title: Synthesis and incorporation of tricyclic-imidazo[5',4':4,5]pyrido[2,3-d]pyrimidine nucleosides into oligonucleotides and their thermal stability.
abstract: We designed and synthesized four novel tricyclicnucleosides 1-4, which have imidazo[5',4':4,5]pyrido[2,3-d]pyrimidine structures, to construct theramallystable, non-natural, DNA duplexes. Both 1:2 and 3:4 possess four complementary hydrogen-bond pairs and are expected to form more stable base-pairs than the naturally occurring Watson-Crick base-pairs when incorporated into oligodeoxynucleotides (ODNs). NMR studies of these base-pairs at the nucleoside level in CDCl3 identified the expected base-pair formation with four hydrogen bonds. We also synthesized several ODNs containing these nucleosides and measured their thermal stability. We found that if several of the novel base-pairs were incorporated on complementary strands, the resulting DNA duplexes had very high thermal stability.
authors.affiliation: Faculty of Pharmaceutical Science, Hokkaido University, Sapporo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kojima
authors.forename: Y
authors.initials: Y
authors.lastname: Ueno
authors.forename: N
authors.initials: N
authors.lastname: Minakawa
authors.forename: A
authors.initials: A
authors.lastname: Matsuda
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004355:Drug Stability; D006860:Hydrogen Bonding; D007202:Indicators and Reagents; D008958:Models, Molecular; D015394:Molecular Structure; D009705:Nucleosides / Q000138:chemical synthesis* / Q000737:chemistry*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D009841:Oligonucleotides / Q000138:chemical synthesis* / Q000737:chemistry*; D011725:Pyridines; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D007202:Indicators and Reagents; D009705:Nucleosides; D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; D011725:Pyridines; D011743:Pyrimidines; D004247:DNA