- Synthesis of the first double-functionalized dinucleotide mRNA cap analogue for its specific labeling
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The modification of various important nucleotide-based molecules (such as nucleotides, RNA, DNA, oligonucleotides) with fluorophores, affinity tags and reactive moieties is of enormous utility for studying their localization, structure and dynamics, as well as diverse biological functions involving their interacting partners. Herein, we report chemical methodology in which the dinucleotide mRNA cap analogue is doubly modified within its second nucleotide. The prepared dinucleotide contains an alkyne at the N2-position of guanine, and levulinic acid within the ribose moiety. Such modifications may be further used for specific labeling of the cap, for instance with a fluorophore that will allow the molecule to be tracked inside the cell and an attachment cell-penetrating peptide that will help to deliver it to the area of interest. Exemplar molecules were attached in order to demonstrate the utility of the newly synthesized cap analogue.
- Piecyk, Karolina,Krynska, Paulina,Kaluzna, Justyna,Jankowska-Anyszka, Marzena
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Read Online
- Photochemical Behavior of 2-Azidopurine Tri-O-Acetylribonucleoside in Aqueous Solution: Unprecedented Transformation into 1-(5′-O-Acetyl-β-D-Ribofuranosyl)-5-[(2-Oxo-1,3,5-Oxadiazocan-4-Ylidene)Amino]-1 H-Imidazole-4-Carbaldehyde
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The photochemical behavior of 2-azidopurine 2′,3′,5′-tri-O-acetylribonucleoside has been investigated in aqueous solution under aerobic and anaerobic conditions. The two major processes under anaerobic irradiation of 2-azidopurine 2′,3′,5′-tri-O-acetylribonucleoside involve unprecedented transformation into 1-(5′-O-acetyl-β-D-ribofuranosyl)-5-[(2-oxo-1,3,5-oxadiazocan-4-ylidene)amino]-1H-imidazole-4-carbaldehyde and photoreduction to respective 2-aminopurine derivative, whereas under aerobic conditions these two processes occur to a much lesser extent and photooxidation to respective 2-nitropurine derivative dominates. The structures of photoproducts formed were confirmed by NMR and high-resolution electrospray ionization mass spectral data.
- Komodziński, Krzysztof,Gdaniec, Zofia,Skalski, Bohdan
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Read Online
- 2-Substituted α,β-Methylene-ADP Derivatives: Potent Competitive Ecto-5′-nucleotidase (CD73) Inhibitors with Variable Binding Modes
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CD73 inhibitors are promising drugs for the (immuno)therapy of cancer. Here, we present the synthesis, structure-activity relationships, and cocrystal structures of novel derivatives of the competitive CD73 inhibitor α,β-methylene-ADP (AOPCP) substituted in the 2-position. Small polar or lipophilic residues increased potency, 2-iodo- and 2-chloro-adenosine-5′-O-[(phosphonomethyl)phosphonic acid] (15, 16) being the most potent inhibitors with Ki values toward human CD73 of 3-6 nM. Subject to the size and nature of the 2-substituent, variable binding modes were observed by X-ray crystallography. Depending on the binding mode, large species differences were found, e.g., 2-piperazinyl-AOPCP (21) was >12-fold less potent against rat CD73 compared to human CD73. This study shows that high CD73 inhibitory potency can be achieved by simply introducing a small substituent into the 2-position of AOPCP without the necessity of additional bulky N6-substituents. Moreover, it provides valuable insights into the binding modes of competitive CD73 inhibitors, representing an excellent basis for drug development.
- Bhattarai, Sanjay,Pippel, Jan,Scaletti, Emma,Idris, Riham,Freundlieb, Marianne,Rolshoven, Georg,Renn, Christian,Lee, Sang-Yong,Abdelrahman, Aliaa,Zimmermann, Herbert,El-Tayeb, Ali,Müller, Christa E.,Str?ter, Norbert
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supporting information
p. 2941 - 2957
(2020/04/10)
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- Synthesis and biological evaluation of a novel C8-pyrrolobenzodiazepine (PBD) adenosine conjugate. A study on the role of the PBD ring in the biological activity of PBD-conjugates
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Here we sought to evaluate the contribution of the PBD unit to the biological activity of PBD-conjugates and, to this end, an adenosine nucleoside was attached to the PBD A-ring C8 position. A convergent approach was successfully adopted for the synthesis of a novel C8-linked pyrrolo(2,1-c)(1,4)benzodiazepine(PBD)-adenosine(ADN) hybrid. The PBD and adenosine (ADN) moieties were synthesized separately and then linked through a pentynyl linker. To our knowledge, this is the first report of a PBD connected to a nucleoside. Surprisingly, the compound showed no cytotoxicity against murine cells and was inactive against Mycobacterium aurum and M. bovis strains and did not bind to guanine-containing DNA sequences, as shown by DNase I footprinting experiments. Molecular dynamics simulations revealed that the PBD-ADN conjugate was poorly accommodated in the DNA minor groove of two DNA sequences containing the AGA-PBD binding motif, with the adenosine moiety of the ligand preventing the covalent binding of the PBD unit to the guanine amino group of the DNA duplex. These interesting findings shed further light on the ability of the substituents attached at the C8 position of PBDs to affect and modulate the biological and biophysical properties of PBD hybrids.
- Bhakta, Sanjib,Brucoli, Federico,Ferguson, Lindsay,Fox, Keith R.,Wells, Geoff
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supporting information
(2020/03/19)
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- Essential Structural Profile of Novel Adenosine Derivatives as Antiplatelet Aggregation Inhibitors Based on 3D-QSAR Analysis Using CoMFA, CoMSIA, and SOMFA
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Abstact: —In this study, comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and the self-organizing molecular field analysis (SOMFA) were performed on a series of novel adenosine derivatives. Significant correlation coefficients (CoMFA, q2 = 0.560, r2 = 0.940, F value = 71.850, and SEE = 0.097; CoMSIA, q2 = 0.528, r2 = 0.943, F value = 29.29 and SEE = 0.108; SOMFA, r2 = 0.615, r2cr= 0.577, F value = 60.797, and SEE = 0.226) were obtained, and the generated models were validated using test sets. By analyzing the corresponding contour maps in detail, new adenosine derivatives with potential efficacy were designed for synthesis in the future.
- Bao, XueFeng,Du, Hongguang,Liu, Guocheng,Lu, Chenghu,Ren, Chaorui,Shunlai, Li
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p. 448 - 457
(2020/06/30)
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- Chemical Synthesis of Oligoribonucleotide (ASL of tRNALys T. brucei) Containing a Recently Discovered Cyclic Form of 2-Methylthio-N6-threonylcarbamoyladenosine (ms2ct6A)
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The synthesis of the protected form of 2-methylthio-N6-threonylcarbamoyl adenosine (ms2t6A) was developed starting from adenosine or guanosine by using the optimized carbamate method and, for the first time, an isocyanate route. The hypermodified nucleoside was subsequently transformed into the protected ms2t6A-phosphoramidite monomer and used in a large-scale synthesis of the precursor 17nt ms2t6A-oligonucleotide (the anticodon stem and loop fragment of tRNALys from T. brucei). Finally, stereochemically secure ms2t6A→ms2ct6A cyclization at the oligonucleotide level efficiently afforded a tRNA fragment bearing the ms2ct6A unit. The applied post-synthetic approach provides two sequentially homologous ms2t6A- and ms2ct6A-oligonucleotides that are suitable for further comparative structure–activity relationship studies.
- Debiec, Katarzyna,Matuszewski, Michal,Podskoczyj, Karolina,Leszczynska, Grazyna,Sochacka, Elzbieta
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supporting information
(2019/08/26)
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- Expedient synthesis of 2-alkylthio-N6-aryladenosines from guanosine
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A general approach for the synthesis of 2-alkylthio-N6-aryladenosine was developed from the commercially available guanosine through the acetyl protection, chlorination, diazotization-alkylthionation, aromatic nucleophilic substitution and deacetylation. Two approaches were designed for the transformation of 2-amino-6-chloroguanosine to 2-alkylthio-N6-aryladenosines but only the one with diazotization-alkylthionation first could afford the target molecules. Both electron-rich and deficient anilines can afford the desired products in moderate to good yield. Finally, under the optimized condition, 20 2-alkylthio-N6-aryladenosines were synthesized, 5 of which exhibit poor antiplatelet aggregation activities.
- Tian, Miao,Chen, Ning,Xu, Fangming,Li, Xiuxiu,Li, Shunlai,Du, Hongguang
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- Absorption Characteristics and Quantum Yields of Singlet Oxygen Generation of Thioguanosine Derivatives
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6-Thioguanine (1a) is considered to be photochemotherapeutic due to its specific characteristics of photosensitivity to UVA light and singlet molecular oxygen generation. To extend its phototherapeutic ability, two related thioguanines, 8-thioguanine (2a) and 6,8-dithioguanine (3a), have been designed and explored. Since the solubility of these thioguanines in dehydrated organic solvents is too poor to study, their triacetyl-protected ribonucleosides, that is, 2′,3′,5′-tri-O-acetyl-6-thioguanosine (1c), 2′,3′,5′-tri-O-acetyl-8-thioguanosine (2c) and 2′,3′,5′-tri-O-acetyl-6,8-dithioguanosine (3c) were prepared and investigated. The absorption maxima of 1c, 2c and 3c in acetonitrile were found at longer wavelengths than that of unthiolated guanosine (4c). Especially, 3c has the longest wavelength for absorption maximum and the highest value in terms of molar absorption coefficient among all thionucleobases and thionucleosides reported. These absorption properties were also well reproduced by quantum chemical calculations. Quantum yields of singlet oxygen generation of 2c and 3c were determined by near-infrared emission measurements to be as large as that of 1c. These results suggest that the newly synthesized thioguanosines, in particular 3c, can be further developed as a potential photosensitive agent for light-induced therapies.
- Miyata, Shoma,Yamada, Takeshi,Isozaki, Tasuku,Sugimura, Hideyuki,Xu, Yao–Zhong,Suzuki, Tadashi
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p. 677 - 684
(2018/04/05)
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- Synthesis, characterization and biological evaluation of purine nucleoside analogues
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We present a convenient route for the synthesis of C6-amino-C5′-N-cyclopropyl carboxamido-C2-alkynylated purine nucleoside analogues 11a–g via Sonogashira coupling reaction. The nine step synthesis is easy to perform, employing commercially available reagents. Compound 9 is used as key intermediate for the synthesis of analogues 11a–g. Synthetic intermediates and final products are appropriately characterized by IR, 1H NMR, 13C NMR and Mass. The modified nucleoside analogues 11a–g is evaluated for in vitro anticancer activity against MDA-MB-231 and Caco-2 cell lines. Screening data reveals that compounds 11b and 11e displayed potent IC50 value of 7.9, 6.8 μg/mL respectively against MDA-MB-231 and of 7.5, 8.3 μg/mL respectively against Caco-2 than the standard drug doxorubicin, thus establishing the potential anti-cancer properties of these newer derivatives.
- Malthum, Shankaraiah,Polkam, Naveen,Allaka, Tejeswara Rao,Chepuri, Kalyani,Anireddy, Jaya Shree
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supporting information
p. 4166 - 4168
(2017/10/13)
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- A New Class of Fluorinated A2A Adenosine Receptor Agonist with Application to Last-Step Enzymatic [18F]Fluorination for PET Imaging
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The A2A adenosine receptor belongs to a family of G-coupled protein receptors that have been subjected to extensive investigation over the last few decades. Due to their prominent role in the biological functions of the heart, lungs, CNS and brain, they have become a target for the treatment of illnesses ranging from cancer immunotherapy to Parkinson's disease. The imaging of such receptors by using positron emission tomography (PET) has also been of interest, potentially providing a valuable tool for analysing and diagnosing various myocardial and neurodegenerative disorders, as well as offering support to drug discovery trials. Reported herein are the design, synthesis and evaluation of two new 5′-fluorodeoxy-adenosine (FDA)-based receptor agonists (FDA-PP1 and FDA-PP2), each substituted at the C-2 position with a terminally functionalised ethynyl unit. The structures enable a synthesis of 18F-labelled analogues by direct, last-step radiosynthesis from chlorinated precursors using the fluorinase enzyme (5′-fluoro-5′-deoxyadenosine synthase), which catalyses a transhalogenation reaction. This delivers a new class of A2A adenosine receptor agonist that can be directly radiolabelled for exploration in PET studies.
- Lowe, Phillip T.,Dall'Angelo, Sergio,Mulder-Krieger, Thea,IJzerman, Adriaan P.,Zanda, Matteo,O'Hagan, David
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p. 2156 - 2164
(2017/10/07)
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- Synthesis, characterization and biological evaluation of C5′-N-cyclopropylcarboxamido-C6-amino-C2-alkynylated purine nucleoside analogues
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In an effort to develop potent antibacterial and anticancer agents, a series of C5′-N-cyclopropylcarboxamido-C6-amino-C2-alkynylated purine nucleoside analogues 11a-g were synthesized through a Sonogashira cross-coupling reaction. The nine-step synthesis is easy to perform, and employs commercially available reagents. 2-Iodo-5′-N-cyclopropylcarboxamidoadenosine (9) was used as the starting intermediate for the synthesis of title derivatives 11a-g. Synthetic intermediates (2–9) and final products (11a-g) were appropriately characterized by IR, 1H NMR, 13C NMR and mass spectroscopy. The synthesized purine nucleoside analogues (11a-g) were evaluated for their in vitro antibacterial activity against two gram-positive and two gram-negative bacteria. They were then tested for cytotoxicity against MDA-MB-231 and Caco-2 cancer cell lines to determine their anti-cancer activity. Among the tested compounds, compounds 11c and 11g showed most potent antibacterial activity against S.aureus and P.aeruginosa bacterial strains. Compounds 11b and 11e displayed considerable IC50s of 7.9 and 6.8 μg/mL, respectively, vs MDA-MB-231 cell lines of 7.5 and 8.3 μg/mL, respectively, against the Caco-2 cell lines.
- Ananda Mohan, Arasavelli,Veera Raghava Sharma, Ganapavarapu,Vidavalur, Siddaiah
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p. 637 - 651
(2017/12/06)
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- Selective Acylation of Nucleosides, Nucleotides, and Glycerol-3-phosphocholine in Water
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A convenient selective synthesis of 2′,3′-di-O-acetyl-nucleotide-5′-phosphates, 2′,3′-di-O-acetyl-nucleotide-5′-triphosphates and 2′,3′,5′-tri-O-acetyl-nucleosides in water has been developed. Furthermore, a long-chain selective glycerol-3-phosphocholine diacylation is elucidated. These reactions are environmentally benign, rapid, high yielding, and the products are readily purified. Importantly, this reaction may indicate a prebiotically plausible reaction pathway for the selective acylation of key metabolites to facilitate their incorporation into protometabolism.
- Fernández-García, Christian,Powner, Matthew W.
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supporting information
p. 78 - 83
(2016/12/26)
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- Tautomerism in 8-Nitroguanosine Studied by NMR and Theoretical Calculations
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The guanine base in DNA, due to its low oxidation potential, is particularly sensitive to chemical modifications. A large number of guanine lesions have been characterized and studied in some detail due to their relationship with tissue inflammations. Nevertheless, one example of these lesions is the formation of 8-nitro-guanosine, but the NMR data of this compound was only partially interpreted. A comprehensive study of the two possible tautomeric forms, through a detailed characterization of this compound, has implications for its base pairing properties. The target compound was obtained through a synthetic sequence of five steps, where all intermediates were fully characterized using spectral data. The analysis of the two tautomers was then evaluated through NMR spectroscopy and theoretical calculations of the chemical shifts and NH coupling constants, which were also compared with the data from guanosine.
- Barbosa, Thaís M.,Rittner, Roberto,Alexander, Katie,Cosstick, Richard,Abraham, Raymond J.
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- Synthesis of 8-alkoxy-6-alkylamino-2-alkylthiopurine nucleosides with a straightforward multiple-functionalization strategy
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A straight forward strategy to synthesize purine nucleosides with multiple functionalization on 2-, 6-, and 8-positions has been developed successfully, which provides a series of 8-alkoxy-6-alkylamino-2-alkylthiopurine nucleosides in moderate to good yields for further biological and medical activity screening.
- Du, Hongguang,Sun, Xiaoyang,Yu, Mingwu,Tian, Miao,Li, Shunlai,Wang, Zhiqian
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supporting information
p. 2949 - 2953
(2016/07/06)
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- Discovery of Leucyladenylate Sulfamates as Novel Leucyl-tRNA Synthetase (LRS)-Targeted Mammalian Target of Rapamycin Complex 1 (mTORC1) Inhibitors
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Recent studies indicate that LRS may act as a leucine sensor for the mTORC1 pathway, potentially providing an alternative strategy to overcome rapamycin resistance in cancer treatments. In this study, we developed leucyladenylate sulfamate derivatives as LRS-targeted mTORC1 inhibitors. Compound 18 selectively inhibited LRS-mediated mTORC1 activation and exerted specific cytotoxicity against colon cancer cells with a hyperactive mTORC1, suggesting that 18 may offer a novel treatment option for human colorectal cancer.
- Yoon, Suyoung,Kim, Jong Hyun,Kim, Sung-Eun,Kim, Changhoon,Tran, Phuong-Thao,Ann, Jihyae,Koh, Yura,Jang, Jayun,Kim, Sungmin,Moon, Hee-Sun,Kim, Won Kyung,Lee, Sangkook,Lee, Jiyoun,Kim, Sunghoon,Lee, Jeewoo
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p. 10322 - 10328
(2016/12/07)
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- How to find the optimal partner - Studies of snurportin 1 interactions with U snRNA 5′ TMG-cap analogues containing modified 2-amino group of 7-methylguanosine
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Snurportin 1 is an adaptor protein that mediates the active nuclear import of uridine-rich small nuclear RNAs (U snRNA) by the importin-β receptor pathway. Its cellular activity influences the overall transport yield of small ribonucleoprotein complexes containing N2,N2,7-trimethylguanosine (TMG) capped U snRNA. So far little is still known about structural requirements related to molecular recognition of the trimethylguanosine moiety by snurportin in solution. Since these interactions are of a great biomedical importance, we synthesized a series of new 7-methylguanosine cap analogues with extended substituents at the exocyclic 2-amino group to gain a deeper insight into how the TMG-cap is adapted into the snurportin cap-binding pocket. Prepared chemical tools were applied in binding assays using emission spectroscopy. Surprisingly, our results revealed strict selectivity of snurportin towards the TMG-cap structure that relied mainly on its structural stiffness and compactness.
- Piecyk, Karolina,Niedzwiecka, Anna,Ferenc-Mrozek, Aleksandra,Lukaszewicz, Maciej,Darzynkiewicz, Edward,Jankowska-Anyszka, Marzena
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supporting information
p. 4660 - 4668
(2015/08/03)
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- Light-Triggered RNA Annealing by an RNA Chaperone
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Non-coding antisense RNAs regulate bacterial genes in response to nutrition or environmental stress, and can be engineered for artificial gene control. The RNA chaperone Hfq accelerates antisense pairing between non-coding RNAs and their mRNA targets, by a mechanism still unknown. We used a photocaged guanosine derivative in an RNA oligonucleotide to temporally control Hfq catalyzed annealing. Using a fluorescent molecular beacon as a reporter, we observed RNA duplex formation within 15 s following irradiation (3 s) of photocaged RNA complexed with Hfq. The results showed that the Hfq chaperone directly stabilizes the initiation of RNA base pairs, and suggests a strategy for light-activated control of gene expression by non-coding RNAs.
- Panja, Subrata,Paul, Rakesh,Greenberg, Marc M.,Woodson, Sarah A.
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supporting information
p. 7281 - 7284
(2015/06/30)
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- Synthesis and evaluation of 2-ethynyl-adenosine-5′-triphosphate as a chemical reporter for protein AMPylation
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Protein AMPylation is a posttranslational modification (PTM) defined as the transfer of an adenosine monophosphate (AMP) from adenosine triphosphate (ATP) to a hydroxyl side-chain of a protein substrate. One recently reported AMPylator enzyme, Vibrio outer protein S (VopS), plays a role in pathogenesis by AMPylation of Rho GTPases, which disrupts crucial signaling pathways, leading to eventual cell death. Given the resurgent interest in this modification, there is a critical need for chemical tools that better facilitate the study of AMPylation and the enzymes responsible for this modification. Herein we report the synthesis of 2-ethynyl-adenosine-5′-triphosphate (2eATP) and its utilization as a non-radioactive chemical reporter for protein AMPylation.
- Creech, Christa,Kanaujia, Mukul,Causey, Corey P.
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p. 8550 - 8555
(2015/08/06)
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- Solid-phase synthesis and hybrization behavior of partially 2′/3′-O-acetylated RNA oligonucleotides
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Synthesis of partially 2′/3′-O-acetylated oligoribonucleotides has been accomplished by using a 2′/3′-O-acetyl orthogonal protecting group strategy in which non-nucleophilic strong-base (DBU) labile nucleobase protecting groups and a UV-light cleavable linker were used. Strong-base stability of the photolabile linker allowed on-column nucleobase and phosphate deprotection, followed by a mild cleavage of the acetylated oligonucleotides from the solid support with UV light. Two 17nt oligonucleotides, which were synthesized possessing one specific internal 2′- or 3′-acetyl group, were used as synthetic standards in a recent report from this laboratory detailing the prebiotically plausible ligation of RNA oligonucleotides. In order to further investigate the effect of 2′/3′-O-acetyl groups on the stability of RNA duplex structure, two complementary bis-acetylated RNA oligonucleotides were also expediently obtained with the newly developed protocols. UV melting curves of 2′-O-acetylated RNA duplexes showed a consistent ~3.1 °C decrease in Tm per 2′-O-acetyl group.
- Xu, Jianfeng,Duffy, Colm D.,Chan, Christopher K. W.,Sutherland, John D.
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p. 3311 - 3326
(2014/05/06)
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- A localized tolerance in the substrate specificity of the fluorinase enzyme enables "last-step" 18F fluorination of a RGD peptide under ambient aqueous conditions
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A strategy for last-step 18F fluorination of bioconjugated peptides is reported that exploits an "Achilles heel" in the substrate specificity of the fluorinase enzyme. An acetylene functionality at the C-2 position of the adenosine substrate projects from the active site into the solvent. The fluorinase catalyzes a transhalogenation of 5-chlorodeoxy-2- ethynyladenosine (ClDEA) to 5-fluorodeoxy-2-ethynyladenosine (FDEA). Extending a polyethylene glycol linker from the terminus of the acetylene allows the presentation of bioconjugation cargo to the enzyme for 18F labelling. The method uses an aqueous solution (H218O) of [ 18F]fluoride generated by the cyclotron and has the capacity to isotopically label peptides of choice for positron emission tomography (PET).
- Thompson, Stephen,Zhang, Qingzhi,Onega, Mayca,McMahon, Stephen,Fleming, Ian,Ashworth, Sharon,Naismith, James H.,Passchier, Jan,O'Hagan, David
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supporting information
p. 8913 - 8918
(2014/10/15)
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- Ribofuranosyl Purine Compounds, Methods for Preparing the Same and Use Thereof
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The present invention relates to the compounds of the formulae (I) and (I-1) and the process for preparing the same, uses of the compounds for the treatment of diseases associated with platelet aggregation and in the manufacture of a medicament for the treatment of diseases associated with platelet aggregation, and relates to a pharmaceutical composition and a pharmaceutical formulation containing the compounds, wherein the definitions of R1, R2, R3 and R2a in the formulae are the same as those in the description.
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Paragraph 0065; 0066
(2014/02/15)
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- Photochemistry of 6-amino-2-azido, 2-amino-6-azido and 2,6-diazido analogues of purine ribonucleosides in aqueous solutions
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The photochemistry of 6-amino-2-azidopurine, 2-amino-6-azidopurine and 2,6-diazidopurine ribonucleosides has been investigated in aqueous solutions under aerobic and anaerobic conditions. Near UV irradiation of 6-amino-2-azido-9-(2′,3′,5′-tri-O-acetyl-β-d- ribofuranosyl)purine and 2-amino-6-azido-9-(2′,3′,5′-tri-O- acetyl-β-d-ribofuranosyl)purine in the presence of oxygen leads to efficient formation of 6-amino-2-nitro-9-(2′,3′,5′-tri-O- acetyl-β-d-ribofuranosyl)purine and 2-amino-6-nitro-9-(2′,3′, 5′-tri-O-acetyl-β-d-ribofuranosyl)purine. Under anaerobic conditions, both azidopurine ribonucleosides preferentially undergo photoreduction to 2,6-diamino-9-(2′,3′,5′-tri-O-acetyl-β-d-ribofuranosyl) purine. The structures of the photoproducts formed were confirmed by UV, NMR and HR ESI-TOF MS spectral data. The photoproducts observed in this study for the aminoazidopurines are distinctly different from those observed previously for 6-azidopurine. When no amino group is present, the photochemistry of 6-azidopurine leads to the formation of a 1,3,5-triazepinone nucleoside. The energetics of the 6-nitreno moiety along both oxidation and ring expansion pathways was calculated using the nudged elastic band (NEB) method based on density functional theory (DFT) using DMol3. The role of the 2-amino group in regulating the competition between these pathways was elucidated in order to explain how the striking difference in reactivity under irradiation arises from the greater spin density on the 6-nitreno-9-methyl-9H-purin-2-amine, which essentially eliminates the barrier to oxidation observed in 6-nitreno-9-methyl- 9H-purine. Finally, the importance of tetrazolyl intermediates for the photochemical activation of azide bond cleavage to release N2 and form the 6-nitreno group was also corroborated using the DFT methods. The Royal Society of Chemistry and Owner Societies.
- Komodzinski, Krzysztof,Lepczynska, Jolanta,Gdaniec, Zofia,Bartolotti, Libero,Delley, Bernard,Franzen, Stefan,Skalski, Bohdan
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p. 563 - 573
(2014/03/21)
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- Synthesis and structure-activity relationships of 2-hydrazinyladenosine derivatives as A2A adenosine receptor ligands
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A series of 2-hydrazinyladenosine derivatives was synthesized and investigated in radioligand binding studies for their affinity at the adenosine receptor subtypes with the goal to obtain potent and A2AAR selective agonists and to explore the structure-activity relationships of this class of compounds at A2AAR. Modifications included introduction of a second sugar moiety at position 2 of adenosine to form new bis-sugar nucleosides and/or modifications of the 2-position linker in different ways. The performed modifications were found to produce compounds with relatively high A 2AAR affinity and very high selectivity toward A2AAR. The most potent bis-sugar nucleoside was obtained with the D-galactose derivative 16 which exhibited a Ki value of 329 nM at A2AAR with marked selectivity against the other AR subtypes. In another set of compounds, compound 3 was modified via replacement of its cyclic structure with mono- and disubstituted phenyl moieties and the resulting hydrazones 10-14 were found to have low nanomolar affinity for A2AAR. In addition to 3, compounds 10, 11 and 13 have been identified as the most potent compounds in the present series with Ki values of 16.1, 24.4, and 12.0 nM, respectively, at rat A2AAR. Species differences were tested and found to exist in different rates. Functional properties of the most potent compounds 10, 11, 13 and 16 were assessed showing that the compounds acted as agonists at A 2AAR.
- El-Tayeb, Ali,Gollos, Sabrina
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supporting information
p. 436 - 447
(2013/03/14)
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- RIBOFURANOSYL PURINE COMPOUND, PREPARATION METHOD THEREFOR, AND USE THEREOF
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The present invention relates to the compounds of the formulae (I) and (I-1) and the process for preparing the same, uses of the compounds for the treatment of diseases associated with platelet aggregation and in the manufacture of a medicament for the treatment of diseases associated with platelet aggregation, and relates to a pharmaceutical composition and a pharmaceutical formulation containing the compounds, wherein the definitions of R1, R2, R3 and R2a in the formulae are the same as those in the description.
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Paragraph 0048
(2014/01/07)
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- Synthesis of N2-modified 7-methylguanosine 5′- monophosphates as nematode translation inhibitors
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Preparative scale synthesis of 14 new N2-modified mononucleotide 5′ mRNA cap analogues was achieved. The key step involved use of an SNAr reaction with protected 2-fluoro inosine and various primary and secondary amines. The derivatives were tested in a parasitic nematode, Ascaris suum, cell-free system as translation inhibitors. The most effective compound with IC50 ~0.9 μM was a N2-p-metoxybenzyl-7- methylguanosine-5′-monophosphate 35.
- Piecyk, Karolina,Davis, Richard E.,Jankowska-Anyszka, Marzena
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experimental part
p. 4781 - 4789
(2012/08/29)
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- Synthesis of N6-alkyl(aryl)-2-alkyl(aryl)thioadenosines as antiplatelet agents
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A series of novel N6-alkyl(aryl)-2-alkyl(aryl)thioadenosines were synthesized, and their human antiplatelet aggregation activities were evaluated by the stimulation of adenosine 5′-diphosphate (ADP). Some of these compounds showed strong activity, among which compound 5b11 displayed the highest activity with an IC50 value of 29 ± 3 μM. Furthermore, five compounds were tested against arachidonic acid (AA)-induced human platelet aggregation. The results showed that compound 5b10 exhibited the highest activity with an IC50 value of 3 ± 2 μM. The adenosine derivatives substituted with a phenethyl group at the N6 position and a methylthio or ethylthio group at the C-2 position displayed high antiplatelet aggregation activity.
- Liu, Guocheng,Xu, Jiaxi,Chen, Ning,Zhang, Si,Ding, Zhongren,Du, Hongguang
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supporting information; experimental part
p. 114 - 123
(2012/08/28)
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- A modified guanosine phosphoramidite for click functionalization of RNA on the sugar edge
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A propargyl containing guanosine phosphoramidite was synthesized and incorporated into siRNA, enabling click-ligation with an azido fluorophore onto the nucleobase sugar edge. Duplex stability was not affected by labeling at this new site, which allowed deconvolution of the effects of label, structure and attachment site on RNAi activity.
- Seidu-Larry, Salifu,Krieg, Bettina,Hirsch, Markus,Helm, Mark,Domingo, Olwen
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supporting information
p. 11014 - 11016
(2013/01/15)
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- Synthesis of 13C- and 14C-labeled dinucleotide mRNA cap analogues for structural and biochemical studies
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Herein we describe the first simple and short method for specific labeling of mono- and trimethylated dinucleotide mRNA cap analogues with 13C and 14C isotopes. The labels were introduced within the cap structures either at the N7 for monomethylguanosine cap or N7 and N2 position for trimethylguanosine cap. The compounds designed for structural and biochemical studies will be useful tools for better understanding the role of the mRNA cap structures in pre-mRNA splicing, nucleocytoplasmic transport, translation initiation and mRNA degradation.
- Piecyk, Karolina,Davis, Richard E.,Jankowska-Anyszka, Marzena
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scheme or table
p. 4391 - 4395
(2012/09/21)
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- Evidence for the existence of a specific gprotein-coupled receptor activated by guanosine
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Guanosine, released extracellularly from neurons and glial cells, plays important roles in the central nervous system, including neuroprotection. The innovative DELFIA Eu-GTP binding assay was optimized for characterization of the putative guanosine receptor binding site at rat brain membranes by using a series of novel and known guanosine derivatives. These nucleosides were prepared by modifying the purine and sugar moieties of guanosine at the 6- and 5'-positions, respectively. Results of these experiments prove that guanosine, 6-thioguanosine, and their derivatives activate a Gprotein-coupled receptor that is different from the well-characterized adenosine receptors. Catching the elusive guanosine receptor: The innovative DELFIA Eu-GTP binding assay was applied to characterize the guanosine binding site by using novel and known guanosine derivatives. Some of the tested compounds, which proved to be full agonists with EC50 values in the low nanomolar range, could be useful tools for further characterization of the putative guanosine receptor.
- Volpini, Rosaria,Marucci, Gabriella,Buccioni, Michela,DalBen, Diego,Lambertucci, Catia,Lammi, Carmen,Mishra, Ram C.,Thomas, Ajiroghene,Cristalli, Gloria
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scheme or table
p. 1074 - 1080
(2012/01/06)
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- Design, synthesis and characterisation of guanosine-based amphiphiles
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A small library of sugar-modified guanosine derivatives has been prepared, starting from a common intermediate, fully protected on the nucleobase. Insertion of myristoyl chains and of diverse hydrophilic groups, such as an oligoethylene glycol, an amino acid or a disaccharide chain, connected through in vivo reversible ester linkages, or of a charged functional group provided different examples of amphiphilic guanosine analogues, named G1-G7 herein. All of the sugar-modified derivatives were positive in the potassium picrate test, showing an ability to form G-tetrads. CD spectra demonstrated that, as dilute solutions in CHCl3, distinctive G-quadruplex systems may be formed, with spatial organisations dependent upon the structural modifications. Two compounds, G1 and G2, proved to be good low-molecular-weight organogelators in polar organic solvents, such as methanol, ethanol and acetonitrile. Ion transportation experiments through phospholipid bilayers were carried out to evaluate their ability to mediate H+ transportation, with G5 showing the highest activity within the investigated series. Moreover, G3 and G5 exhibited a significant cytotoxic profile against human MCF-7 cancer cells in in vitro bioassays.
- Simeone, Luca,Milano, Domenico,De Napoli, Lorenzo,Irace, Carlo,Di Pascale, Antonio,Boccalon, Mariangela,Tecilla, Paolo,Montesarchio, Daniela
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experimental part
p. 13854 - 13865
(2012/01/15)
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- Non-Natural Peptides as Models for the Development of Antibiotics
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Described herein are methods of screening one of the RNA hairpins in the small ribosomal subunit of bacteria to identify peptides that bind to it. The RNA hairpin target may be the 970 loop (aka helix 31 (h31)) or a modified version thereof. The identified peptides may inhibit protein synthesis and, therefore, may be used as a model for new antibiotics.
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- Synthesis and characterization of modified nucleotides in the 970 hairpin loop of Escherichia coli 16S ribosomal RNA
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The synthesis of the 6-O-DPC-2-N-methylguanosine (m2G) nucleoside and the corresponding 5′-O-DMT-2′-O-TOM-protected 6-O-DPC-2-N-methylguanosine phosphoramidite is reported [DPC, diphenyl carbamoyl; DMT, 4,4′-dimethoxytrityl; TOM, [(triisopropylsilyl)oxy]methyl]. The availability of the phosphoramidite allows for syntheses of hairpin RNAs with site-selective incorporation of 2-N-methylguanosine modification. Four 18-nt hairpin RNA analogues representing the 970-loop region (helix 31 or h31; U960-A975) of Escherichia coli 16S rRNA were synthesized with and without modifications in the loop region. Subsequently, stabilities and conformations of the singly and doubly modified RNAs were examined and compared with the corresponding unmodified RNA. Thermodynamic parameters and circular dichroism spectra are presented for the four helix 31 RNA analogues. Surprisingly, methylations in the loop region of helix 31 slightly destabilize the hairpin, which may have subtle effects on ribosome function. The hairpin construct is suitable for future ligand-binding experiments.
- Abeydeera, N. Dinuka,Chow, Christine S.
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scheme or table
p. 5887 - 5893
(2009/12/09)
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- RNA as scaffold for pyrene excited complexes
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Synthesis and spectral properties of 1-ethynylpyrene base modified RNA are reported. The fluorophore attached to the 2-position of adenosine is directed into the easily accessible minor groove in RNA. Through an intermolecular interaction of the pyrene residues in twofold labelled RNA, single and double strands can be distinguished by their fluorescence maxima around 450 and 480 nm, respectively. This behaviour allows the kinetic investigation of RNA hybridisation and folding by fluorescence spectroscopy.
- Gruenewald, Christian,Kwon, Taewoo,Piton, Nelly,Foerster, Ute,Wachtveitl, Josef,Engels, Joachim W.
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- COMPOUND HAVING INHIBITORY ACTIVITY ON A RHO-GTPASE CELL PROTEIN, A PROCESS FOR OBTAINING THE SAME, PHARMACEUTICAL COMPOSITIONS COMPRISION THEREOF AND A METHOD FOR THE TREATMENT OF A RHO-GTPASE CELL PROTEIN-MEDIATED CONDITION
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The present invention relates to a compound having inhibitory activity on a Rho-GTPase cell protein, the compound having the formula I (Formula I ) wherein A is selected from N and N-H, R1 is selected from H and NHR3, R2 is selected from NHR4, OR4, O and halogen, R3 is selected from H and -COR5, R4 is selected from H, a C1-C6 alkyl and a substituted or unsubstituted phenyl, R5 is selected from a C1-C12 alkyl and a substituted or unsubstituted phenyl, R6 is selected from H, -COR5, -CO2R5, -PR7R8 and -PR7R8OPR7R8R8R7, R7 is selected from O and S, R8 is selected from H, OR4 and OSATE (-OCH2CH2SCOR5), and wherein each represents a single bond or a double bond, provided that when one of them is a double bond the other one is a single bond, and pharmaceutically acceptable salts and derivatives thereof. In particular, the compounds of the invention may be used as antitumor agents the action of which interfere with the signaling pathways normally involved in tumor development processes. The invention also relates to processes for obtaining of compounds having inhibitory activity of a Rho- GTPase cell protein, to the pharmaceutical compositions thereof and to the therapeutic methods comprising the use of said compounds and compositions.
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Page/Page column 25-26
(2008/12/05)
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- IMPDH as a biological probe for RNA antiviral drug discovery: Synthesis, enzymology, molecular docking, and antiviral activity of new ribonucleosides with surrogate bases
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Our interest in the discovery of molecules with antiviral activity against RNA viruses led us to the design of ribonucleosides with surrogate bases with the intent of using inhibition of inosine monophosphate dehydrogenase (IMPDH) as a probe for antiviral drug discovery. A general methodology for the preparation of these compounds is discussed. Kinetic parameters of the inhibition studies with IMPDH, which were carried out spectrophotometrically by monitoring the formation of NADH, are given. Antiviral information and correlation of activity with IMPDH inhibition are discussed. Copyright Taylor & Francis Group, LLC.
- Nair, Vasu,Ma, Xiaohui,Shu, Qingning,Zhang, Fan,Uchil, Vinod,Cherukupalli, Govardhan R.
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p. 651 - 654
(2008/09/17)
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- Pyridine-free and solvent-free acetylation of nucleosides promoted by molecular sieves
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A practical method for the acetylation of purine and pyrimidine nucleosides employing a combination of acetic anhydride and potassium-exchanged molecular sieves is described. Besides the high yields obtained for the acylated nucleosides, the procedure is simple, inexpensive and environmentally benign, avoiding the use of pyridine or co-solvents as additives. Georg Thieme Verlag Stuttgart.
- Sá, Marcus Mandolesi,Meier, Lidiane
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p. 3474 - 3478
(2007/10/03)
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- Practical syntheses of penciclovir and famciclovir from N2-acetyl-7-benzylguanine
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We have established practical methods for the synthesis of penciclovir (PCV) and famciclovir (FCV) from readily available guanosine via N2-acetyl-7-benzylguanine. The alkylation of N2-acetyl-7-benzylguanine proceeded selectively at the N9 position to give the desired alkylated product in good yield in salt form. After conventional catalytic hydrogenolysis of the benzyl group and hydrolysis of the resulting acetate, pure PCV was obtained without the need for chromatography. As a side chain precursor, the mesylate was selected rather than a halide since the corresponding halides gave several impurities under the same reaction conditions. Two procedures for the synthesis of FCV from PCV and a derivative are also reported.
- Torii, Takayoshi,Shiragami, Hiroshi,Yamashita, Keizo,Suzuki, Yumiko,Hijiya, Toyoto,Kashiwagi, Tatsuki,Izawa, Kunisuke
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p. 5709 - 5716
(2007/10/03)
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- Kinetics and mechanism of the defluorination of 8-fluoropurine nucleosides in basic and acidic media
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For investigating the stability of C(8)-fluorine bond in 8-fluoropurine nucleosides some protected 8-fluoroguanosine, 8-fluoroinosine and 8-fluoroadenosine derivatives were prepared by direct fluorination of acetyl-protected purine nucleosides with elemental fluorine in solvents such as chloroform, acetonitrile and nitromethane. Fluorination reactions conducted in chloroform medium gave better yields of 8-fluoropurines. The fluorination yields were slightly lower when acetonitrile or nitromethane was used as solvent, but the product purification was found to be much easier. When the synthesized, protected fluoronucleosides were subjected to standard basic (NH3 in methanol or 2-propanol) and acidic (HCl in methanol) deprotection conditions relevant to nucleoside chemistry, an efficient defluorination reaction took place. The kinetics of these defluorination reactions were conveniently followed, under pseudo-first-order reaction conditions, using 19F NMR spectroscopy. 1H NMR, LC-MS and mass spectroscopy identified the products of the kinetic reaction mixtures. The defluorination reaction rate constants (kobs) in basic media depended upon the electron density at C(8) while the kobs data in acidic medium were determined by the pKa of N7. An addition-elimination based mechanism (SNAr) has been proposed for the defluorination reactions of these 8-fluoropurine nucleosides.
- Liu, Jie,Barrio, Jorge R.,Satyamurthy, Nagichettiar
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p. 1175 - 1187
(2008/12/20)
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- A quadruply hydrogen bonded heterocomplex displaying high-fidelity recognition
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An exceptionally strong quadruply hydrogen-bonded complex is formed between 2,7-diamido-1,8-naphthyridine 3 (DAN) and the butylurea of guanosine 6 (UG) in chloroform. The UG unit can be prepared in four steps from guanosine on a 10 g scale in excellent yields without chromatographic purification. The association constant (Kassoc ≈ 5 × 107 M-1) for the UG·DAN complex determined by fluorescence energy transfer from the naphthyridine unit of 3 to coumarin 343 covalently linked UG (18) is among the highest reported for a neutral DNA base-pair analogue. The weak self-association of DAN (Kdimer -1) and UG (Kdimer ca. 200-300 M-1) means that the UG·DAN complex forms with unparalleled fidelity.
- Park, Taiho,Todd, Eric M.,Nakashima, Shoji,Zimmerman, Steven C.
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p. 18133 - 18142
(2007/10/03)
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- INDUCTION OF PHARMACOLOGICAL STRESS WITH ADENOSINE RECEPTOR AGONISTS
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A method is provided employing A2A adenosine receptor agonists as vasodilators to detect the presence and assess the severity of coronary artery stenosis.
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Page/Page column 9
(2010/02/10)
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- Facile, chemoenzymatic synthesis of the potent antiviral compound, 2-acetonylinosine
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A facile and efficient methodology for the chemoenzymatic synthesis of the antiviral compound, 2-acetonylinosine has been developed. The present synthetic strategy, which has generality, is a dramatic improvement on the methodologies currently available for the synthesis of functionalized purine nucleosides of therapeutic interest.
- Gupta, Mukta,Nair, Vasu
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p. 1165 - 1167
(2007/10/03)
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- Inhibitors of inosine monophosphate dehydrogenase: Probes for antiviral drug discovery
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The role of inosine monophosphate dehydrogenase (IMPDH) at the metabolic branch point of de novo purine nucleotide biosynthesis makes this enzyme an attractive probe for the discovery of antiviral compounds. Introduction of unsaturation at the 2-position of IMP, the natural substrate for IMPDH, produces Michael acceptors at that position, which results in these compounds being inhibitors of IMPDH. Consistent with this mechanism-based molecular design, some of the parent nucleosides exhibited antiviral activity. Copyright Taylor & Francis, Inc.
- Story, Sherry,Gupta, Mukta,Bonsu, Eric,Nair, Vasu
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p. 717 - 720
(2007/10/03)
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- ADENOSINE A3 RECEPTOR AGONISTS
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Disclosed are novel adenosine A3 receptor agonists, useful for treating various disease states, including neurological and cardiac ischemia, asthma, leukopenia and neutropenia, cancer and inflammation.
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- Synthesis of 2-aralkoxyadenosines and 2-alkoxyadenosines
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The invention provides new methods for synthesis of 2-aralkyloxyadenosines and 2-alkoxyadenosines. The invention is particularly useful for synthesis of 2-[2-(4-chlorophenyl)ethoxy]adenosine. Preferred methods of the invention include activating a guanosine compound followed by hydrolysis; alkylating the hydrolyzed compound with subsequent animation to provide a 2-aralkyloxyadenosine or a 2-alkoxyadenosine compound.
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Page/Page column 4
(2008/06/13)
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- Efficient methods for the synthesis of [2-15N]guanosine and 2′-deoxy[2-15N]guanosine derivatives
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The nucleophilic addition-elimination reaction of 2′,3′, 5′-tri-O-acetyl-2-fluoro-O6-[2-(4-nitrophenyl)ethyl]inosine (8) with [15N]benzylamine in the presence of triethylamine afforded the N2-benzyl[2-15N]guanosine derivative (13) in a high yield, which was further convened into the N2-benzoyl[2-15N] guanosine derivative by treatment with ruthenium trichloride and tetrabutylammonium periodate. A similar sequence of reactions of 2′, 3′, 5′-tri-O-acetyl-2-fluoro-O6-[2-(methylthio)ethyl]inosine (9) and the 6-chloro-2-fluoro-9-(β-D-ribofuranosyl)-9H-purine derivative (11), which were respectively prepared from guanosine, with potassium [15N]phthalimide afforded the N2-phthaloyl [2-15N]guanosine derivative (15; 62%) and 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-6-chloro-2- [15N]phthalimido-9H-purine (17; 64%), respectively. Compounds 15 and 17 were then efficiently converted into 2′,3′,5′-tri-O-acetyl [2-15N]guanosine. The corresponding 2′-deoxy derivatives (16 and 18) were also synthesized through similar procedures.
- Kamaike,Kinoshita,Niwa,Hirose,Suzuki,Ishido
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- Reaction of arylnitrenium ions with guanine derivatives: N1-methylguanosine and N2,N2-dimethylguanosine
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A prior flash photolysis study of the direct reaction of arylnitrenium ions with 2′-deoxyguanosine identified a second intermediate that grew in as the transient nitrenium ion reacted with the nucleoside. This intermediate was identified as the the product of the addition of the nitrenium ion to the C-8 position of guanine prior to loss of the C-8 proton - the C-8 intermediate. A feature of the C-8 intermediate is that it exists in acid-base forms. This behavior was evident in both a spectroscopic analysis as well as in the rate-pH profile, which showed a break around pH 4 from a pH-independent reaction to a reaction that was first-order in H+. The present study was designed to identify the structure of the conjugate base form. This involved a kinetic study of the decay of the C-8 intermediate derived from the reaction of the 2-fluorenylnitrenium ion with N1-methylguanosine and N2,N2-dimethylguanosine. The rationale was that the former is unable to lose the N-1 proton, while the latter cannot deprotonate at the NH2 group. The rate-pH profiles clearly show that it is the N-1 proton that is acidic. The rate constants for the C-8 intermediate of N2,N2-dimethylguanosine show the same downward break observed with 2′-deoxyguanosine and guanosine associated with conversion to the conjugate base form. In contrast, the rate constants for the N1-methylguanosine intermediate are independent of pH. Rate constants for the reaction forming the C-8 intermediate are also reported. These show that the reaction of nitrenium ions with the N2,N2-dimethylguanine derivative is significantly faster (except where the reactions are diffusion controlled). This is consistent with the initial step of the reaction of an arylnitrenium ion and guanine occurring by direct addition at C-8. The developing positive charge in such a reaction can be delocalized to the C-2 position where π donors such as NH2 and NMe2 can exert a stabilizing effect.
- Cheng, Bernice,McClelland, Robert A.
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p. 1881 - 1886
(2007/10/03)
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- The discovery and synthesis of highly potent, A(2a) receptor agonists
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A series of N6,2-disubstituted adenosine analogues have been synthesized and their functional activity measured against A(2a) and A1 receptors. Examples of compounds with both a lipophilic N6-substituent and amino-functionalized 2-position were highly active at the A(2a) receptor on the human neutrophil. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.
- Keeling, Suzanne E.,Albinson, F. David,Ayres, Barry E.,Butchers, Peter R.,Chambers, C. Lynn,Cherry, Peter C.,Ellis, Frank,Ewan, George B.,Gregson, Michael,Knight, John,Mills, Keith,Ravenscroft, Paul,Reynolds, Linda H.,Sanjar, Shahin,Sheehan, Michael J.
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p. 403 - 406
(2007/10/03)
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