Molecular Geometry and Mechanisms of Action of Chemical Carcinogens

1,3-Bis(3-nitrophenyl)triazene

“…N3~N4 [1.261 (2)~,] is longer than expected for a double bond, N2--N3 [1.326 (2) A] is shorter than expected for a single bond, and C5--N2 and C ll--N4 are both short for single C~r--N bonds; there is clear evidence of a resonance effect in this part of the molecule. In view of the carcinogenic activity of some azobenzene derivatives (Kurosaki et al, 1976) closely related to their conjugation structure (Arcos & Arcos, 1962), we think that the resonance effect in the triazene group in triazene derivatives might be related to their antitumour activity. While the nitro groups 03--N5--O4 and O1--N1--O2 are twisted by 3.3 (2) and 6.7 (2) ° from their benzene planes, the dihedral angle between the two phenyl rings is 6.2 (2) °, and the torsion angles C5--N2--N3--N4 and N2--N3--N4----CI1 are 179.4(1) and 179.6(1) ° , respectively, showing the near coplanarity of the whole molecule.…”

Pathology of Experimental Neurogenic Tumors Chemically Induced During Prenatal and Postnatal Life

“…Until now, however, there was no direct experimental evidence regarding the alkylation of nucleic acids as the primary step in carcinogenesis. Other mechanisms have been proposed, e.g., denaturation (Arcos & Arcos, 1962;Argus et nl., 1965) and alkylation of cell proteins (Magee & Hultin, 1962). In any theory, however, one must take into account the fact that the carcinogenic changes are not only irreversible and persistent but also transmitted to the daughter cells.…”