NOVEL ISOMERIC DIDEOXYNUCLEOSIDES AS POTENTIAL ANTIVIRAL AGENTS

Novel isomeric dideoxynucleosides with S,S absolute stereochemistry an d involving the transposition of the base moiety from the normal 1'- t o the 2'-position have been regiospecifically and stereospecifically s ynthesized. The synthetic approaches involved either direct coupling w ith inversion at the 2-position of a preformed dideoxygenated sugar us ing the base moiety as nucleophile (for purine isodideoxynucleosides) or construction of the base moiety onto a stereochemically defined ami no sugar precursor (pyrimidine isodideoxynucleosides). These compounds possess extremely high stability with respect to ''glycosidic'' bond cleavage and enzymatic deamination. Antiviral data suggest that the mo st active compound was levorotatory S,S-isodideoxyadenosine.