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.