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 nitrosation, 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 nitrosoanabasine. 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.