Synthesis of cross-linked circular DNAs using Hüisgen reaction

Triazole-cross-linked ODNs were synthesized using Hüisgen reaction with 21 mer hairpin DNA possessing N-3 azidoethylthymidine and N-3 propargylthymidine at the 3' and 5'-terminals. Newly synthesized ODNs revealed thermally stable and their structures nearly retained those of non-cross-liked ODNs. This strategy is quite effective to prepare cross-linked circular ODNs.