Synthesis Of Conformationally Restricted Bicyclic 3 '-Azido/Amino-Xylofuranosylpyrimidines

Conformationally rigid 3'-azido-3'-deoxy-2'-O,4'-C-methylene-xylofuranosylpyrimidines have been synthesized from dihydroxysugar precursor, 3-O-benzyl-4-C-hydroxymethyl-1,2-O-isopropylidene-a-D-ribofuranose following a convergent methodology in good yields. The dihydroxy sugar precursor was conveniently synthesized from diacetone-D-glucose following a literature procedure. As a model case, it is demonstrated that 3'-azido-3'-deoxy-2'-O,4'-C-methylene-xylofuranosylthymine can easily be converted into corresponding bicyclic 3'-amino-nucleoside in quantitative yield by its treatment with Pd-C under hydrogen atmosphere.