A NEW APPROACH FOR THE EFFICIENT SYNTHESIS OF OLIGODEOXYRIBONUCLEOTIDES CONTAINING THE MUTAGENIC DNA MODIFICATION 7,8-DIHYDRO-8-OXO-2'-DEOXYGUANOSINE AT PREDEFINED POSITIONS

A combination of H-phoshonate and phosphoramidite chemistry has been applied for the automated solid-phase synthesis of oligodeoxyribonucleotides containing 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodG) residues at predefined positions. The unmodified part of the oligomers has been synthesized by using protected standard phosphoramidites, for the incorporation of 8-oxodG the synthon 2-N-acetyl-5'-O-(4,4'-dimethoxytrityl)-7,8-dihydro-2'-deoxyguanosin-8-one-3'-H-phosphonate, prepared in a five step synthesis via 8-bromo-2'-deoxyguanosine, has been used. This approach combines the advantages of both DNA synthesis strategies in that a high yield of full length oligomers is obtained and unreacted, protected 8-oxodG monomers can be recycled, respectively.