Structure and carcinogenic activity of azo dyes.

In recent years many investigations have been carried out on the carcinogenic activity of several groups of derivatives of 4-aminoazobenzene, their spectra, the relative basicities of their nitrogen atoms, and their metabolism (1, 2, 9, 14). The principal results on the correlation of structure and activity are as follows: Methylation.--3'-Methyl-4-dimethylaminoazobenzene is a tvery potent carcinogen, the 2'and 4'-methyl derivatives are fairly strong ones, whereas the 2and 3-methyl derivatives lack carcinogenic activity (3, 7, 8).