A-Nitrosopyrrolidine

TABLE 27. A comparison of selected torsional angles (degrees) of 3-phenyl-A-nitrosopyrrolidine, 81, as calculated by MM2 and measured by X-ray crystallography"... 

The extent of formation of these NOC depends upon the presence of nitrogen oxides present in the atmosphere during the manufacturing cycle. The major contaminants are NDMA, A-nitrosodiethylamine (NDEA), A-nitrosopyrrolidine (NPYR), NMOR, A-nitrosodiphenylamine (NDPhA), A-nitrosopiperidine (NPIP) and A-nitrosodibutylamine (NDBA)68. NMOR was found in the hot process areas NDMA occurred in tube production areas in which NDPhA was being used as retarder and tetramethylthiuram disulphide as an accelerator. Figure 12 shows a proposed reaction scheme of formation of NOC in the rubber industry and subsequent exposure67. 

Fig. 1 Chemical formulas of some A-nitroso compounds (a) A-nitrosodimethylamine (NDMA), (b) A-nitrosodibenzylamine (NDBzA), (c) A-nitrosopyrrolidine (NPYR), (d) A-nitrosoprolin (NPRO), (e) A-ni-troso-4-hydroxyproline (NHPRO), (f) A-nitroso-2-(hydroxymethyl)-thiazolidine-4-carboxylic acid, (g) A-nitroso-D-fructose-L-histidine, (h) A-nitroso-1,2,3,4-tctrahydro-/3-carboline-3-carboxylic acid.

A-Nitrosopyrrolidine (85) with phenyllithium gives 86, which with DMAD forms the pyrrolo [ 1,2-6]pyrazole (88), possibly through the dipolar intermediate 87.111... 

For the estimation of volatile dialkyl nitrosamines and A-nitrosopiperidine, A-nitrosopyrrolidine and A-nitrosomorpholine, ION sulphuric acid was added to the sample which was then extracted with redistilled dichloromethane. 1.5m sodium hydroxide was added to the combined extract. After separation, the organic layer was dried over sodium sulphate and evaporated to 2.5mL at 46°C on a water bath. Hexane was added, and evaporation continued to about 250pL. Ahquots of 5pL were analysed for volatile nitrosamines using gas chromatography. 

This type of hydrogen bonding is termed symmetric in contrast to the more common unsymmetric form. Symmetrical hydrogen bonds form in only the strongest bonded systems. These are frequently anionic like FHF and the carboxylales mentioned above. An example of a strong, symmetric hydrogen bond in a cation is the bis(A -nitrosopyrrolidine)hydrogen cation (Fig. 8.5). >2... 

The extraction of A-nitrosopyrrolidine (Fig. 5.8) from bacon involves the use of a cyanopropyl column, and the mechanism is hydrogen bonding between the amino nitrogen of the A-nitrosopyrrolidine and the underlying silica surface, as well as an interaction between the propyl carbons and the analyte. The sample is applied as a solution of hexane and methylene chloride, which solubilizes the bacon and does not interfere with the separation of the analytes by hydrogen bonding. The eluent contains methanol, which breaks up the bonding and effectively solubilizes the A-nitrosopyrrolidine. 

Figure 5.8. Structure of A -nitrosopyrrolidine extracted from bacon.

A/-nitrosopyrrolidine (NPYR) A/-nitrosopiperidine (NPIP) /V-nitrosothiazolidine A/-nitrosomorpholine (NThZ) (NMOR) ... 

A -nitrosodiethylamine, A -nitrosodipropylamine, A -nitrosodibutylamine, A -nitrosopiperidine, A -nitrosopyrrolidine, A -nitrosomorpholine Tobacco- specihc A -nitrosamines... 

Several instances where the per cigarette yield range differs significantly in two different publications, for example, the per cigarette yield range for A-nitrosopyrrolidine is listed as 1.5 to 110 ng in (1727) and 3 to 60 ng in (1740). 

NDMA = A-nitrosodimethylamine NDEA = A-nitrosodiethylamine NDPA = A-nitrosodipropylamine NDBA = A-nitrosodibutylamine NDELA = A-nitrosodiethanolamine NPIP = A-nitrosopiperidine NPYR = A-nitrosopyrrolidine NPRO = A-nitrosoproline NMOR = A-nitrosomorpholine NSAR = N- nitrososarcosine... 

Hansen, T., W. Iwaoka, L. Green, and S.R. Tannenbaum Analysis of A-nitrosoproline in raw bacon. Further evidence that nitrosoproline is not a major precursor of A-nitrosopyrrolidine J. Agr. Food Chem. 25 (1977) 1423-1426. 

A07. Chung, F.L., A. Juchatz, J. Vitarius, and S.S. Hecht Effects of dietary compounds on a-hydroxylation of A-nitrosopyrrolidine and A -nitrosonornicotine in rat target tissues Cancer Res. 44 (1984) 2924. 

A08. Chung, F.L., A. Juchatz, J. Vitarius, B. Reiss, and S.S. Hecht Inhibition of target tissue activation of A -nitrosonornicotine and A-nitrosopyrrolidine by dietary components in A-Nitroso compounds Occurrence, biological effects and relevance to human cancer, edited by I.K. O Neill, R.C. von Borstel, C.T. Miller, J. Long, and H. Bartsch, lARC, Lyon, Erance, lARC Sci. Publ. No. 57 (1984) 797-804. 

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