Abstract
The study of some 4-aroyl-1-(2-chloroethyl)-1-nitrosohydrazinecarboxamides with a Saccharomyces cerevisiae mutagenicity test of increased sensitivity defined two of them, 4-(4-bromobenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarboxam ide and 4-(4-fluorophenyl)-1-(2-chloroethyl)-1-nitrosohydrazine carboxamide as typical cytostatic agents. At concentrations of 2-5 microg/ml the substances kill up to 60%-70% of cells without having any detectable recombinogenic and mutagenic effects. At the same concentrations, lomustine, well known as a cytostatic reference, demonstrated recombinogenic and mutagenic activity on yeast cells. The advantage of the newly synthesized substances is that, in a certain concentration range, their biological activity is mainly cytotoxic without induction of recombinogenic and mutagenic events in surviving cells.