Synthesis of oligonucleotides containing Fapy.dG (N(super 6)-(2-deoxy-alpha,beta-D-erythropentofuranosyl)-2,6-diamino-4-hydroxy-5-foramidopyrimidine) using a 5'-dimethoxytrityl dinucleotide phosphoramidite

An improved method for synthesizing oligonucleotides containing Fapy.dG, which does not require reverse phosphoramidites, is described. Fapy.dG containing dinucleotide phosphoramidites containing 5'-thymidine or 5'-deoxycytidine are prepared and employed in oligonucleotide synthesis.