STRUCTURE AND REDOX PROPERTIES OF ONE-ELECTRON OXIDIZED RADICALS FROMADENINE AND DERIVATIVES

The reaction of sulphate radical anion (SO4.-) with adenine and its de rivatives results in the formation of a neutral radical at pH 7, whose spin distribution and hence the oxidizing properties are strongly dep endent on the position and nature of the substituents. This reaction p roceeds by one electron transfer, followed by rapid deprotonation of t he incipient radical cation, the sequence of these reactions being equ ivalent to hydrogen abstraction. In adenine radical cation, deprotonat ion was found to occur either from N-6-H or N(9)-H, leading to the for mation of a strong and a less oxidizing radical, respectively. Among a denine derivatives, adenosine was shown to give rise to the most oxidi zing neutral radical, whilst the least oxidizing radical was formed fr om N-6,N-6-dimethyladenine.