Mutagenicity of N-substituted phenanthrene 9,10-imines in Salmonella typhimurium and Chinese hamster V79 cells

Theoretical study concerning the reactivity of imine derivatives of polycyclic aromatic hydrocarbons

The opening reaction of N-protonated polycyclic aromatic hydrocarbon imines has been computed by means of ab initio, density functional, and semiempirical methods of calculation. Imines are predicted to be more stable than the corresponding O-protonated derivatives, epoxides and diol epoxides. On the other hand, the activated N-methanesulfonylbenzene imine presented more favorable DeltaE( not equal ) and DeltaE(r) for ring opening due to the effect of hydrogen-bond interactions. Anti and syn trans-diol benzene imines did not show a different behavior from the unsubstituted imine. According to these calculations, bay-region, fjord-region, and bay-region methyl-substituted compounds opened more easily among the imine derivatives, following the same reactivity pattern as the oxygen analogs. The exothermicity of the opening process correlated with the charge delocalization in the resulting carbocation.

Mutagenicity of K-region oxides and imines of chrysene, benzo[c]phenanthrene and benzo[g]chrysene in Salmonella typhimurium

The K-region oxides and imines of chrysene, benzo[c]phenanthrene and benzo[g]chrysene were investigated for mutagenicity in Salmonella typhimurium TA98 and TA100, using two different exposure media. All six compounds were mutagenic under all four experimental conditions. The imines were 17-3800 times more potent than the corresponding oxides. Omission of KCl (125 mM) from the exposure medium resulted in enhanced mutagenic effects. The enhancement was stronger in strain TA98 (3.1-5.2-fold) than in strain TA100 (1.3-2.5-fold), suggesting an influence on the bacteria rather than on the chemicals.