³¹P and ¹H NMR investigation of the structure of the phosphorylating intermediates in the phosphodiester approach to the oligonucleotide synthesis

Abstract

The structure of the reactive phosphorylating derivatives (B) formed by treatment of pdT(Ac) and of the model compound phenylphosphate with condensing reagents in pyridine was studied. Using γ-picoline instead of pyridine it was demonstrated by phosphorus and proton NMR spectroscopy that B contains γ-picoline residue attached to P atom readily exchangable with free γ-picoline. Thus in B type derivatives phosphomonoester group is converted to phosphoryl pyridinium residue.