- Synthesis of 2,6-dihalogenated purine nucleosides by thermostable nucleoside phosphorylases
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The enzymatic transglycosylation of 2,6-dichloropurine (26DCP) and 6-chloro-2-fluoropurine (6C2FP) with uridine, thymidine and 1-(β-D-arabinofuranosyl)-uracil as the pentofuranose donors and recombinant thermostable nucleoside phosphorylases from G. thermoglucosidasius or T. thermophilus as biocatalysts was studied. Selection of 26DCP and 6C2FP as substrates is determined by their higher solubility in aqueous buffer solutions compared to most natural and modified purines and, furthermore, synthesized nucleosides are valuable precursors for the preparation of a large number of biologically important nucleosides. The substrate activity of 26DCP and 6C2FP in the synthesis of their ribo- and 2′-deoxyribo-nucleosides was closely similar to that of related 2-amino- (DAP), 2-chloro- and 2-fluoroadenines; the efficiency of the synthesis of β-D-arabinofuranosides of 26DCP and 6C2FP was lower vs. that of DAP under similar reaction conditions. For a convenient and easier recovery of the biocatalysts, the thermostable enzymes were immobilized on MagReSyn epoxide beads and the biocatalyst showed high catalytic efficiency in a number of reactions. As an example, 6-chloro-2-fluoro-(β-D-ribofuranosyl)-purine (9), a precursor of various antiviral and antitumour drugs, was synthesized by the immobilized enzymes at 60°C under high substrate concentrations (uridine:purine ratio of 2:1, mol). The synthesis was successfully scaled-up [uridine (2.5 mmol), base (1.25 mmol); reaction mixture 50 mL] to afford 9 in 60% yield. The reaction reveals the great practical potential of this enzymatic method for the efficient production of modified purine nucleosides of pharmaceutical interest.
- Zhou, Xinrui,Szeker, Kathleen,Jiao, Lin-Yu,Oestreich, Martin,Mikhailopulo, Igor A.,Neubauer, Peter
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- Design, synthesis and biological evaluation of 2-hydrazinyladenosine derivatives as A2A adenosine receptor ligands
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To obtain potential A2A adenosine receptor agonists, a series of 2-hydrazinyladenosine derivatives were synthesized and assayed for adenosine receptors activity using radioligand binding activity assays. The binding activity of the subtypes was examined, and the structure-activity relationship of this class of compounds at the A2A receptor was investigated. A fragment-based computer-aided design method was used to modify the 2-position side chain structures with different structural fragments, and the newly generated molecules were docked to the A2A receptor to assess scoring and screening activity. To synthesize compounds with better scoring activity, the newly synthesized compounds were tested for in vitro receptor binding activity. 2-Hydrazinyladenosine derivatives of 32 new structural types were designed and synthesized, with the most potent adenosine derivative 23 exhibiting a Ki value of 1.8 nM for A2AAR and significant selectivity for the A2A receptor compared to the A1 receptor. In addition to, compound 23, 24, 30, 31, and 42 also exhibited potent A2A receptor selectivity, with Ki values for the A2A receptor of 6.4, 20, 67 and 6.3 nM, respectively. We also found that compound 35 has a high A1 receptor selectivity, with a Ki value for the A1 receptor of 4.5 nM. Further functional assays also demonstrated that these compounds have potent A2A receptor agonist activity. The study shows the applicability of an in silico fragment-based molecular design for rational lead optimization in A2AAR.
- Zhang, Min,Fan, Shiyong,Zhou, Xinbo,Xie, Fei,Li, Song,Zhong, Wu
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- Intermediate for synthesizing 2-chloroadenosine, synthesis process of intermediate and synthesis process of 2-chloroadenosine
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The invention relates to the technical field of organic synthesis, in particular to an intermediate for synthesizing 2-chloroadenosine, a synthesis process of the intermediate and a synthesis processof the 2-chloroadenosine. The synthesis process of the intermediate for synthesizing the 2-chloroadenosine comprises the following step: carrying out condensation reaction on 2,6-dichloropurine and tetraacetylribose under the catalytic action of 4-dimethylaminopyridine to form 2,3,5-4-triacetyl-2,6-dichloropurine riboside. The synthesis process is simple to operate, low in catalyst dosage, low incost, low in pollution and easy to industrially implement, and the yield and purity of the synthesized 2-chloroadenosine are higher.
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- Efficient biocatalytic synthesis of dihalogenated purine nucleoside analogues applying thermodynamic calculations
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The enzymatic synthesis of nucleoside analogues has been shown to be a sustainable and efficient alternative to chemical synthesis routes. In this study, dihalogenated nucleoside analogues were produced by thermostable nucleoside phosphorylases in transglycosylation reactions using uridine or thymidine as sugar donors. Prior to the enzymatic process, ideal maximum product yields were calculated after the determination of equilibrium constants through monitoring the equilibrium conversion in analytical-scale reactions. Equilibrium constants for dihalogenated nucleosides were comparable to known purine nucleosides, ranging between 0.071 and 0.081. To achieve 90% product yield in the enzymatic process, an approximately five-fold excess of sugar donor was needed. Nucleoside analogues were purified by semi-preparative HPLC, and yields of purified product were approximately 50% for all target compounds. To evaluate the impact of halogen atoms in positions 2 and 6 on the antiproliferative activity in leukemic cell lines, the cytotoxic potential of dihalogenated nucleoside analogues was studied in the leukemic cell line HL-60. Interestingly, the inhibition of HL-60 cells with dihalogenated nucleoside analogues was substantially lower than with monohalogenated cladribine, which is known to show high antiproliferative activity. Taken together, we demonstrate that thermodynamic calculations and small-scale experiments can be used to produce nucleoside analogues with high yields and purity on larger scales. The procedure can be used for the generation of new libraries of nucleoside analogues for screening experiments or to replace the chemical synthesis routes of marketed nucleoside drugs by enzymatic processes.
- Giessmann, Robert T.,Kaspar, Felix,Klare, Hendrik F. T.,Kurreck, Jens,Neubauer, Peter,Paulick, Katharina,R?hrs, Viola,Wagner, Anke,Westarp, Sarah,Yehia, Heba
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- A acyl-removing and protect the 2, 6 - position halogenated purine nucleoside method (by machine translation)
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Invention discloses a deacylated and protect the 2, 6 - position halogenated purine nucleoside. In order to acetyl or benzoyl protection of 2, 6 - position halogenated purine nucleoside as raw materials, using acetyl chloride/alcohol system carries acetyl or benzoyl to obtain 2, 6 - position halogenated purine nucleoside, the method avoids the conventional method liquid ammonia/methanol or hydrochloric acid/methanol system, halogen atoms are amino or alkoxy substituted by-product, after treatment is simple, and high product purity, is suitable for industrial scale production. (by machine translation)
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Paragraph 0019; 0020; 0021; 0022
(2018/01/13)
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- Method for compounding 2,6-dichloropurine nucleoside by using inosine as raw material
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The invention discloses a method for compounding 2,6-dichloropurine nucleoside by using inosine as a raw material. The method is characterized by using cheap inosine as the raw material; obtaining 6-chlorine triacetyl purine nucleoside through acetylation
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Paragraph 0021; 0027; 0028
(2016/11/07)
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- Direct One-Pot Synthesis of Nucleosides from Unprotected or 5-O-Monoprotected d -Ribose
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New, improved methods to access nucleosides are of general interest not only to organic chemists but to the greater scientific community as a whole due their key implications in life and disease. Current synthetic methods involve multistep procedures employing protected sugars in the glycosylation of nucleobases. Using modified Mitsunobu conditions, we report on the first direct glycosylation of purine and pyrimidine nucleobases with unprotected d-ribose to provide β-pyranosyl nucleosides and a one-pot strategy to yield β-furanosides from the heterocycle and 5-O-monoprotected d-ribose.
- Downey, A. Michael,Richter, Celin,Pohl, Radek,Mahrwald, Rainer,Hocek, Michal
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supporting information
p. 4604 - 4607
(2015/09/28)
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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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