Polarographic reduction of adenine and its 9-(?,?-dihydroxy-2-alkyl) derivatives

Abstract

The polarographic reduction of adenine and its 9-(α,ω)-dihydroxy-2-alkyl) derivatives on a short-period mercury electrode in strongly acidic media is determined by the rate of diffusion of the corresponding cations and, at pH values that exceed the pKa values, by the kinetics of surface protonation of the uncharged molecules; this was proved by the dependence of the limiting current on the height of the mercury column, the temperature, and the depolarizer concentration. The polarographic reduction of adenine, adenosine, 9-(α,ω-di-hydroxy-2-alkyl)adenines, and the corresponding phosphates in acidic media proceeds with the loss of sic electrons per molecule. The similar trends of the change in the half-wave potentials and the numerical pKa values is associated with the fact that the site of protonation is simultaneously the site of nucleophilic attack by the electron during electrical reduction.