Mutagenic properties of N-cyclopropyl and N-allyl-N-nitroso compounds. Studies on the nature of alkylating species.

A series of directly acting N-nitroso compounds, N-nitroso-N-allyl urea 6, N-nitroso-N-cyclopropyl urea 7, N-nitroso-acetoxymethyl-allylamine 8, N-nitroso-acetoxymethyl- cyclopropylamine 9, N-nitroso(1- acetoxyethyl )allylamine 10 and N-nitroso(1- acetoxyethyl ) cyclopropylamine 11, which may hydrolize to liberate either cyclopropylating or allylating electrophiles, were synthesized and comparatively investigated for mutagenicity in Salmonella typhimurium TA 1535. Hydrolysis rates in aqueous buffered solution do not differ significantly in the allyl- and cyclopropyl series. Analysis of the hydrolysate of all compounds revealed only the presence of allylalcohol and not cyclopropanol . In contrast to the expected equal potencies, due to chemical rearrangement of the alkylating species from cyclopropylcation to allylcation , the results showed that the cyclopropylating analogs were much more effective mutagens than were the allylating compounds. We conclude that for the cyclopropylating compounds the diazonium ion intermediate - and not the free cation - is the alkylating species, during mutagenesis.