Structure-activity relationship within a series of m-diaminobenzene derivatives

We investigated the mutagenicity of m-diaminobenzene (m-phenylenediamine) and four 2,4-diaminoalkylbenzenes (methyl, ethyl, isopropyl and n-butyl) in Salmonella typhimurium strains TA100, TA1538 and TA98 in the absence and presence of S9 induced by Acoclor 1254. m-Diaminobenzene was the most active mutagen, followed by 2,4-diaminotoluene and 2,4-diaminoethylbenzene, resp. Negative response was observed for both 2,4-diaminoisopropylbenzene and 2,4-diamino-n-butylbenzene. Thus, depending on the size of the substituting alkyl group at the C1 position of 2,4-diaminoalkylbenzene, a decline and loss of mutagenic activity was observed.