ACCESS TO A NEW-TYPE OF HOMO-C-NUCLEOSIDES WITH A SPLIT 8-DEAZAPURINEVIA A 1,3-DIPOLAR CYCLOADDITION REACTION

Upon a 1,3-dipolar addition reaction with trimethylsilyl acetylene, az ides (R,S)-7 were converted to the triazoles (R,S)-8. These diastereoi somers were separated and individually protodesilylated to yield (R)- and (S)-9, fully characterized by NMR. Structural assignments of unsat urated side compounds were deduced from a QUIET-NOESY experiment. Comp ounds (R)-and (S)-9 represent a new type of homo-C-nucleosides with a ''split'' 8-azapurine base moiety.