Correlations between topological resonance energy of methyl-substituted benz[c]acridines, benzo[a]phenothiazines and chrysenes, and their carcinogenic or antitumor activities.

In order to clarify the effects of methyl substitution on the carcinogenic activity, each resonance energy (RE) of benz[c]acridines, benzo[a]phenothiazines, chrysene, and their methyl derivatives was calculated by Aihara's TRE theory. Some correlations seem to exist between the values of resonance energy per pi-electron for the cationic species-with the lack of the atom having the highest approximate superdelocalizability (Sr'(E)) from their parents skeleton-and carcinogenic activity.