- Antiviral, metabolic, and pharmacokinetic properties of the isomeric dideoxynucleoside 4(S)-(6-amino-9H-purin-9-yl)tetrahydro-2(S)-furanmethanol
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4(S)-(6-Amino-9H-purin-9-yl)tetrahydro-2(s)-furanmethanol (IsoddA) is the most antivirally active member of a novel class of optically active isomeric dideoxynucleosides in which the base has been transposed from the natural 1' position to the 2' position and the absolute configuration is (S,S). IsoddA was active against human immunodeficiency virus type 1 (HIV-1) (strain IIIB), HIV-2 (strain ZY), and HIV-1 clinical isolates. Combinations of the compound with zidovudine (3'-azido-3'-deoxythymidine), 2',3'-dideoxyinosine, or 5- fluoro-2'-deoxy-3'-thiacytidine showed synergistic inhibition of HIV. A moderate reduction of activity was observed with clinical isolates resistant to zidovudine. An IsoddA-resistant virus (eightfold-increased 50% inhibitory concentration) was selected in vitro by repeated passage of HIV-1 (HXB2) in the presence of increasing concentrations of IsoddA. The reverse transcriptase-coding region of the mutant virus contained a single base change resulting in a change at codon 184 from Met to Val. IsoddA was also active against hepatitis B virus (HBV) in vitro; however, it lacked substantial selective activity in an in vivo HBV model. IsoddA was inefficiently phosphorylated in CEM cells; however, the half-life of the triphosphate was 9.4 h, and IsoddATP was a potent inhibitor of HIV-1 reverse transcriptase, with a K(i) of 16 nM. The cytotoxicity 50% inhibitory concentrations of IsoddA were greater than 100 μM for CEM, MOLT-4, IM9, and the HepG2-derived HBV-infected 2.2.15 (subclone P5A) cell lines but were 12 and 11 μM for human granulocyte-macrophage (CFU-GM) and erythroid (BFU-E) progenitor cells, respectively. When given orally to rats and mice, the compound was very well absorbed and rapidly eliminated. However, there was no detectable brain penetration by IsoddA in rats. Catabolic metabolites were not detected, and this is consistent with the observed resistance of the compound to metabolic degradation by adenosine deaminase.
- Nair,St. Clair,Reardon,Krasny,Hazen,Paff Lawrence,Boone,Tisdale,Najera,Dornsife,Averett,Borroto-Esoda,Yale,Zimmerman,Rideout
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Read Online
- CYCLIC DINUCLEOTIDES AS STING AGONISTS
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Disclosed are compounds, compositions and methods for treating of diseases, syndromes, or disorders that are affected by the modulation of STING. Such compounds are represented by Formula (I) as follows: wherein B2,X2, R2a, R2b, R2c, Z-M-Y, Y1-M1Z1, B1, X1, R1a, R1b, R1c are as defined herein.
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Page/Page column 204-206
(2019/07/19)
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- The synthesis of nebularine and its analogs via oxidative desulfuration in aqueous nitric acid
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The synthesis of nebularine and its analogs has been achieved via oxidative desulfuration in H2O for the first time. With 50% HNO3as an oxidant and solvent, 18 products were obtained in good yields (70%–94%). The oxidative desulfuration system could tolerate different functional groups including fluoro, chloro, amino, alkyl, allyl, ribosyl, deoxyribosyl, and arabinofuranosyl groups.More importantly, the drug nebularine could be obtained successfully on a 20 g scale, which made this route more attractive for industrial applications.
- Xia, Ran,Sun, Li-Ping,Qu, Gui-Rong
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supporting information
p. 88 - 91
(2016/12/24)
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- Efficient synthesis of nebularine and vidarabine via dehydrazination of (hetero)aromatics catalyzed by CuSO4 in water
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A simple dehydrazination reaction has been achieved in the presence of a catalytic amount of CuSO4 for the first time. With CuSO4 (2 mol%) as a catalyst and water as a solvent, the dehydrazination products were obtained in good yields (66-95%). Moreover, the drugs nebularine and vidarabine were afforded successfully, and vidarabine could be produced on a 0.923 kg scale, which shows good potential for industrial applications.
- Xia, Ran,Xie, Ming-Sheng,Niu, Hong-Ying,Qu, Gui-Rong,Guo, Hai-Ming
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p. 1077 - 1081
(2014/03/21)
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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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- The nucleoside transport proteins, NupC and NupG, from Escherichia coli: Specific structural motifs necessary for the binding of ligands
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A series of 46 natural nucleosides and analogues (mainly adenosine-based) were tested as inhibitors of [U-14C]uridine uptake by the concentrative, H+-linked nucleoside transport proteins NupC and NupG from Escherichia coli. The two evolutionarily unrelated transporters showed similar but distinct patterns of inhibition, revealing differing selectivities for the different nucleosides and their analogues. Binding of nucleosides to NupG required the presence of hydroxyl groups at each of the C-3′ and C-5′ positions of ribose, while binding to NupC required only the C-3′ hydroxyl substituent. The greater importance of the ribose moiety for binding to NupG is consistent with the evolutionary relationship between this protein and the oligosaccharide: H+ symporter (OHS) subfamily of the major facilitator superfamily (MFS) of transporters. For both proteins the natural α-configuration at C-3′ and the natural β-configuration at C-1′ was mandatory for ligand binding. N-7 in the imidazole ring of adenosine and the amino group at C-6 were found not to be important for binding and both transporters showed flexibility for substitution at C-6/N6; one or both of N-l and N-3 were important for adenosine analogue binding to NupC but significantly less so for binding to NupG. From the different effects of 8-bromoadenosine on the two transporters it appears that adenosine selectively binds to NupC in an anti- rather than a syn-conformation, whereas NupG is less prescriptive. The pattern of inhibition of NupC by differing nucleoside analogues confirmed the functional relationship of the bacterial transporter to members of the human concentrative nucleoside transporter (CNT) family and reaffirmed the use of the bacterial protein as an experimental model for these physiologically and clinically important mammalian proteins. The specificity data for NupG have been used to develop a homology model of the protein's binding site, based on the X-ray crystallographic structure of the disaccharide transporter LacY from E. coli. We have also developed an efficient general protocol for the synthesis of adenosine and three of its analogues, which is illustrated by the synthesis of [1′-13C]adenosine.
- Patching, Simon G.,Baldwin, Stephen A.,Baldwin, Alexander D.,Young, James D.,Gallagher, Maurice P.,Henderson, Peter J. F.,Herbert, Richard B.
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p. 462 - 470
(2007/10/03)
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- Purine nucleoside synthesis from uridine using immobilised Enterobacter gergoviae CECT 875 whole cells
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Biocatalysed purine nucleoside synthesis was carried out using immobilised Enterobacter gergoviae CECT 875. Similar yields (80-95%) in adenosine were obtained with both free and immobilised cells though in the last case a long reaction time was necessary. The immobilised cells can be reused at least for more than 30 times without significant loss of enzymatic activity. The immobilised biocatalyst in agarose is active in the synthesis of unnatural nucleosides.
- Trelles,Fernández,Lewkowicz,Iribarren,Sinisterra
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p. 2605 - 2609
(2007/10/03)
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- Anti-HCV nucleoside derivatives
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The present invention comprises novel and known purine and pyrimidine nucleoside derivatives which have been discovered to be active against hepatitis C virus (HCV). The use of these derivatives for the treatment of HCV infection is claimed as are the novel nucleoside derivatives disclosed herein.
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- Nucleic acid related compounds. 116. Nonaqueous diazotization of aminopurine nucleosides. Mechanistic considerations and efficient procedures with tert-butyl nitrite or sodium nitrite
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Nonaqueous diazotization-dediazoniation of two types of aminopurine nucleoside derivatives has been investigated. Treatment of 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-2-amino-6-chloropurine (1) with SbCl3/CH2Cl2 was examined with benzyltriethylammonium (BTEA) chloride as a soluble halide source and tert-butyl nitrite (TBN) or sodium nitrite as the diazotization reagent. Optimized yields (>80%) of the 2,6-dichloropurine derivative were obtained with SbCl3. Combinations with SbBr3/CH2Br2 gave the 2-bromo-6-chloropurine product (>60%), and SbI3/CH2I2/THF gave the 2-iodo-6-chloropurine derivative (>45%). Antimony trihalide catalysis was highly beneficial. Mixed combinations (SbX3/CH2X′2; X/X′ = Bt/Cl) gave mixtures of 2-(bromo, chloro, and hydro)-6- chloropurine derivatives that were dependent on reaction conditions. Addition of iodoacetic acid (IAA) resulted in diversion of purine radical species into a 2-iodo-6-chloropurine derivative with commensurate loss of other radical-derived products. This allowed evaluation of the efficiency of SbX3-promoted cation-derived dediazoniations relative to radical-derived reactions. Efficient conversions of adenosine, 2′-deoxyadenosine, and related adenine nucleosides into 6-halopurine derivatives of current interest were developed with analogous combinations.
- Francom, Paula,Janeba, Zlatko,Shibuya, Susumu,Robins, Morris J.
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p. 6788 - 6796
(2007/10/03)
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- Synthesis and stability of GNRA-loop analogs
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Nebularinc, 9-(β-D-ribofuranosyl)-9H-purin-2-amine, and inosine phosphoramidites 8, 16, and 17, respectively, were synthesized and incorporated into the GNRA tetraloop at different positions (see Scheme, Table, and Fig. 4). The oligomers were investigated by means of UV and CD spectroscopy to address the question of how the individual base-modified N- nuclcosides contribute to changes in H-bonding and base-stacking interactions within the loop. Several CD spectra are given and compared with each other (Figs 5 and 6). The exchange of the loop sequence in position 4 and 7 results in a distinct change in base stacking. CD-Band shifting allows us to advance the hypothesis that a transition from a GNRA-type towards a UNCG-type base stacking is observed.
- Woerner, Karlheinz,Strube, Thorsten,Engels, Joachim W.
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p. 2094 - 2104
(2007/10/03)
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- A 15N-STUDY ON THE DEAMINATION OF 1-AMINOPURINIUM SALTS WITH AMINES
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Reaction of 1-aminoadenosinium mesitylenesulphonate, 1a, with methanolic ammonia for 10 h at 80 deg C yields adenosine, 7a, and nebularine, 6a.With methanolic methylamine 1a gives 6-methylamino-9-β-D-ribofuranosylpurine, 8a, and adenosine, 7a, respectively.Similar results are obtained with the salt of 1-amino-2',3'-O-isopropylideneadenosine, 1b. 1-Aminoadeninium mesitylenesulphonate, 1c, with methanolic methylamine only yields 6-(methylamino)purine, 8c.In contrast, the mesitylenesulphonate salt of 1,2-diaminopurine, 11, with methanolic methylamine gives only deamination at N1, affording 2-aminopurine, 12.Studies with 15N-labelled methanolic ammonia or 15N-labelled purinium compounds show that in all these reactions, except that of 11, a ring-opening mechanism (ANRORC-mechanism) is involved.
- Kos, Nico J.,Jongejan, Hugo,Plas, Henk C. van der
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p. 369 - 374
(2007/10/02)
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- Syntheses of 9-β-D-Ribofuranosylpurine (Nebularine) and Its Analogues
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9-β-D-Ribofuranosylpurine (nebularine) (9) has been synthesized by two methods. (i) 2,6-Dichloro-2',3',5'-tri-O-benzoyl-9-β-D-ribofuranosylpurine (7) on dehalogenation followed by debenzoylation using methanolic ammonia affords nebularine (9). (ii) 6-Chloro-2',3',5'-tri-O-acetyl-9-β-D-ribofuranosylpurine (18) on dehalogenation followed by deacetylation yields 9.Nebularine analogues , 9-β-D-xylofuranosylpurine (12) and 9-α-L-rhamnopyranosylpurine (15) have also been synthesized from 2,6-dichloro-2',3',5'-tri-O-acetyl-9-β-D-xylofuranosylpurine (10) and 2,6-dichloro-2',3',4'-tri-O-benzoyl-9-α-L-rhamnopyranosylpurine (13).Dehalogenation of 10 and 13 followed by deacetylation and debenzoylation with methanolic ammonia affords 12 and 15 respectively.
- Gupta, P. K.,Bhakuni, D. S.
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p. 534 - 537
(2007/10/02)
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- Utility of Purinyl Radicals in the Synthesis of Base-Modified Nucleosides and Alkylpurines: 6-Amino Group Replacement by H, Cl, Br, and I
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When 9-substituted adenines are treated with n-pentyl nitrite in hydrogen atom donating solvents and the resulting reaction mixtures are warmed and photolyzed with visible light, the corresponding 9-substituted purines are isolated.The conversion apparently involves homolysis of the intermediate 6-diazonium salts or azo compounds to produce purinyl radical intermediates.These purinyl radicals can subsequently abstract hydrogen atoms from solvent molecules.We have utilized our deamination procedure for the direct synthesis of the antitumor antibiotic nebularine from adenosine.When the deaminations of 9-substituted adenines are conducted in dry CCl4, CHBr3, or CH2I2, the corresponding 6-chloro-, 6-bromo-, and 6-iodopurines are isolated in good yields.There appears to be no detectable hydrogen abstraction in competition with halogen abstraction in the cases of CHBr3 and CH2I2 solvents.These transformations provide shortened preparative pathways to intermediates useful in the synthesis of other base-modified purines.Under appropriate reaction conditions, conversions to the 6-6' dimers also may be possible.The type of transformation in this report represents one of the first examples of the use of neutral purinyl radicals in nucleic acid chemistry.
- Nair, Vasu,Richardson, Stephen G.
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p. 3969 - 3974
(2007/10/02)
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