Synthesis and Characterization of Oligodeoxyribonucleotides Modified with 2鈥?Amino-伪-l-LNA Adenine Monomers: High-Affinity Targeting of Single-Stranded DNA

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• 作者：Nicolai K. Andersen ; Brooke A. Anderson ; Jesper Wengel ; Patrick J. Hrdlicka
• 刊名：Journal of Organic Chemistry
• 出版年：2013
• 出版时间：December 20, 2013
• 年：2013
• 卷：78
• 期：24
• 页码：12690-12702
• 全文大小：538K
• 年卷期：v.78,no.24(December 20, 2013)
• ISSN：1520-6904

文摘

The development of conformationally restricted nucleotide building blocks continues to attract considerable interest because of their successful use within antisense, antigene, and other gene-targeting strategies. Locked nucleic acid (LNA) and its diastereomer 伪-l-LNA are two interesting examples thereof. Oligonucleotides modified with these units display greatly increased affinity toward nucleic acid targets, improved binding specificity, and enhanced enzymatic stability relative to unmodified strands. Here we present the synthesis and biophysical characterization of oligodeoxyribonucleotides (ONs) modified with 2鈥?amino-伪-l-LNA adenine monomers W鈥?b>Z. The synthesis of the target phosphoramidites 1鈥?b>4 is initiated from pentafuranose 5, which upon Vorbr眉ggen glycosylation, O2鈥?deacylation, O2鈥?activation and C2鈥?azide introduction yields nucleoside 8. A one-pot tandem Staudinger/intramolecular nucleophilic substitution converts 8 into 2鈥?amino-伪-l-LNA adenine intermediate 9, which after a series of nontrivial protecting-group manipulations affords key intermediate 15. Subsequent chemoselective N2鈥?functionalization and O3鈥?phosphitylation give targets 1鈥?b>4 in 1鈥?% overall yield over 11 steps from 5. ONs modified with pyrene-functionalized 2鈥?amino-伪-l-LNA adenine monomers X鈥?b>Z display greatly increased affinity toward DNA targets (螖T_m/modification up to +14 掳C). Results from absorption and fluorescence spectroscopy suggest that the duplex stabilization is a result of pyrene intercalation. These characteristics render N2鈥?pyrene-functionalized 2鈥?amino-伪-l-LNAs of considerable interest for DNA-targeting applications.