AN AZIRIDINIUM ION INTERMEDIATE IN THE NITROSATION OF A HEXETIDINE MODEL

The nitrosation chemistry of 1,3,5-trimethyl-5-aminahexahydropyrimidin e (2) has been investigated as a model for the behavior of the antimic robial agent hexetidine (1) under similar conditions. The reaction of 2 with sodium nitrite in glacial acetic acid gives ethylnitrosamino)me thyl]-3-nitroso-1,3-oxazolidine (4) as the major nitrosamine. This com pound arises from a molecular rearrangement which proceeds through the diazotization of the primary amino group followed by intramolecular d isplacement of nitrogen to generate an aziridinium ion. The N-nitrosoo xazolidine 4 forms from the nitrosation of an imidazolidine produced f rom the aziridinium ring hydrolytic opening. The N-nitrosooxazolidine 4, an isomer, ethylnitrosamino)methyl]-3-nitroso-1,3-oxazolidine (14), which is not formed in the nitrosation of 2, and an analog exyl)nitro samino]methyl]-3-nitroso-1,3-oxazolidine (22) have been independently synthesized. The N-nitrosooxazolidine 22 which would be formed from he xetidine is not present in its nitrosation mixture, suggesting the abs ence of reactive aziridinium ions in that case. The dissimilar nitrosa tion chemistry of 2 and 1 are discussed.