132540-75-1Relevant articles and documents
Mechanism of the Reaction of Carbon and Nitrogen Nucleophiles with the Model Carcinogens O-Pivaloyl-TV-arylhydroxylamines: Competing SN2 Substitution and SN1 Solvolysis
Helmick, John S.,Martin, Kristy A.,Heinrich, Julie L.,Novak, Michael
, p. 3459 - 3466 (2007/10/02)
The reaction of N,N-dimethylaniline (4) and aniline (5) with the O-pivaloyl-N-arylhydroxylamines 1a-f) in MeOH exhibits second-order kinetics and generates products of nucleophilic attack on the nitrogen of the hydroxylamine derivative. The characteristics of this reaction are not consistent with a nitrene or SET mechanism, an SN1 reaction with rate-limiting attack of the nucleophile, or nucleophile-assisted ionization. The only mechanism consistent with the available data, including substituent effects (ρ+ ≈ -3.0), cyclic voltammetry results, and product identifications, is an SN2 process. This reaction occurs in competition with an SN1 solvolysis that shows significant substituent dependence (ρ+ = -8.5). The reaction of 1 with 5 generates products of nucleophilic attack by both carbon (8, 9) and nitrogen (10). Competitive attack by carbon apparently occurs because of transition-state stabilization caused by the incipient C-N bond. The successful competition of the 8N2 reactions with SN1 solvolysis for the esters 1a and 1b, which are similar in reactivity to the putative carcinogens 2a-c, indicates that certain adducts isolated from in vivo experiments, including 3, may be formed via SN2 mechanisms.
