Synthesis and antiviral evaluation of 4′-alkoxy analogues of 9-(β-D-xylofuranosyl)adenine

Background: Motivated by the reported biological activity of 9-(β-D-xylofuranosyl)adenine (xylo-A), the synthesis of its 4′-alkoxy analogues was carried out. Methods: The starting material 9-(3-deoxy-β-D-glyceropento-3-enofuranosyl)adenine (1) was prepared from adenosine. Compound 1 was converted to the 2′,5′-bis-O-(tert-butyldimethylsilyl) derivative (2) and then to the N⁶-pivaloyl derivative (3). When 3 was reacted with meta-chloroperbenzoic acid in the presence of a series of alcohols, the β-D-isomer of the respective 4′-alkoxy derivative was obtained exclusively in high yield. Deprotection of these products led to the isolation of the desired 4′ alkoxy analogues (8a-l) of xylo-A. Results: Antiviral evaluation revealed that none of these analogues showed inhibitory activity against a wide variety of DNA and RNA viruses. Conclusions: We assume that conformational difference of the sugar moiety of 8a-l from that of xylo-A could be attributable to their inactivity.