Versatile introduction of azido moiety into oligonucleotides through diazo transfer reaction.

The use of a diazo transfer (DZT) reagent enables clean and efficient conversion of aminated oligodeoxyribonucleotides (ODNs) into their azido counterparts under mild conditions. ODNs bearing an amino tether at the 3', 5', or any internal position could be modified in this manner thus demonstrating the versatility of this reaction. Easy access to such azido-modified ODNs is of great interest for conjugation in particular through copper catalyzed 1,3-dipolar cycloaddition (CuAAC reaction).