AN EFFICIENT SYNTHESIS OF RADIOISOTOPICALLY LABELED OLIGONUCLEOTIDES THROUGH DIRECT SOLID-PHASE 5'-PHOSPHITYLATION

Oligonucleotides were labeled by the direct coupling of [C-14]- or [H- 3]DMT-nucleosides (2) with a CPG-bound 5'-oligonucleotide phosphoramid ite 6. High radiochemical yield was achieved, by examining the quality of each batch of 6, before coupling, and by recovering 2, after coupl ing.