FORMATION OF 2-NITRO-3-METHYLIMIDAZO[4,5-F]QUINOLINE, A DIRECTLY MUTAGENIC PRODUCT, BY NEAR-ULTRAVIOLET IRRADIATION OF A MIXTURE OF 2-AMINO-3-METHYLIMIDAZO[4,5-F]QUINOLINE AND N-NITROSODIMETHYLAMINE

Direct-acting mutagens to Salmonella typhimurium TA98 were found to be formed from heterocyclic amines on exposure to near-ultraviolet light in the presence of N-nitrosodialkylamines. We have isolated the mutagenic photoproduct formed from 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and N-nitrosodimethylamine, and the product was identified as 3-methyl-2-nitroimidazo[4,5-f]quinoline (IQ(NO2)). The yield of IQ(NO2) from IQ was estimated to be 17%. Similar light-dependent activation of IQ was noted with 4 different nitrosodialkylamines other than nitrosodimethylamine. Furthermore, MeIQ and MeIQx were also activated with nitrosamine and light. These reactions represent an example of interaction between 2 different classes of mutagens.