Chemical reactivity of carcinogenic aminofluorenes: color reactions with montmorillonite.

The hypothesis presented in this article serves a twofold function: (a) a means of predicting whether an aminofluorene is carcinogenic or not and (6) an indication of a possible site in the aminofluorene molecule which is capable of com bining with some cell substance. This study deals with the chemical reactivity of an extensive num ber of aminofluorenes and aminofluorenones and involves their complex formation with montmorillonite, a clay mineral. In a number of cases the above reaction produced marked color changes. There are, however, certain types of montmorillonite clay minerals which are free from ferric iron and do not produce color reactions with aromatic amines (8, 28). A discussion of the chemical and physical properties of montmorillo nite would be out of place in this journal. The reader is, therefore, referred to two books dealing with that subject (5, 13). It will be shown that those aminofluorenes which produce color changes undergo tautomerism, yielding an activated form. Furthermore, it will be postulated that this activated tautomer, a dipole, is involved in carcinogenesis. Color reactions due to complex forma tion of montmorillonite with aromatic amines are not new (4, 6, 8). However, a new mechanism for the color reactions of certain aminofluorenes will be introduced. A method by which carcinogenic activity or inactivity of aminofluorenes can be predicted will be indicated.