DNA and LNA oligonucleotides containing N2′-functionalised derivatives of 2′-amino-2′-deoxyuridine

Synthesis of various N-acylated derivatives of 2′-amino-2′-deoxyuridine is described together with their incorporation into DNA and LNA oligonucleotides using the phosphoramidite approach on an automated DNA synthesizer. The thermal stabilities of duplexes formed by these 2′-amino-DNA-modified DNA or LNA/DNA chimeric strands and complementary DNA or RNA strands have been studied. Introduction of LNA monomers around the functionalised 2′-amino-DNA modifications results in reversal of the affinity-decreasing effect of the latter. This represents a novel general approach for design and synthesis of high-affinity functionalised oligonucleotides for biotechnological or medicinal applications.