4'-BRANCHED NUCLEOSIDES .1. MOLECULAR-STRUCTURE OF CONFORMATIONALLY RESTRICTED NUCLEOSIDE ANALOGS 4'-OXYMETHYL-2',3'-ANHYDRORIBOADENOSINE AND 4'-OXYMETHYL-2',3'-ANHYDROLYXOCYTIDINE - SYNTHESIS AND ANTIVIRAL ACTIVITY

Nucleosides with conformational restrictions in the carbohydrate moiet y -4'-oxymethyl-2',3'-anhydroriboadenosine and 4'-oxymethyl-2',3'-anhy drolyxocytidine - were synthesized, subjected to X-ray analysis, and t ested for antiviral activity. Synthesis involved condensation of the c orresponding carbohydrate synthon with silyl derivatives of heterocycl ic bases, with SnCl4 catalysis. The conformations of the resulting mol ecules proved to coincide with those of 2',3'-anhydroriboadenosine and 2',3'-anhydrolyxothymidine studied earlier. However, both 4'-oxymethy l derivatives were devoid of anti-HIV activity; the possible causes of this are discussed.