIa in methanol gives LXVII (45%) and LXVIII (23%) obviously derived from the nucleophilic addition of methanol to and proton migration of LXVI, respectively. Photolysis of LXIIa in ether gives LXVIII (27%)... 

Broadly, NOC are divided into two groups (a) /V-nitrosamines and (b) N-nitrosamides. In jV-nitrosamines, the two remaining substituent groups on the >N—N=0 atom can be either alkyl or aryl, or they can form the part of a heterocyclic ring (as in N-nitrosopyrrolidine). On the other hand, in N-nitrosamides, more correctly called N-acyl-N-nitroso compounds, one of these... 

Many N-unsubstituted pyrazoles 80 can be obtained from A-allyl-A-nitrosamides 79 (Scheme 46) <1990H(30)789>. Cyclocondensation of -alkoxyvinyl trifluoromethyl ketones 81 with thiosemicarbazide under mild conditions affords 4,5-dihydro-l//-pyrazole-l-thiocarboxamides 82, which can be easily dehydrated with concomitant thiocarboxamide group hydrolysis in concentrated sulfuric acid to give N-unsubstituted pyrazoles 83 (Scheme 47) <1998JFC(92)23>. 

A kinetic model was proposed by Turco et al. [53] with a nitrosamide as an intermediate compound and vanadyl groups were supposed to be the active sites. 

When mixed with the equimolar solution of amides R C(0)NHR (41) in CHCI3, complex 38 reacted quickly at room temperature, yielding up to 95% of A-nitrosamides (42, Fig. 17) (76). Dark-blue solutions of 38 lost their color upon addition of the substrates, which is a reasonable visual test for the reaction. Among the variety of amides (41), only those possessing A-Me substituents were transformed to the corresponding A-nitrosamides (42). No reaction occurred for substrates with bulkier groups. Consequently, no color discharge... 

The amino groups of free amino acids and JV-terminal amino groups of proteins also react with free fatty acids and triacylglyc-erols, yielding the corresponding fatty acid amides. These may be precursors of non-volatile nitroso compounds (nitrosamides) classified as food contaminants (see Section 12.2.7.1). 

All nitroso compounds contain a nitroso group (N=0) in the molecule. The most common nitroso compounds are N-nitroso compounds, which include N-nitrosamines (12-74) derived from secondary amines and N-nitrosamides (12-75) derived from... 

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