[Synthesis of 5'-phosphorylated oligodeoxyribonucleotides by the H-phosphonate method]

N,O-protected 2'-deoxyribonucleotide-3'-H-phosphonates and 2-(p-nitrophenylethyl)-H-phosphonate were prepared and used in solid-phase synthesis of 5'-phosphorylated DNA. H-Phosphonate condensation is performed with 1:2 ratio of P-component to activator (pivaloyl chloride). Protection groups were removed either by sequential treatment with conc. NH3 and DBU or by combination of these reagents.