Racemic synthesis of carbocyclic purine nucleoside analogues with restricted glycosyl conformation

Carbocyclic purine nucleoside analogues which have restricted glycosyl conf ormation at chi approximate to 180 degrees were designed, based on the conf ormational features of the L-nucleotide residue in heterochiral DNA, and sy nthesized. The synthesis of(+/-)-carbocyclic 8,6'-O-anhydro-8,6'-dihydroxy- 2'-deoxyadenosine 3 was achieved by intramolecular cyclization of the 8-bro mo-6'-O-tosyl-2'-deoxyadenosine derivative. (+/-)-Carbocyclic 8,6'-O-anhydr o-8,6'-dihydroxy-2'-deoxyguanosine 4 was synthesized from the carbocyclic 2 ,6-diaminopurine nucleoside derivative via the carbocyclic 8-bromo-6'-O-mes yl-2'-deoxyguanosine derivative.