Application of base-catalysed reaction to the synthesis of dinucleotides containing the four common deoxyribonucleosides and of oligodeoxythymidylates.

The phosphorylation of nucleosides by a nucleoside phosphorofluoridate in the presence of potassium tert-butoxide is a very effective reaction for internucleotide bond synthesis in the case of pyrimidine deoxynucleosides. However, for the purine deoxynucleosides, yields are reduced due to competing reactions. The method was applied to the stepwise synthesis of oligothymidylates. The yield of the trinucleotide was good whereas that of the tetranucleotide was reduced due to the insolubility of the intermediate trinucleotide in the presence of potassium tert-butoxide.