Bicyclic nucleosides, oligonucleotides, process for their preparation and intermediates

摘要

Compounds of the formula I in the form of the racemates or enantiomers thereof, <IMAGE> (I) in which R1 and R2 independently of one another are hydrogen or a protective group, and B is a purine or pyrimidine radical or an analogue thereof, can be used as antiviral active ingredients or for the preparation of biologically active oligonucleotides.