2-(1-Isopropylidene)azino-3-beta and 3-alpha-D-arabinofuranosyl-5-methoxycarbonylmethylenethiazolidine-4-ones (III) and (IV) have been synthesized by condensation of benzylated alpha-chloro-D-arabinofuranose (V) with o-(trimethylsilyl)-2-(1-isopropilidene)azino-5-methoxycarbonylmethylen- thiazolidine-4-one (VI) in the presence of SnCl4 or molecular sieves. Condensation of benzoylated alpha, beta-bromo-D-arabinose (VII) with (VI) led exclusively to the alpha anomer (VIII). 2-(1-Isopropylidene)azino-3-alpha-D-arabinofuranosyl-5-carbamoylmethylene- thiazolidine-4-one (IX) has been synthesized from (IV) (R, R1, R2 = CH3). 1H-N.M.R. and 13C-N.M.R. data confirmed the structures of (III) and (IV) (R, R1, R2 = CH3 and R, R1 = CH3, R2 = Ph). Antiviral activities were tested on monolayer cultures of KB-cells. Whereas previously tested beta-D-ribofuranosyl derivatives had moderate activity, alpha and/or beta-D-arabinofuranosyl derivatives are totally inactive against herpes simplex and poliovirus.