(α-Pyridyl) methyl phosphoro-bis-triazolide as a new phosphorylating reagent for internucleotide bond formation.

(α-Pyridyl)methyl phosphoro-bis-triazolide has been found to be a reagent of choice for phosphate protection in oligodeoxyribonucleotide synthesis. The reagent has been used successfully to phosphorylate all the four 5'-and N-protected deoxynucleosides. The resulting 3'-phosphorylated derivatives were found to be fairly stable as either triethyl ammonium salts or cyanoethyl derivatives. The phosphorylated derivatives were used in the preparation of the dimers TpT and d(ApT) in solution phase and a tetramer, TTTT, and a hexamer, d(ATATAT), on solid phase using glass support. The method gave excellent yields. Considerably reduced condensation time (6-9 min) and practically no cleavage of the internucleotide bond during the removal of the group are the advantages.