Racemic synthesis of carbocyclic purine nucleoside analogues with restricted glycosyl conformation

Abstract

Carbocyclic purine nucleoside analogues which have restricted glycosyl conformation at χ ≈ 180° were designed, based on the conformational features of the L-nucleotide residue in heterochiral DNA, and synthesized. The synthesis of (±)-carbocyclic 8,6′-O-anhydro-8,6′-dihydroxy-2′-deoxyadenosine 3 was achieved by intramolecular cyclization of the 8-bromo-6′-O-tosyl-2′-deoxyadenosine derivative. (±)-Carbocyclic 8,6′-O-anhydro-8,6′-dihydroxy-2′-deoxyguanosine 4 was synthesized from the carbocyclic 2,6-diaminopurine nucleoside derivative via the carbocyclic 8-bromo-6′-O-mesyl-2′-deoxyguanosine derivative.