Kinetics of nornicotine and anabasine nitrosation in relation to N′-nitrosonornicotine occurrence in tobacco and to tobacco-induced cancer

The kinetics of nornicotine and anabasine nitrosa-tion, studied in aqueous solution, obeyed equations typical for the nitrosation of aliphatic secondary amines, with third-order stoichiometric rate constants of 1.15 (nornicotine) and 0.86 (anabasine) m^–2 sec^–1. The similarity of the two rate constants suggested that the nitrosonornicotine occurring in tobacco arises from nicotine rather than nornicotine, because tobacco contains anabasine but apparently does not contain nitro-soanabasine. The high rate constants suggested that in vivo nitrosation of these secondary amines may constitute a hazard to tobacco smokers and chewers, in addition to that presented by preformed nitrosonornicotine.