- Tris(trimethylsilyl)[2H]silane-triethylborane system producing the highly diastereoselective deuteration (> 99:1) of 2'-bromo-2'-deoxy- and 2'-O-phenoxythiocarbonylribonucleosides at 0°C
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Reductive protylation and deuteration reactions using (Me3Si)3SiH- and (Me3Si)3Si2H-Et3B systems were investigated in view of the differences in bond energy and bond length between the Si-H of (Me3Si)3SiH and the Sn-H of Bu3SnH. Higher diastereoselectivity was obtained in comparison with the reactions using the Bu3SnH- and Bu3Sn2H-Et3B systems; the (Me3Si)3SiH system gave remarkable diastereoselectivity of 98.7% at 0°C, whereas the other system required temperatures below -70°C.
- Kawashima, Etsuko,Uchida, Seishiro,Miyahara, Masayoshi,Ishido, Yoshiharu
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Read Online
- 2′-Deoxyriboguanylurea, the primary breakdown product of 5-aza-2′-deoxyribocytidine, is a mutagen, an epimutagen, an inhibitor of DNA methyltransferases and an inducer of 5-azacytidine-type fragile sites
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5-Aza-2′-deoxycytidine (5azaC-dR) has been employed as an inhibitor of DNA methylation, a chemotherapeutic agent, a clastogen, a mutagen, an inducer of fragile sites and a carcinogen. However, its effects are difficult to quantify because it rapidly break
- Lamparska, Katarzyna,Clark, Jarrod,Babilonia, Gail,Bedell, Victoria,Yip, Wesley,Smith, Steven S.
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p. 9788 - 9801
(2013/01/15)
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- Reactivity of nucleosides with a hydroxyl radical in non-aqueous medium
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An experiment was conducted to demonstrate the reactivity of nucleosides with a hydroxyl radical (HO) in non-aqueous medium. Five nucleosides and three purine-derived lesions were taken as targets for HO attack. The reactivity with HO radical was determined by laser flash photolysis (LFP) of N-hydroxypyridine-2-thione (NPT) at 355 nm. Following an established kinetic model, the rate constants for the reaction between HO and the modified nucleobases were determined by using naphthalene as a standard. The values obtained for the silylated 2 -deoxyribonucleosides in acetonitrile are of the same order of magnitude and remarkably lower than diffusion control in this solvent, pointing to a similar reactivity pattern. The result confirmed that the reaction of a hydroxyl radical with 2'-deoxyribonucleosides is in general somewhat slower in acetonitrile than in water.
- Rodriguez-Muniz, Gemma M.,Marin, M. Luisa,Lhiaubet-Vallet, Virginie,Miranda, Miguel A.
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supporting information; experimental part
p. 8024 - 8027
(2012/09/08)
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- Syntheses and oligonucleotide incorporation of nucleoside analogues containing pendant imidazolyl or amino functionalities - The search for sequence-specific artificial ribonucleases
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Oligonucleotide derivatives containing imidazolyl and amino functionalities have been proposed as artificial ribonucleases that might mimic the activities of RNase A but with greater sequence specificity. Such oligonucleotide reagents would have important
- Holmes, Stephen C.,Gait, Michael J.
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p. 5171 - 5183
(2007/10/03)
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- Preparation of deoxynucleosides
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Methods for preparing deoxynucleosides from their corresponding ribonucleosides by forming 3-tert-butylphenoxythiocarbonylderivatives of the ribonucleosides and subsequently effecting radical deoxygenation reactions at the carbon atoms to be deoxygenated.
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Page column 16
(2008/06/13)
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- Synthesis of hapten-phosphoramidites from 2′-deoxyuridine
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A total of 11 novel phosphoramidites, 3a-d, 4a-d and 14a-c were prepared from 2′-deoxyuridine functionalized at 5 and 6-position of the pyrimidine ring with hapten reporter groups, e.g. adamantane, carbazole, dansyl and dabsyl, suitable for use in immunod
- Adamczyk, Maciej,Akireddy, Srinivasa Rao,Mattingly, Phillip G.,Reddy, Rajarathnam E.
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p. 5749 - 5761
(2007/10/03)
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- Hapten-phosphoramidites based on 6-[(2E)-N-(hexyl)prop-2-enamidyl]-2′-deoxyuridine
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Novel hapten-phosphoramidites 11a-c were prepared from 2′-deoxyuridine (2) by functionalization at the 6-position and subsequent conjugation with adamantane, carbazole and dansyl reporter groups in good overall yield.
- Adamczyk, Maciej,Akireddy, Srinivasa Rao,Mattingly, Phillip G,Reddy, Rajarathnam E
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p. 5621 - 5623
(2007/10/03)
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- The PdCl2/R3SiH system for the silylation of nucleosides
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Convenient syntheses of TIPDS-Cl2 and TBDMS-Br from the corresponding hydrides were obtained by using catalytic PdCl2 and CCl4 or CH2Br2, respectively. These systems can be successfully applied in tandem procedures for improved silylation of nucleosides.
- Ferreri,Costantino,Romeo,Chatgilialoglu
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p. 1197 - 1200
(2007/10/03)
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- Radical-Based Deoxygenation of Aliphatic Alcohols via Thioxocarbamate Derivatives
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N-Phenylthioxocarbamates, obtained from the reaction of alcohols with phenyl isothiocyanate in the presence of NaH, were reduced with various silanes such as triethylsilane, triphenylsilane, and tris(trimethylsilyl)silane, as well as tributylstannane under radical conditions to give deoxygenated products of the corresponding alcohols in excellent yields.The reaction was applicable to not only simple aliphatic alcohols but also sugars and nucleosides.Regio- and stereoselective deuteration using deuteriosilanes and deuteriostannane was also examined under the similar conditions.
- Oba, Makoto,Nishiyama, Kozaburo
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p. 10193 - 10200
(2007/10/02)
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- Lithiation of 3',5'-O-(tetraisopropyldisiloxane-1,3-diyl)-2'-deoxyuridine: synthesis of 6-substituted 2'-deoxyuridines
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Synthesis of 6-substituted 2'-deoxyuridines can be effected by lithiation of 3',5'-O-(tetraisopropyldisiloxane-1,3-diyl)-2'-deoxyuridine with LDA followed by the reaction of its lithio derivative with electrophiles. This method provides a general, regiosp
- Tanaka, Hiromichi,Hayakawa, Hiroyuki,Iijima, Shuji,Haraguchi, Kazuhiro,Miyasaka, Tadashi
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p. 861 - 866
(2007/10/02)
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