2-Azapurine Nucleosides: Synthesis, Properties, and Base Pairing of Oligonucleotides

Authors

  • Simone Budow,

    1. Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, DE-48149 Münster
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  • Frank Seela

    1. Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, DE-48149 Münster
    2. Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie, Universität Osnabrück, Barbarastrasse 7, DE-49069 Osnabrück, (phone: +49 (0)251 53406 500; fax: +49 (0)251 53406 857; homepage: www.seela.net)
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Abstract

This review deals with 2-azapurine (imidazo[4,5-d] [1,2,3]triazine) nucleosides and closely related analogs. Different routes are described to yield the desired target compounds, including a sequence of ring-opening and ring-closure reactions performed on purine nucleosides or direct glycosylation of a 2-azapurine nucleobase with a sugar halide. Further, physical and spectroscopic properties of 2-azapurine nucleosides are discussed, including fluorescence, 13C-NMR data, single-crystal X-ray analyses, and conformation studies on selected compounds; new biological data are presented. The second part of this review is dedicated to oligonucleotides containing 2-azapurines, including building-block (phosphoramidite) preparation and their use in solid-phase oligonucleotide synthesis. Base-pairing properties of 2-azapurine nucleosides as surrogates of canonical constituents of DNA were evaluated.

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