1-DEAZA-2'-DEOXYADENOSINE - PHOSPHONATE AND PHOSPHORAMIDITE BUILDING-BLOCKS FOR SOLID-PHASE OLIGONUCLEOTIDE SYNTHESIS

The synthesis of the 3'-[(2-cyanoethyl)diisopropylphosphoramidite] (3b) and the 3'-phosphonate (3a) of 1-deaza-2'-deoxyadenosine (1b) is described. For this purpose compound lb was protected at the 6-amino group with a benzoyl residue. Ensuing 4,4'-dimethoxytritylation of lb and phosphitylation afforded the P(III) derivatives(3a) and (3b). They were successfully employed in solid-phase oligodeoxyribonucleotide synthesis of d(c1A-c1A-c1A-A-A-A) (6). C-13-Nmr and N-15-nmr spectra of the compounds (1-5) are discussed.