Small Scale Synthesis of Labeled Diphenyl and Its Binding to Mouse Liver Microsomes

Abstract

For safety evaluation of diphenyl, a food additive, in Japan, labeled Biphenyl was synthesized by reaction of thallium (I) bromide with phenylmagnesium bromide which is prepared from bromobenzene-U-¹⁴Cin ether. The formation of labeled diphenyl in high yield made it possible to study the binding of diphenyl to mouse hepatic microsomes. Diphenyl with high specific activity formed the covalent binding to microsomes after metabolic activation. However, effects of two inducers, benzo (a) pyrene and KC-500, on the binding activitiy of diphenyl were not clear under our experimental conditions. The data reported here seem to be valuable from the view point on safety evaluation on food additives.