Polarographic study of cytosine nucleosides.

The conditions for polarographic reduction of several nucleic acid components were determined. These components were the pyrimidine base cytosine and nucleoside cytidine, and its synthetic analogs arabinosylcytosine and cyclocytidine hydrochloride which are cytotoxic and antileukemic agents. Polarographic reduction, its character and mechanism were studied in aqueous conditions of Britton Robinson buffer at different pH and in nonaqueous conditions of dry dimethylformamide. It was found that the polarographic wave of all compounds had a diffuse character and that the whole process was a two-electron event which in dependence on pH may consist of two one-electron steps. It was demonstrated on the hydrolysis reaction of cyclocytidine hydrochloride to arabinosylcytosine at alkaline pH that the polarographic method may be used for the documentation of structural changes of pyrimidine nucleoside going on in the polarographic chamber.