Directly-acting mutagens formed from N-nitroso-N-(formylmethyl)alkylamines

Directly-acting mutagens formed from N-nitroso-N-(formylmethyl)alkylamines (I) were isolated and identified as N-nitroso-N-alkyl-1-hydroxyimino-2-oxoethylamines (II). Their structures were elucidated on the basis of nuclear magnetic resonance spectra and confirmed by leading to their crystalline 2,4-dinitrophenylhydrazone. II (alkyl = ethyl and n-butyl) were strongly mutagenic to Salmonella typhimurium TA1535 and Escherichia coli WP2 hcr- without metabolic activation, while II with a tert-butyl group was not mutagenic. The formation of II from I is considered to proceed by the nitrosation of I, indicating a possible involvement of a formylmethyl metabolite in the carcinogenesis of nitrosamines with a 2-hydroxyethyl group.