The carcinogenic and electrophilic activities of N-benzoyloxy derivatives of N-methyl-4-aminoazobenzene and related dyes.

The N-benzoyloxy derivatives of N-methyl-4-aminoazobenzene, its 4'-methyl and 4'-ethyl derivatives, and N-ethyl-4-aminoazobenzene were synthesized for comparison of their carcinogenic activities and their reactivities with nucleophilic reagents. Each of the 4 esters had a similar degree of nonenzymatic reactivity with methionine and guanosine at neutral pH. Each of the dyes induced sarcomas at the site of s.c. injection in rats, but N-benzoyloxy-N-methyl-4-aminoazobenzene was considerably more carcinogenic than were any of the other dyes. N-benzoyloxy-N-methyl-4-aminoazobenzene was also more stable in neutral lipid, and this stability may have contributed to its greater carcinogenicactivity. Neither the electrophilic reactivities nor the s.c. carcinogenicities of these dyes paralleled the hepatocarinogenic activities of the parent dyes.