Mutagenicity to Salmonella of the mono methylamino and N-cyanoethyl analogues of 4-dimethylaminoazobenzene (DAB) and 6-dimethylaminophenylazobenzthiazole (6BT).

Replacement of one of the methyl groups of the carcinogens 4-dimethylaminoazobenzene (DAB) and 6-dimethylaminophenylazobenzthiazole (6BT) with a cyanoethyl (-CH2CH2CN) substituent dramatically increases their mutagenic potency to Salmonella (strain TA98). The corresponding monomethylamino derivatives (-NHCH3) are more mutagenic than the parent dimethylamino [-N(CH3)2] compounds, but substantially less mutagenic than the cyanoethyl derivatives. All of these mutagenic activities are liver-S-9-dependent. The very similar dose response curves observed for the two cyanoethyl compounds argues for the formation of a common electrophilic intermediate from each.