Synthesis of Novel Carbocyclic Nucleoside Analogues Derived from 2-(Hydroxymethyl)bicyclo[2.2.1]heptane

Abstract

The key intermediates, [(1R*,2R*,4R*,6R*)-6- (12a) and [(1R*,2R*,4R*,5S*)-5-(hydroxymethyl)- bicyclo[2.2.1]heptan-2-yl]methyl benzoates (12b), were prepared from (1R*,2S*,4R*)- bicyclo[2.2.1]hept-5-en-2-ylmethyl benzoate by hydroboration, oxidation with pyridinium dichromate and subsequent reduction of the thus obtained ketones. The Mitsunobu reaction of12aand12bwith 6-chloropurine afforded 6-chloropurine derivatives, which were converted into others purine analogues. Thymine analogues were prepared from [(1R*,2R*,4S*,6S*)-6- (25a) and [(1R*,2S*,4R*,5S*)-5-aminobicyclo[2.2.1]heptan-2-yl]methanols (25b), which were prepared from alcohols12aand12bin several easy steps.