Electrochemical reduction of 4-thiomethyluracil derivatives

Abstract

Summary The polarographic reduction of 4-thiomethyluracil, 1-methyl-4-thiomethyluracil and 4-thiomethyluridine was investigated by d.c. and a.c. polarography, cyclic voltammetry at HMDE, preparative electrolysis, and coulometry. The reduction mechanisms of the compouds studied were found to be similar, i.e. a two-step reduction in the pH range 1.0–6.0, and merging of the two steps into one at higher pH. In the 1st two-electron reduction step HSCH3 was eliminated. Subsequently, in the 2nd one-electron reduction step, a free radical was formed, which underwent either dimerization to 6,6′-bis-(3,6-dihydropyrimidone-2) or a further one-electron reduction to 3,6-dihydropyrimidone-2. The products obtained were identical to those formed by polarographic reduction of pyrimidone-2 and cytosine. The compounds investigated and their reduction products were strongly absorbed on mercury.