Structure-mutagenicity relationships within a series of para-alkoxynitrosobenzenes

The mutagenic potential of para-alkoxynitrosobenzenes (para substituents, -OCH3, -OC2H5, n-OC4H9, n-OC5H11 and n-OC12H25) and p-phenoxynitrosobenzene was investigated in the Ames test. The order of mutagenic activity within a series of p-alkoxynitrosobenzenes was as follows: p-ethoxy greater than p-methoxy greater than p-butoxy (n) greater than p-pentyloxy (n) greater than p-dodecyloxy (n), the last being inactive. A relationship between mutagenic activity and electronic property of different substituents indicated in the alkoxy series, that as the Hammett constant decreased or bulk of the substituent (except methoxy) increased, the activity was found to decrease.