Electrochemical reduction of ammonium 5-bromo-2′-deoxyuridine-5′-methylphosphonate: an inhibitor of cell growth

The electrochemical reduction of a cell growth inhibitor, ammonium 5-bromo-2′deoxyuridine-5′-methylphosphate (BrdUrdOPO₂Me), was investigated in order to compare its electrochemical properties with those of 5-bromo-2′-deoxyuridine (BrdUrd) and of 5-bromo-2′-deoxyuridine-5′-phosphate (BrdUMP). The derivatives f BrdUrd differ markedly in their electrochemical behavior from BrdUrd because of the influence of the methylphosphonate or phosphate groups. Current vs pH plots for BrdUrdOPO₂Me and BrdUMP decrease in the form of an acid dissociation curve and assume kinetic behaviour at high pH values. Controlled potential electrolysis at a stirred mercury cathode of BrdUrdOPO₂Me requires two electrons per mole. Autoradiochromatographic analysis of the electrolytic product of the tritium labeled ammoniumbromodeoxyuridine-5′-methyl[³H]phosphate shows that the methylphosphonate group remains intact during the course of the electrolysis. Electrolysis results in debromination and the product exhibits an uv spectrum identical to a 2′-deoxyuridine derivative.