Dimethylnitrosamine, structure

A H NMR spectrum of /V,/V-dimethylnitrosamine (38) was obtained as early as 1957, and the free energy of activation for rotation was determined to be ca. 23 kcal/mol at 215°C (74). This high a barrier in nitrosamines is reasonable because the canonical structure 39 is stabilized by the strongly electron-donating ability... 

We have subjected the mechanistic proposal of Fig. 1 to a direct test. N,N-Dimethylformaldimmonium ion was independently prepared as its trifluoroacetate salt and was mixed with a slight excess of silver nitrite in acetonitri1e-d3. The only product identified was dimethylnitrosamine, which was produced in greater than 90% yield ( ). No direct evidence for intermediates of structure I could be obtained, as the reaction was complete within the few minutes required to analyze the mixture by running its NMR spectrum. 

Dimethylnitrosamine (DMN) is by far the most extensively studied nit-rosamine. Investigations of DMN metabolism in vitro are summarized in Table XII. As in the other sections of this article, Table XII is not an exhaustive literature survey, but represents a cross-section of studies on DMN metabolism. We have not included studies of the binding of DMN to cellular macromolecules. The large number of studies of DMN metabolism compared to other nitrosamines is partially a result of the relative structural simplicity of DMN. The major metabolite resulting from a-hydroxylation is formaldehyde. Assays for formaldehyde as a measure of DMN demethylase activity are available (474). 

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