(±)-4α-Amino-2α,3β-dihydroxy-1α-cyclopentanemethanol (6), the carbocyclic analogue of xylofuranosylamine, was synthesized from the previously reported 4α-acetamido-2α,3α:-epoxycyclopentane-1α-methanol. Amine 6 was converted to (±)-4α-[(5-amino-6-chloro-4-pyrimidinyl)amino]-2α,3β-dihydroxy-1α-cyclopentanemethanol (7) by condensation with 5-amino-4,6-dichloropyrimidine. From 7, the carbocyclic analogues of xylofuranosyladenine and xylofuranosyl-8-azaadenine were prepared. In contrast to 9-d-D-xyIofuranosyladenine and its 8-aza analogue, the corresponding carbocyclic nucleosides were resistant to deamination by adenosine deaminase. The carbocyclic 8-aza derivative 10 exhibited significant in vivo antitumor activity which varied according to treatment schedule.