Reversible modification of oligodeoxynucleotides: click reaction at phosphate group and alkali treatment

We characterized click reaction between oligodeoxynucleotides (ODNs) possessing acetylene groups at the phosphate unit and azide compounds. Cu(I)-catalyzed cycloaddition proceeded efficiently to form the corresponding functional ODNs. The resulting ODNs could be converted into ordinary ODNs by treatment with aqueous methylamine. The present method successfully achieved a reversible modification of ODNs.