Synthesis and anti-hepatitis B virus activity of 9-(2-deoxy-2-fluoro-beta-L-arabinofuranosyl) purine nucleosides

Since the discovery of 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil (L-FMAU) as a potent anti-HBV and anti-EBV agent, we have studied the structure-activity relationships of 2'-deoxy-2'-fluoro-beta-L-arabinofuranosylpyrimidine nucleosides as anti-HBV agents. Therefore it is rational to extend this study to the purine nucleosides. Thus, 3,5-di-O-benzoyl-2-deoxy-2-fluoro-beta-L-arabinofuranosyl bromide (1), which was prepared from L-xylose via a multistep procedure, was coupled with several purines by the sodium salt method. From this general synthesis, 10 purine nucleosides containing the 2-deoxy-2-fluoro-beta-L-arabinofuranosyl moiety have been obtained. The anti-HBV activity and toxicity of the synthesized nucleosides were evaluated in HepG2 2.2.15 cells. Among them, the adenine (10) and hypoxanthine (15) derivatives exhibit good in vitro anti-HBV activity (EC50 = 1.5 and 8 microM, respectively) without significant toxicity up to 200 microM.