Coupling of 2,6-dichloropurine and 2,6-dichlorodeazapurines with ribose and ribose modified sugars

Substituted purine and deazapurine nucleosides are of great interest in med icinal chemistry. Furthermore, 3'-deoxynucleosides exhibit a number of biol ogical activities. In this research the coupling of 2,6-dichloro-1- or 3-de azapurine with protected 3'-deoxyribose is reported. Depending upon couplin g conditions and base structure, different anomeric and isomeric mixtures h ave been obtained. Extensive studies, utilizing chemical and physical metho ds, have been performed to assign the correct configuration to the resultin g nucleosides.