A series of 2-amino-9-(3-hydroxymethyl-4-alkoxycarbonyloxybut-1-yl) purines (4-10) and 2- amino-9-(2-(2-oxo-1, 3-dioxan-5-yl) ethyl) purine (1) were synthesized as potential prodrugs of penciclovir and evaluated for their oral penciclovir bioavailability in mice and rats. Treatment of 2-(2-benzyloxyethyl) propane-1, 3-diol (11) with 1, 1'-carbonyldiimidazole in THF followed by hydrogenolytic removal of the benzyl group of the resulting cyclic ...