- Chemoselective N-Deacetylation of Protected Nucleosides and Nucleotides Promoted by Schwartz's Reagent
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Protection and deprotection strategies involving the N-acetyl group are widely utilized in nucleoside and nucleotide chemistry. Herein, we present a mild and selective N-deacetylation methodology, applicable to purine and pyrimidine nucleosides, by means of Schwartz's reagent, compatible with most of the common protecting groups used in nucleoside chemistry.
- Ferrari, Valentina,Serpi, Michaela,McGuigan, Christopher,Pertusati, Fabrizio
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p. 799 - 814
(2015/11/17)
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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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- '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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- Hydrothermal deamidation of 4-N-acylcytosine nucleoside derivatives: Efficient synthesis of uracil nucleoside esters
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(Chemical Equation Presented) N,O-Peracylated cytidine and 2′-deoxycytidine derivatives in superheated water/DME solutions (oil bath at 125°C) undergo hydrolytic deamidation (and/or N-deacylation). Acylated starting materials derived from arylcarboxylic acids give the corresponding uridine esters cleanly, and such derivatives crystallize selectively from the cooled reaction mixtures in high yields.
- Nowak, Ireneusz,Robins, Morris J.
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p. 4903 - 4905
(2007/10/03)
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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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- 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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- 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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- 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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- REACTION OF URACIL NUCLEOSIDES WITH 1-METHYLIMIDAZOLE IN THE PRESENCE OF PHOSPHORYL CHLORIDE: A CONVENIENT METHOD FOR THE SYNTHESIS OF 4-SUBSTITUED PYRIMIDIN-2(1H)-ONE NUCLEOSIDES
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Reaction of 2',3',5'-tri-O-benzoyluridine (3) with 1-methylimidazole in the presence of phosphoryl chloride in acetonitrile afforded 3-methyl-1-imidazolium intermediate (4), from which a variety of 4-substituted pyrimidin-2(1H)-one ribosides (5-12) were o
- Matsuda, Akira,Obi, Kikoh,Miyasaka, Tadashi
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p. 2574 - 2578
(2007/10/02)
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- Nucleoside Syntheses, XXV. A New Simplified Nucleoside Synthesis
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The several steps of the Friedel-Crafts catalyzed silyl-Hilbert-Johnson nucleoside synthesis - silylation of the heterocyclic base, silylation of the perfluorosulfonic acids or its salts (if SnCl4 is not used as catalyst) and finally the nucleoside synthesis itself - can be combined to a simple one-step/one-pot reaction which generally affords nucleosides in high yields.
- Vorbrueggen, Helmut,Bennua, Baerbel
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p. 1279 - 1286
(2007/10/02)
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- Nucleoside Syntheses, XXII. Nucleoside Synthesis with Trimethylsilyl Triflate and Perchlorate as Catalysts
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The novel Lewis acids (CH3)3SiOSO2CF3 (5), (CH3)3SiOSO2C4F9 (6), and (CH3)3SiClO4 (4) are highly selective and efficient Friedel-Crafts catalysts for nucleoside formation from silylated heterocycles and peracylated sugars as well as for rearrangements of persilylated protected nucleosides.With basic silylated heterocycles these new catalysts give much higher yields of the natural N-1-nucleosides than with SnCl4.
- Vorbrueggen, Helmut,Krolikiewicz, Konrad,Bennua, Baerbel
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p. 1234 - 1255
(2007/10/02)
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- Partial Protection of Carbohydrate Derivatives. Part 4. Regioselective 2'-O-Deacylation of Fully Acylated Purine and Pyrimidine Ribonucleosides with Hydroxylaminium Acetate
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Like hydrazine hydrate, hydroxylamine was found to be useful for the regioselective 2'-O-deacylation of fully acylated purine and pyrimidine ribonucleosides as its salt with acetic acid; the partial O-deacylation reactions (which were not accompanied by undesirable discolouration as happens with hydrazine hydrate) gave the corresponding di-O-acylribonucleosides in superior yields; e.g. 2',3'-di-O-benzoyladenosine (74percent yield), 3',5'- (64percent yield) and 2',5'-di-O-benzoyl-N6-benzyladenosine (63percent yield on performing the reaction in ethanol), N2,3',5'-tri-O-benzoylguanosine (66percent yield), N2,2',5'-tri-isobutyrylguanosine (48percent yield), and 3',5'-di-O-benzoyluridine (61percent yield) were obtained using hydroxylaminium acetate in pyridine.Treatment of fully acetylated ribonucleosides with an excess of hydroxylaminium acetate gave the corresponding 5'-O-acetylribonucleosides in quantitative yields.The excellent regioselectivity observed in the present partial O-decyclation was confirmed on the basis of chromatographic separation; the mixtures of di-O-acylribonucleosides, which had already been equilibrated in pyridine, were re-equilibrated on the silica gel during separation, e.g. a 70 : 30 mixture of 3',5'- and 2',5'-di-O-benzoyladenosine was completely converted into the former based on 1H n.m.r spectroscopy.The acetates of 9-β-D-xylo- and -arabino-furanosyladenine were also found to give predominantly the corresponding 3',5'-diacetates on hydroxylaminolysis.
- Ishido, Yoshiharu,Sakairi, Nobuo,Okazaki, Kei,Nakazaki, Nobuo
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p. 563 - 573
(2007/10/02)
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