Novel C5-Substituted 2′-Deoxyuridine Derivatives Bearing Amino-Linker Arms: Synthesis, Incorporation into Oligodeoxyribonucleotides, and Their Hybridization Properties
ethylenediamine or tris(2-aminoethyl)amine at the C5-position increase the duplexstability. The amino-linker arm affected the stability of the duplexes depending on the number of aminogroups in the linkerarm and the length of the arm. The linkerarm improved the nuclease resistance at 5′-side phosphodiester linkage of the modified nucleoside in oligodeoxyribonucleotides.
Acridine-modified oligodeoxyribonucleotides (ODNs) at the CS-position of a 2'-deoxyuridine via different lengths of linker arms were synthesized. Reaction of 5-(N-aminoalkyl)carbamoylmethyl-2'-deoxyuridines with 9-phenoxyacridine gave the acridine-modified 2'-deoxyuridines which were incorporated into ODNs. The duplexes containing the acridine-modified strands and their complementary DNA or RNA were thermally more stable than that containing the unmodified strand. Thermal stability of the duplexes of the modified ODNs varied depending on the length of the linker arms.