Characterization of directly acting mutagens produced from N-nitroso-N-(formylmethyl)alkylamines: their possible involvement in the carcinogenesis of N-nitrosamines having a 2-hydroxyethyl group.

Directly acting mutagens formed from N-nitroso-N-(formylmethyl)alkylamines (3) were isolated and identified as N-nitroso-N-alkyl-1-hydroxyimino-2-oxoethylamines (4). Their structures were elucidated on the basis of nuclear magnetic resonance spectra and confirmed by derivatization to the crystalline 2,4-dinitrophenylhydrazones (5). Compounds 4 (alkyl =ethyl and butyl) were strongly mutagenic to Salmonella typhimurium TA 1535 and Escherichia coli WP2 hcrwithout metabolic activation, while 4 with a tert-butyl group was not mutagenic. The formation of 4 is considered to proceed by the nitrosation of 3, indicating a possible involvement of the formylmethyl metabolite in carcinogenesis by N-nitiosamines with a 2-hydroxyethyl group.