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Prior to this work only two examples of carbanucleosides possessing a C-1′/C-6′ double bond had been reported and they were minor derivatized side products arising during other targeted syntheses. To develop this structural feature into a new class of potential antiviral agents, the 5′-nor derivative of aristeromycin with such an olefinic structure (6) represents the first example. In this regard, treatment of (1′S,2′S,3′S,4′R,5′S)-6-chloro-9-(2′,3′-isopropylidenedioxy-6′-oxabicyclo[3.1.0]hex-4′-yl)purine (7) with sodium methoxide yielded 6 via an E′2-like elimination pathway. A convenient way to the C-4′ epimer of 6 (that is, 17) also arose during these studies and is described. Antiviral analysis of 6 and 17 failed to produce any significant activity. [Copyright &y& Elsevier]

Abstract: Formycin is a naturally occurring biologically responsive C-nucleoside. In pursuing the design and syntheses of novel C-nucleosides, convenient access to carbocyclic C-nucleosides based on the formycin framework was a goal. One such target was carbocyclic 4′-epi-formycin (4). This compound is reported via a procedure based on an asymmetric aldol/ring closure metathesis strategy. To provide a preliminary glimpse into the biological characterization of 4 an antiviral assay was conducted. Target 4 was found to be inactive and to lack cytotoxicity to the host cells. [Copyright &y& Elsevier]

Abstract: Formycin is a naturally occurring C-glycoside (C-nucleoside) that possesses antitumor, antibacterial, antifungal, and antiviral activity. In connection with our ongoing interest in the design and syntheses of C-nucleoside derived antiviral agents this report describes the preparation of carbocyclic formycin and its 7-hydroxy (oxo) analog lacking the C-4′ hydroxylmethylene moiety in racemic form (4 and 6, respectively). An antiviral analysis of (±)-4 did not disclose any activity. [Copyright &y& Elsevier]