Synthesis of 1-(2-hydroxyethyl)-1-nitrosourea and comparison of its carcinogenicity with that of 1-ethyl-1-nitrosourea.

1-(2-Hydroxyethyl)-1-nitrosourea (HNU) was prepared by the action of nitrosyl chloride on (2-hydroxyethyl)urea. Attempts to synthesize HNU by an earlier described method were unsuccessful and led to the formation of the cyclized derivative 1-nitroso-2-oxazolidone. In addition, the spectral data that we obtained for HNU differed from those reported earlier. Female C57BL/Cbl mice were treated with single ip doses of HNU to determine its median lethal dose (LD50) and its ability to induce lymphocytic thymic lymphomas in these mice. The results showed that the LD50 was the same as that for 1-ethyl-1-nitrosourea (ENU) and that its was slightly more potent than ENU as a carcinogen in this system.