Structure-activity relationship of nitroimidazo (2,1-b) thiazoles in the Salmonella mutagenicity assay

The mutagenic activity of a series of nitroimidazo (2,1-b) thiazoles was determined in Salmonella typhimurium TA-100 strain by means of the Ames test. A multiple regression analysis showed a highly significant parabolic relationship between mutagenic activity and the Rm values as an expression of the lipophilic character of molecules. The lipophilic character should be important in determining an optimal cell permeation. However when the lipophilic character was expressed by means of the sigma pi values the equation was much less satisfactory. This could be due to the fact that the Rm values of nitroheterocyclic compounds actually represent a measure both of lipophilic and polar character.