Comparison of mutagenicity and chemical properties of N-methyl-N'alkyl-N-nitrosoureas.

The mutagenic activities of 11 N-methyl-N'-alkyl-N-nitrosoureas were tested on Salmonella typhimurium TA1535 and compared with chemical properties (alkylating activity and decomposition rate). In their relative mutagenicities the N-nitrosoureas that had a cyclic N'-alkyl groups showed far more mutagenic activity than those having a chain N;-alkyl group. M(1-A) NU and M(2-A)NU, which had the most bulky N'-alkyl group in this series, exhibited lethal effects at high concentrations. The mutagenicity showed a small positive correlation with decomposition rates but not with alkylating activities on 4-(p-nitrobenzyl)pyridine. The highest mutagenicity in this series was observed in N-methyl-N'cyclobutyl-N-nitrosourea. These results suggest that, in this series of N-methyl-N'-alkyl-N-nitrosoureas, structural differences in the N'-alkyl groups had great significance in mutagenicity.