4-Nitrobenzyl as aN-Protective Group inN-Heterocycles: An Easy Access to 7-Arylmethyladenines from 3-(4-Nitrobenzyl)-adenine

The 4-nitrobenzyl group is used as a N-3 protective group in adenine to direct further alkylation (benzylation) at the 7-position. In the obtained 7-arylmethyl-3-(4-nitrobenzyl)adenines, this protective group is removed, presumably as quinonimine methide, by reduction of the nitro group by the use of sodium dithionite, thus leaving 7-arylmethyladenines.