title: Synthesis of 5-(1,2,3-triazol-4-yl)-2'-deoxyuridines by a click chemistry approach: stacking of triazoles in the major groove gives increased nucleic acid duplex stability.
abstract: A general protocol for converting alkyl and aryl halides into azides and for converting these in situ into 1,4-disubstituted triazoles was applied with 5-ethynyl-2'-deoxyuridine. This afforded three modified 2'-deoxyuridine analogues with either unsubstituted or 1-phenyl-/1-benzyl-substituted triazoles in their 5-positions. Modelling demonstrates coplanarity of the two heteroaromatic rings, and UV spectroscopy showed the uracil pK(a) values to be almost unchanged. The three nucleosides were introduced into nonamer oligonucleotides by phosphoramidite chemistry. The heteroaromatic triazoles became positioned in the major grooves of the short dsDNA and DNA-RNA duplexes. While single modifications led to decreased duplex stability, the stacking of four consecutive modifications led to enhanced duplex stability, especially for DNA-RNA duplexes. The duplex structures were studied by CD spectroscopy and molecular dynamics simulations, which supported the conjecture that the duplex stabilizing effect is due to efficient stacking of the heteroaromatic triazoles.
authors.affiliation: Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, 5230 Odense M, Denmark.
authors.forename: Petr
authors.initials: P
authors.lastname: Kocalka
authors.forename: Nicolai K
authors.initials: NK
authors.lastname: Andersen
authors.forename: Frank
authors.initials: F
authors.lastname: Jensen
authors.forename: Poul
authors.initials: P
authors.lastname: Nielsen
mesh_terms: D002942:Circular Dichroism; D003857:Deoxyuridine / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009696:Nucleic Acids / Q000737:chemistry*; D013053:Spectrophotometry; D014230:Triazoles / Q000737:chemistry*
chemical_list: D009696:Nucleic Acids; D014230:Triazoles; D003857:Deoxyuridine