Nucleosides. IX. Synthesis of Purine<i>N</i>³,5′‐Cyclonucleosides and<i>N</i>³,5′‐Cyclo‐2′,3′‐seconucleosides via Mitsunobu Reaction as TIBO‐like Derivatives

Abstract

The Mitsunobu reaction was applied to prepare, in one step, purine N 3,5′‐cyclonucleosides 10a–d. A subsequent ring opening in the ribose moiety of the resultant N 3,5′‐nucleosides by sodium periodate led to the corresponding N 3,5′‐cyclo‐2′,3′‐seconucleosides. These products consist of 5‐, 6‐, and 7‐membered tricyclic system which is the basic skeleton of TIBO derivatives, known antiviral agents.