FACILE METHODS TO RECYCLE NUCLEOSIDES DURING SOLID-PHASE SYNTHESIS OFOLIGONUCLEOTIDES

Solid phase syntheses of oligonucleotides, using nucleoside phosphoram idites or methylphosphonamidites require a large excess of nucleoside monomers over the hydroxy functions of the growing oligonucleotide cha in bound onto the solid phase. The outlined method allows to recover t he excess nucleosides. All the protective groups on the sugar and the nucleobase of the monomers are maintained throughout the recycling pro cess.