title: Pyrazolo[3,4-d][1,2,3]triazine DNA: synthesis and base pairing of 7-deaza-2,8-diaza-2'-deoxyadenosine.
abstract: 7-deaza-2,8-diaza-2'-deoxyadenosine (4) was synthesized from 8-aza-7-deaza-2'-deoxyadenosine (1) via the 1,N(6)-etheno derivative 5. Ring opening with sodium hydroxide followed by ring closure in the presence of sodium nitrite formed the tricyclic intermediate 5 from which the transiently introduced "etheno" moiety was removed with NBS. Compound 4 was converted to the phosphoramidite 11, which was employed in solid-phase oligonucleotide synthesis. Base pairing studies on 4, incorporated in a 12-mer duplex, showed that this adenine nucleoside analogue forms a strong base pair with dG but not with dT. This novel base pair is as stable as that of the canonical dA-dT pair. As a result of the absence of nitrogen-7 compound 4 is expected to form a face to face base pair with dG.
authors.affiliation: Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany. frank.seela@uni-osnabrueck.de
authors.forename: Frank
authors.initials: F
authors.lastname: Seela
authors.forename: Meike
authors.initials: M
authors.lastname: Lindner
authors.forename: Virginie
authors.initials: V
authors.lastname: Glaçon
authors.forename: Wenqing
authors.initials: W
authors.lastname: Lin
mesh_terms: D020029:Base Pairing; D003500:Cyclization; D004247:DNA / Q000737:chemistry*; D003839:Deoxyadenosines / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D011758:Pyrroles / Q000737:chemistry*; D014227:Triazines / Q000737:chemistry*
chemical_list: C488410:7-deaza-2,8-diaza-2'-deoxyadenosine; D003839:Deoxyadenosines; D009838:Oligodeoxyribonucleotides; D011758:Pyrroles; D014227:Triazines; D004247:DNA