- NIS/TMSOTf-Promoted Glycosidation of Glycosyl ortho-Hexynylbenzoates for Versatile Synthesis of O-Glycosides and Nucleosides
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Glycosidation plays a pivotal role in the synthesis of O-glycosides and nucleosides that mediate a diverse range of biological processes. However, efficient glycosidation approach for the synthesis of both O-glycosides and nucleosides remains challenging in terms of glycosidation yields, mild reaction conditions, readily available glycosyl donors, and cheap promoters. Here, we report a versatile N-iodosuccinimide/trimethylsilyl triflate (NIS/TMSOTf)-promoted glycosidation approach with glycosyl ortho-hexynylbenzoates as donors for the highly efficient synthesis of O-glycosides and nucleosides. The glycosidation approach highlights the merits of mild reaction conditions, cheap promoters, extremely wide substrate scope, and good to excellent yields. Notably, the glycosidation approach performs very well in the construction of a series of challenging O- and N-glycosidic linkages. The glycosidation approach is then applied to the efficient synthesis of oligosaccharides via the one-pot strategy and the stepwise strategy. On the basis of the isolation and characterization of the departure species derived from the leaving group, a plausible mechanism of NIS/TMSOTf-promoted glycosidation of glycosyl ortho-hexynylbenzoates is proposed.
- Liu, Rongkun,Hua, Qingting,Lou, Qixin,Wang, Jiazhe,Li, Xiaona,Ma, Zhi,Yang, You
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p. 4763 - 4778
(2021/04/06)
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- Inhibition of tyrosyl-DNA phosphodiesterase 1 by lipophilic pyrimidine nucleosides
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Inhibition of DNA repair enzymes tyrosyl-DNA phosphodiesterase 1 and poly(ADP-ribose) polymerases 1 and 2 in the presence of pyrimidine nucleoside derivatives was studied here. New effective Tdp1 inhibitors were found in a series of nucleoside derivatives possessing 2′,3′,5′-tri-O-benzoyl-d-ribofuranose and 5-substituted uracil moieties and have half-maximal inhibitory concentrations (IC50) in the lower micromolar and submicromolar range. 2′,3′,5′-Tri-Obenzoyl- 5-iodouridinemanifested the strongest inhibitory effect on Tdp1 (IC50 = 0.6 μM). Adecrease in the number of benzoic acid residues led to a marked decline in the inhibitory activity, and pyrimidine nucleosides lacking lipophilic groups (uridine, 5-fluorouridine, 5-chlorouridine, 5-bromouridine, 5-iodouridine, and ribothymidine) did not cause noticeable inhibition of Tdp1 (IC50 > 50 μM). No PARP1/2 inhibitors were found among the studied compounds (residual activity in the presence of 1mMsubstances was 50-100%). Several O-benzoylated uridine and cytidine derivatives strengthened the action of topotecan on HeLa cervical cancer cells.
- Chernyshova, Irina A.,Drenichev, Mikhail S.,Dyrkheeva, Nadezhda S.,Ilina, Ekaterina S.,Ivanov, Georgy A.,Lavrik, Olga I.,Mikhailov, Sergey N.,Oslovsky, Vladimir E.,Zakharenko, Alexandra L.
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supporting information
(2020/09/17)
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- Ortho-(1-phenylvinyl)benzoate glycosylation donor, and preparation method and application thereof
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The invention discloses an ortho-(1-phenylvinyl)benzoate glycosylation donor, and a preparation method and an application thereof in a glycosylation reaction. The ortho-(1-phenylvinyl)benzoate glycosylation donor is stable, is easy to prepare and store, and is widely applied to the construction of various oxygen glucosides and nucleoside (nitrogen glucoside) glycosidic bonds. The leaving group ofthe donor is an alkenyl ester, has a high activity, and can be combined with thioglycoside or n-pentenyl ether glucoside through a one-pot glycosylation reaction to synthesize oligosaccharide. The glycosylation reaction conditions are mild, and receptors sensitive to acid and electrophilic reagents can tolerate the glycosylation reaction conditions.
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Paragraph 0193; 0197-0201
(2020/05/01)
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- A solid-supported acidic oxazolium perchlorate as an easy-handling catalyst for the synthesis of modified pyrimidine nucleosides via Vorbrüggen-type N-glycosylation
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A solid-supported acidic oxazolium perchlorate was investigated as a heterogeneous catalyst in N-glycosylation reactions using silylated modified pyrimidines and an acylated ribose or glucose to afford the corresponding pyrimidine nucleosides. This salt is a nonhygroscopic and stable powder whose activity is comparable to that of 2-methyl-5-phenylbenzoxazolium perchlorate. A reaction with this polymer catalyst can be conducted on a gram scale. Reusability of the solid-supported catalyst was also investigated.
- Basu, Nabamita,Oyama, Kin-ichi,Tsukamoto, Masaki
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p. 1921 - 1924
(2017/04/27)
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- Larger laboratory scale synthesis of 5-methyluridine and formal synthesis of its L-enantiomer
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A larger laboratory scale synthesis (>60 g per run) of 5-methyluridine is presented. The critical intermediate 1,2-O-isopropylidene-α-D-ribofuranose was prepared from very cheap D-glucose via D-allose. Its L-enantiomer was obtained from L-arabinose via L-glucose, and also from L-xylose. {figure presented}.
- Thiesen, Luciano J. Hoeltgebaum,Cabral, Nadia,Joselice E Silva, Maria,Bezerra, Gilson,Doboszewski, Bogdan
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p. 249 - 264
(2017/06/19)
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- A general method for N-glycosylation of nucleobases promoted by (p-Tol)2SO/Tf2O with thioglycoside as donor
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Based on a preactivation strategy using the (p-Tol)2SO/Tf2O system, a series of nucleosides were synthesized by coupling various thioglycosides with pyrimidines and purines under mild conditions. High yields and excellent β-stereoselectivities were obtained with either armed or disarmed N-glycosylation donors by tuning the amount of (p-Tol)2SO additive.
- Liu, Guang-Jian,Zhang, Xiao-Tai,Xing, Guo-Wen
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p. 12803 - 12806
(2015/08/06)
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- Propargyl 1,2-orthoesters for a catalytic and stereoselective synthesis of pyrimidine nucleosides
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Pyrimidine nucleosides are synthesized by using propargyl 1,2-orthoesters and Au(III) salt as a catalyst. Strategically positioned 1,2-orthoesters are found to yield only 1,2-trans nucleosides and enable preparation of 2′-OH containing pyrimidine nucleosides. The glycosyl donor employed in this study is stable and easily accessible. The identified high-yielding protocol is mild, diastereoselective, and catalytic.
- Rao, Boddu Venkateswara,Manmode, Sujit,Hotha, Srinivas
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p. 1499 - 1505
(2015/02/19)
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- Antifreeze protein-induced selective crystallization of a new thermodynamically and kinetically less preferred molecular crystal
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The formation of a new, dihydrate crystalline form of 5-methyluridine (m5U) was selectively induced by a protein additive, antifreeze protein (AFP) in a highly efficient manner (in 10-6molar scale, whereas known kinetic additives nee
- Wang, Sen,Wen, Xin,Golen, James A.,Arifin, Josh F.,Rheingold, Arnold L.
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p. 16104 - 16112
(2014/04/03)
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- A Reverse Strategy for synthesis of nucleosides based on n-pentenyl orthoester donors
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Strategically derivatized NPOE glycosyl donors, are able to efficiently glycosylate silylated nucleobases under mild conditions, even as low as -78°C if necessary. Ensuring trans-1,2 glycosylation, thus permitting, unlike classical procedures, a Reverse Strategy for the synthesis of ribonucleosides, where glycosylation occurs late, rather than early, and convergency is optimized.
- Fraser-Reid, Bert,Ganney, Parimala,Ramamurty, Changalvala V. S.,Gomez, Ana M.,Lopez, J. Cristobal
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supporting information
p. 3251 - 3253
(2013/05/08)
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- An efficient approach to the synthesis of nucleosides: Gold(I)-catalyzed N-glycosylation of pyrimidines and purines with glycosyl ortho-alkynyl benzoates
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Persuaded with gold: The title reaction in the presence of [Ph 3PAuNTf2] (Tf=trifluoromethanesulfonyl) led conveniently to the corresponding nucleosides with excellent regioselectivity (see scheme). Even purine derivatives underwent this transformation owing to the mild conditions, which enabled the use of protecting groups that would not usually be compatible with N-glycosylation conditions. Copyright
- Zhang, Qingju,Sun, Jiansong,Zhu, Yugen,Zhang, Fuyi,Yu, Biao
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supporting information; experimental part
p. 4933 - 4936
(2011/06/24)
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- One-flow, multistep synthesis of nucleosides by Bronsted acid-catalyzed glycosylation
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Nucleosides in flow: A general, scalable method of Bronsted acid-catalyzed nucleoside formation is described. Because of the high reaction temperatures readily available to the flow reaction format, mild Bronsted acids, particularly pyridinium triflates, can be used. A one-flow multistep synthesis of unprotected nucleosides is also reported (see scheme).
- Sniady, Adam,Bedore, Matthew W.,Jamison, Timothy F.
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supporting information; experimental part
p. 2155 - 2158
(2011/04/23)
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- An economical synthesis of D- and L-pyrimidine arabinoand ribonucleosides
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The one-step synthesis of several β-D/L-arabino- and ribonucleosides was performed in good yields under reflux or microwave-assisted fusion method. A comparison of the two methods showed that better yields were obtained using the reflux conditions. Copyright Taylor and Francis Group, LLC.
- Lazrek, Hassan B.,Ouzebla, Driss,Faraj, Abdesslem
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experimental part
p. 227 - 234
(2012/04/18)
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- An improved procedure for nucleoside synthesis using glycosyl trifluoroacetimidates as donors
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Using glycosyl trifluoroacetimidates as donors and nitromethane (or acetonitrile) as solvent, silylation and subsequent glycosylation were realized in a 'one-pot' procedure to provide the corresponding nucleosides derivatives in high yields.{A figure is p
- Liao, Jinxi,Sun, Jiansong,Yu, Biao
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experimental part
p. 1034 - 1038
(2009/09/05)
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- Effective synthesis of nucleosides with glycosyl trifluoroacetimidates as donors
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Glycosyl trifluoroacetimidates have been disclosed to be effective glycosyl donors for the synthesis of nucleosides; the present N-glycosylation protocol requires only a catalytic amount of TMSOTf as promoter and proceeds smoothly at room temperature.
- Liao, Jinxi,Sun, Jiansong,Yu, Biao
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p. 5036 - 5038
(2008/12/21)
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- Enhanced solubility and selective benzoylation of nucleosides in novel ionic liquid
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Solubility and benzoylation study of both ribo- and deoxyribonucleosides is reported in a new ionic liquid MoeMIM·TFA; high selectivity for O-benzoylation is achieved.
- Kumar, Vineet,Parmar, Virinder S.,Malhotra, Sanjay V.
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p. 809 - 812
(2007/10/03)
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- Synthesis of a 2′-Se-thymidine phosphoramidite and its incorporation into oligonucleotides for crystal structure study
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(Chemical Equation Presented) To investigate nucleic acids with selenium derivatization for crystallography, we report the first synthesis of 2′-methylseleno-thymidine phosphoramidite and its incorporation into DNAs and RNAs by solid-phase synthesis with over 99% coupling yield. The d(GT SeGTACAC)2 crystal structure was also determined at 1.40 A resolution using Se phasing, revealing that this Se derivatization did not cause significant structure perturbation, consistent with our UV melting study. In addition, we observed that the Se modification largely facilitated the crystallization.
- Sheng, Jia,Jiang, Jiansheng,Salon, Jozef,Huang, Zhen
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p. 749 - 752
(2007/10/03)
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- 'Green' methodology for efficient and selective benzoylation of nucleosides using benzoyl cyanide in an ionic liquid
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Benzoyl cyanide in the ionic liquid 1-methoxyethyl-3-methylimidazolium methanesulfonate has been employed as a 'green' alternative and mild reaction condition protocol to conventional pyridine-benzoyl chloride system for efficient and selective benzoylation of nucleosides (of both the ribo- and deoxyribo-series) at ambient temperatures. The use of benzoyl cyanide-ionic liquid combination has been successfully extended for highly efficient benzoylation of phenols, aromatic amines, benzyl alcohol, aliphatic diols, 3-aminophenol and 2-aminobenzylalcohol, which indicates the versatility of this benzoylating system.
- Prasad, Ashok K.,Kumar, Vineet,Malhotra, Shashwat,Ravikumar, Vasulinga T.,Sanghvi, Yogesh S.,Parmar, Virinder S.
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p. 4467 - 4472
(2007/10/03)
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- Mild, efficient, selective and "green" benzoylation of nucleosides using benzoyl cyanide in ionic liquid
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Use of benzoyl cyanide (BzCN) for benzoylation of nucleosides has been studied, both in pyridine and in ionic liquid. BzCN in 1-methoxyethyl-3- methylimidazolium methanesulfonate as ionic liquid has been found to be a "green" alternative compared to the pyridine-BzCN system. An efficient and selective benzoylation of nucleosides of both, the 2′-deoxy- and the ribo-series at ambient temperature was accomplished. Copyright Taylor & Francis, Inc.
- Prasad, Ashok K.,Kumar, Vineet,Maity, Jyotirmoy,Sanghvi, Yogesh S.,Ravikumar, Vasulinga T.,Parmar, Virinder S.
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p. 747 - 751
(2007/10/03)
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- Benzoyl cyanide: A mild and efficient reagent for benzoylation of nucleosides
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Efficient benzoylation of various nucleosides has been accomplished in pyridine with a catalytic amount of DMAP and benzoyl cyanide under mild conditions.
- Prasad, Ashok K.,Kumar, Vineet,Maity, Jyotirmoy,Wang, Zhiwei,Ravikumar, Vasulinga T.,Sanghvi, Yogesh S.,Parmar, Virinder S.
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p. 935 - 945
(2007/10/03)
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- New acyclonucleosides: Synthesis and anti-HIV activity
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The synthesis of new acyclic nucleosides is described. These syntheses were accomplished by various methods: glycosylation, selective or total deprotection, oxidation/reduction, chlorination or azidation of hydroxyl groups. The compounds were characterized with NMR, mass and IR spectroscopy. Antiviral properties of these compounds were evaluated on HIV-1 infected cell lines. Copyright Taylor & Francis, Inc.
- Hadj-Bouazza, Amel,Zerrouki, Rachida,Krausz, Pierre,Laumond, Geraldine,Aubertin, Anne Marie,Champavier, Yves
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p. 1249 - 1263
(2007/10/03)
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- 2'-deoxy-L-nucleosides
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This invention provides processes for the preparation of compounds having the structure: wherein X and Y are same or different, and H, OH, OR, SH, SR, NH2, NHR′, or NR′R″Z is H, F, Cl, Br, I, CN, or NH2. R is hydrogen, halogen, lower alkyl of C1-C6 or aralkyl, NO2, NH2, NHR′, NR′R″, OH, OR, SH, SR, CN, CONH2, CSNH2, CO2H, CO2R′, CH2CO2H, CH2CO2R′, CH═CHR, CH2CH═CHR, or C═CR. R′ and R″ are same or different, and lower alkyl of C1-C6. R13 is hydrogen, alkyl, acyl, phosphate (monophosphate, diphosphate, triphosphate, or stabilized phosphate) or silyl; and
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Page/Page column 36
(2010/02/11)
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- The synthesis of [(β-D-ribofuranosyloxy)-methyl]nucleosides
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The coupling reaction of acetoxymethoxy ribofuranoside 4 with nucleic acid bases 5a-f to synthesize novel (ribofuranosyloxy)methyl uracil, thymine, cytosine, adenine, guanine derivatives 6a-g respectively in preference to the expected formation of natural nucleosides 2′,3′,5′ -tri-O-benzoyl uridine, methyluridine, cytidine, adenosine and guanosine 7a-g is described. Detailed study of these reactions catalysed by Lewis acids TMSOTf and SnCl4 is described. TMSOTf exhibited selectivity for the formation of ribofuranosyloxy methyl derivatives 6a-g rather than 7a-g. Reason for formation of 6a-g is explained by HSAB principle.
- Mereyala, Hari Babu,Mamidyala, Sreeman Kumar
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p. 655 - 669
(2007/10/03)
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- Facile methods for the synthesis of 5-formylcytidine
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5′-O-Protected 5-methylcytidine 3 was oxidized with Na2S2O8 to give a mixture of the corresponding 5-(hydroxymethyl)- and 5-formylcytidine derivatives, 4 and 5. The hydroxymethyl group of 4 was further oxidized to a formyl group by treatment with ceric(IV) ammonium nitrate (CAN). Alternatively, 2′,3′,5′-O-protected 5-(hydroxymethyl)cytidine 10 was directly oxidized with CAN to give the desired 5-formylcytidine derivative 11. After removal of the protecting groups in each intermediate, 5-formylcytidine (6) was obtained in good yield.
- Abdel Rahman, Adel A.-H.,Wada, Takeshi,Saigo, Kazuhiko
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p. 1061 - 1063
(2007/10/03)
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- Stereocontrolled Syntheses of Deoxyribonucleosides via Photoinduced Electron-Transfer Deoxygenation of Benzoyl-Protected Ribo- and Arabinonucleosides
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The stereocontrolled, de novo syntheses of β-2′-deoxy-, α-2′-deoxy-, β-3′-deoxy-, and β-2′,3′-dideoxyribonucleosides are described. Strategically protected ribose, arabinose, and xylose glycosylation precursors were synthesized bearing C2-esters capable of directing Vorbrueggen glycosylation. The key step is the regioselective deoxygenation of the desired hydroxyl group as either the benzoyl- or 3-(trifluoromethyl)benzoyl derivative. This deoxygenation is accomplished via a photoinduced electron-transfer (PET) mechanism using carbazole derivatives as the photosensitizer. The syntheses of the desired deoxynucleoside generally proceed in three steps from a common, readily available precursor.
- Wang, Zhiwei,Prudhomme, Daniel R.,Buck, Jason R.,Park, Minnie,Rizzo, Carmelo J.
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p. 5969 - 5985
(2007/10/03)
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- Dehydrative glycosylation with activated diphenyl sulfonium reagents. Scope, mode of C(1)-hemiacetal activation, and detection of reactive glycosyl intermediates
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The development of a method for direct dehydrative glycosylations with 1-hydroxyglycosyl donors employing the reagent combination of triflic anhydride and diphenyl sulfoxide is described. The one-pot coupling method is a facile process which is applicable
- Garcia,Gin
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p. 4269 - 4279
(2007/10/03)
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- 5-Substituted UTP derivatives as P2Y2 receptor agonists
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A series of 5-alkyl-substituted UTP derivatives, which had been synthesized previously with a moderate degree of purity, was resynthesized, purified, and characterized. Synthetic and purification procedures were optimized. New spectroscopic data, including 13C- and 31P NMR data, are presented. Phosphorylation reactions yielded a number of side products, such as the 2'-, 3'-, and 5'-monophosphates, the 2',3'-cyclic monophosphates, and the 2',3'-cyclic phosphates of the 5'-triphosphates. Furthermore, raw products were contaminated with inorganic phosphates, including cyclometatriphosphate, phosphate, and pyrophosphate. The uracil nucleotides were investigated for their potency to increase intracellular calcium concentrations by stimulation of P2Y2 receptors (P2Y2R) on NG108- 15 cells, a mouse neuroblastoma x glioma cell line, and in human basal epithelial airway cells, including a cystic fibrosis (CF/T43) cell line. UTP exhibited EC50 values of ca. 1 μM (in NG108-15 cells) and of 0.1 μM (in CF/T43 cells), respectively. 5-Substituted UTP derivatives were agonists at the P2Y2R, but were less potent than UTP. 5-Ethyl-UTP, for example, exhibited an EC50 value of 99 μM at P2Y2R of NG108-15 cells and proved to be a full agonist. With increasing volume of the 5- substituent of UTP derivatives, P2Y2 activity decreased.
- Knoblauch, Bernd H.A.,Mueller, Christa E.,Jaerlebark, Leif,Lawoko, Grace,Kottke, Thomas,Wikstroem, Martin A.,Heilbronn, Edith
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p. 809 - 824
(2007/10/03)
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- Stereocontrolled synthesis of α-2'-deoxyribonucleosides
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A stereocontrolled synthesis of α-2'-deoxynucleosides has been achieved. Our synthetic strategy involves the use of a benzoyl group at the 2-position of arabinose as a directing group for Vorbruggen glycosylation and a deoxygenation precursor.
- Wang, Zhiwei,Rizzo, Carmelo J.
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p. 8177 - 8180
(2007/10/03)
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- 1-(3'-fluoro-2',3'-dideoxy-β-D-ribofuranosyl)-5-substituted pyrimidine nucleosides
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A 2',3'-deoxy-3'-fluoro-pyrimidine nucleoside having the formula: STR1 wherein R1 is OH or NH2 ; R2 is CF3, CH2 CH2 CH3, STR2 CH2 OCH3, CH2 SCH3, CH=CH2 CH=CH--CH3, C CH, C C--CH3 or CH2 --C CH; or a pharmaceutically acceptable salt thereof. These nucleoside analogs exhibit antiviral activity against HIV.
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- Nucleosides. Part LIX. The 2-(4-nitrophenyl)ethylsulfonyl (Npes) group: A new type of protection in nucleoside chemistry
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The 2-(4-nitrophenyl)ethylsulfonyl (npes) group is developed as a new sugar OH-blocking group in the ribonucleoside series. Its cleavage can be performed in a β-eliminating process under aprotic conditions using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the most effective base. Since sulfonates do not show acyl migration, partial protection of 1,2-cis-diol moieties is possible leading to new types of oligonucleotide building blocks. A series of Markiewicz-protected ribonucleosides 1-10 is converted into their 2'-O-[2-(4-nitrophenyl)ethylsulfonyl] derivatives 29-38 in which the 5'-O-Si bond can be cleaved by acid hydrolysis forming 39-45. Subsequent monomethoxytritylation leads to 46-50, and desilylation affords the 5'-O-(monomethoxytrityl)-2'-O-[2-(4-nitrophenyl)ethylsulfonyl]ribonucl eosides 51-55. Acid treatment to remove trityl groups do also not harm the npes group(→ 56-58). Unambiguous syntheses of fully blocked 2'-O-[2-(4-nitrophenyl)ethylsulfonyl]ribonucleosides 96-102 are achieved from the corresponding 3'-O-(tert-butyl)dimethylsilyl derivatives. Furthermore, various base-protected 5'-O-(monomethoxytrityl)- and 5'-O-(dimethoxytrityl)ribonucleosides, i.e. 59-77, are treated directly with 2-(4-nitrophenyl)ethylsulfonyl chloride forming in all cases a mixture of the 2',3'-di-O- and the two possible 2'- and 3'-O-monosulfonates 107-148 which can be separated into the pure components by chromatographic methods. The npes group is more labile towards DBU cleavage than the corresponding base-protecting 2-(4-nitrophenyl)ethyl (npe) and 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) groups allowing selective deblocking which is of great synthetic potential.
- Pfister,Schirmeister,Mohr,Farkas,Stengele,Reiner,Dunkel,Gokhale,Charubala,Pfleiderer
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p. 1705 - 1737
(2007/10/02)
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- A Facile Route to Pyrimidine-Based Nucleoside Olefins: Application to the Synthesis of d4T (Stavudine)
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An efficient synthetic route to nucleoside olefins in the uridine, cytidine, and thymidine series is described which utilizes the Garegg-Samuelsson iodine/triphenylphosphine/imidazole-promoted deoxygenation of the 2',3'-hydroxyl groups as the key step.Cyclopentadiene ketal protection was employed for all the nucleoside 2',3'-hydroxyls to facilitate blocking of the 5'-hydroxyl and the pyrimidine nitrogens with the benzyl or 4-methoxybenzyl (PMB) groups.Deblocking of the cyclopentylidene group followed by olefination of the resulting diols provided protected nucleoside olefins 18-20.Starting with 5-methyluridine 4 and utilizing the 4-methoxybenzyl group for 5',N3 protection, the overall scheme provided the anti-HIV compound d4T (1) after deprotection of the PMB groups.The dibenzylhypoxanthine nucleoside diol 17 derived from inosine gave either unreacted starting material or decomposition products under several sets of conditions.
- Luzzio, Frederick A.,Menes, Michael E.
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p. 7267 - 7272
(2007/10/02)
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- Stereoselective syntheses of β-D-ribonucleosides catalyzed by the combined use of silver salts and diphenyltin sulfide or Lawesson's reagent
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β-D-Ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases by the use of [diphenyltin sulfide/silver salt] or [Lawesson's reagent/silver salt] combined catalyst system under mild conditions.
- Shimomura,Matsutani,Mukaiyama
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p. 3100 - 3106
(2007/10/02)
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- 2'-O,5-dimethyluridine: A total synthesis and single crystal X-ray diffraction study
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A new method for the synthesis of 2'-O,5-dimethyluridine (5) has provided the title compound in a higher yield. Application of a one-pot ribosylation methodology resulted in an efficient, high yield synthesis of 5-methyluridine (ribothymine, 3b). An X-ray diffraction analysis of 5 disclosed the conformation of the sugar moiety of this nucleoside as anti, N(3'-endo), g+.
- Lewis,Revankar,Hogan
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p. 1309 - 1316
(2007/10/02)
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- Catalytic Stereoselective Synthesis of β-Ribonucleosides from Methyl Ribofuranosyl Carbonate and Trimethylsilylated Nucleoside Bases by Combined Use of Silver Salts and Diphenyltin Sulfide
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Catalytic stereoselective synthesis of several ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.
- Mukaiyama, Teruaki,Matsutani, Takafumi,Shimomura, Naoyuki
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p. 1627 - 1630
(2007/10/02)
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- 17O NMR of Nucleosides. 3 - Chemical Shifts of Substituted Uridines and Ribothymidines
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Uridine and ribothymidine derivatives, bearing different substituents at C-5 and enriched (Ca 50percent) with 17O in the O-4 and O-2 carbonyls, have been studied via 17O NMR in both acetonitrile and aqueous solvents.The solvent shift differences between acetonitrile and water at O-4 (30-42 ppm) and O-2 (13-16 ppm) vary significantly from each other, but the chemical shift changes induced by changing the substituent at C-5 correlated well only with the O-4 shifts and the electron-withdrawing ability of the substituent.Examination of the 17O shifts of model compounds reconfirms the predominance of keto tautomers for both carbonyls.The significance of the solvent shifts and substituent shifts are discussed with respect to the electronic structure of the nucleoside base rings, and with respect to the hydrogen-bonding abilities of the carbonyl groups.Other nucleoside derivatives studied include those in which the 17O enrichment is in the ring linking the base to the sugar moiety in a pyrimidine cyclonucleoside, in the sugar hydroxy groups and in the phosphodiester linkage of a highly strained ring system in a nucleoside cyclic monophosphate.
- Schwartz, Herbert M.,MacCoss, Malcolm,Danyluk, Steven S.
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p. 885 - 894
(2007/10/02)
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