SYNTHESIS OF PURINE AND PYRIMIDINE 3'-AMINO-3'-DEOXYXYLONUCLEOSIDES AND 3'-AMINO-2',3'-DIDEOXYXYLONUCLEOSIDES

A general procedure to obtain the 3'-aminoxylonucleosides 13a,b and 17 a,b is presented. The synthetic scheme is based on the 5' directed int ramolecular nucleophilic substitution at the 3'-activated position of the nucleoside. The approach of the incoming group to this position ta kes place regio- and stereoselectively from the most hindered face of the nucleoside, The methodology presented is applicable to ribonucleos ides and 2'-deoxyribonucleosides, regardless of their nitrogenated bas e.