Oligonucleotide Analogues with Integrated Bases and Backbone : Synthesis and Association of Thiomethylene-Linked UU and AA Dimers

✍ Scribed by Anne Ritter; Bruno Bernet; Andrea Vasella

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: German
• Weight: 730 KB
• Volume: 91
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200890184

✦ Synopsis

Abstract

The thiomethylene‐linked U*[s]U^(^*^)^ dimers 9–14 were synthesized by substitution of the 6‐[(mesyloxy)methyl]uridine 6 by the thiolate derived from the uridine‐5′‐thioacetates 7 and 8 followed by O‐deprotection. Similarly, the thiomethylene‐linked A*[s]A^(^*^)^ dimers 9–14 were obtained from the 8‐(bromomethyl)adenosine 15 and the adenosine‐5′‐thioacetates 16 and 17. The concentration dependence of both HN(3) of the U*[s]U^(^*^)^ dimers 9–14 evidences the formation of linear and cyclic duplexes, and of linear higher associates, C(8 or 6)CH~2~OH and/or C(5′/II)OH groups favouring the formation of cyclic duplexes. The concentration dependence of the chemical shift for both H~2~NC(6) of the A*[s]A^(^*^)^ dimers 18–23 evidences the formation of mainly linear associates. The heteroassociation of U*[s]U^(^*^)^ to A*[s]A^(^*^)^ dimers is stronger than the homoassociation of U*[s]U^(^*^)^ dimers, as evidenced by diluting equimolar mixtures of 11/20 and 13/22. A 1 : 1 stoichiometry of the heteroassociation is evidenced by a Job's plot for 11/20, and by mole ratio plots for 9/18, 10/19, 12/21, 13/22, and 14/23.