- Practical synthesis of N-(di-n-butylamino)methylene-protected 2-aminopurine riboside phosphoramidite for RNA solid-phase synthesis
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2-Aminopurine (Ap) is a fluorescent nucleobase analog that is frequently used as structure-sensitive reporter to study the chemical and biophysical properties of nucleic acids. In particular, thermodynamics and kinetics of RNA folding and RNA–ligand binding, as well as RNA catalytic activity are addressable by pursuing the Ap fluorescence signal in response to external stimuli. Site-specific incorporation of Ap into RNA is usually achieved by RNA solid-phase synthesis and requires appropriately functionalized Ap riboside building blocks. Here, we introduce a robust synthetic path toward a 2-aminopurine riboside phosphoramidite whose N2 functionality is masked with the N-(di-n-butylamino)methylene group. This protection is considered advantageous over previously described N-(dimethylamino)methylene or acyl protection patterns needed for the fine-tuned deprotection conditions to achieve large synthetic RNAs. Graphic abstract: [Figure not available: see fulltext.].
- Neuner, Eva,Micura, Ronald
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- High-throughput five minute microwave accelerated glycosylation approach to the synthesis of nucleoside libraries
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The Vorbrueggen glycosylation reaction was adapted into a one-step 5 min/130 °C microwave assisted reaction. Triethanolamine in acetontrile containing 2% water was determined to be optimal for the neutralization of trimethylsilyl inflate allowing for direct MPLC purification of the reaction mixture. When coupled with a NH3/methanol deprotection reaction, a high-throughput method of nucleoside library synthesis was enabled. The method was demonstrated by examining the ribosylation of 48 nitrogen containing heteroaromatic bases that included 25 purines, four pyrazolopyrimidines, two 8-azapurines, one 2-azapurine, two imidazopyridines, two benzimidazoles, three imidazoles, three 1,2,4-triazoles, two pyrimidines, two 3-deazapyrimidines, one quinazolinedione, and one alloxazine. Of these, 32 yielded single regioisomer products, and six resulted in separable mixtures. Seven examples provided inseparable regioisomer mixtures of -two to three compounds (16 nucleosides), and three examples failed to yield isolable products. For the 45 single isomers isolated, the average two-step overall yield ± SD was 26 ± 16%, and the average purity ± SD was 95 ± 6%. A total of 58 different nucleosides were prepared of which 15 had not previously been accessed directly from glycosylation/deprotection of a readily available base.
- Bookser, Brett C.,Raffaele, Nicholas B.
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p. 173 - 179
(2007/10/03)
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- Efficient removal of sugar O-tosyl groups and heterocycle halogens from purine nucleosides with sodium naphthalenide
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Sodium naphthalenide effects removal of 2'-, 3'-, or 5'-O-tosyl groups from the sugar, and 2-, 6-, or 8-halogens from purine nucleosidcs. An improved tosyl protection strategy was developed for the synthesis of 9-(3-deoxy-3-fluoro-β-D-xylofuranosyl)adenine from 2',5'-di-O-tosyladenosine.
- Lewandowska, Elzbieta,Neschadimenko, Vladimir,Wnuk, Stanislaw F.,Robins, Morris J.
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p. 6295 - 6302
(2007/10/03)
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- A novel palladium-catalyzed deoxygenation of guanine O6-arenesulfonates. A practicable synthesis of 2-aminopurine nucleosides and related analogs
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A simple synthesis of 2-aminopurine nucleosides and related derivatives has been accomplished from the corresponding guanine O6-arenesulfonates. Studies towards the determination of optimum conditions for reduction and regioselectivity control are also reported.
- Stimac,Muhic,Kobe
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p. 625 - 636
(2007/10/02)
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- Chemical Synthesis of Oligoribonucleotides Containing 2-Aminopurine: Substrates for the Investigation of Ribozyme Function
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The chemical synthesis of a fully protected ribonucleoside phosphoramidite, containing 2-aminopurine as the base component, and its incorporation into short oligoribonucleotides as substrate for an engineered riboenzyme from Tetrahymena is described.
- Doudna, Jennifer A.,Szostak, Jack W.,Rich, Alexander,Usman, Nassim
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p. 5547 - 5549
(2007/10/02)
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