- Tritylation of alcohols under mild conditions without using silver salts
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Secondary alcohols were conveniently tritylated under mild conditions within a short running time with tritylium trifluoroacetate generated in situ from trityl alcohols and trifluoroacetic anhydride. No expensive silver salts were needed for the reactions. Four secondary alcohols were tritylated with both mono- and dimethoxy trityl alcohols giving good to excellent isolated yields. The reaction was also tested on four nucleoside derivatives that have primary alcohols. Satisfactory results were also obtained.
- Shahsavari, Shahien,Chen, Jinsen,Wigstrom, Travis,Gooding, James,Gauronskas, Alexander,Fang, Shiyue
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supporting information
p. 3877 - 3880
(2016/08/02)
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- A new and convenient approach for the preparation of β-cyanoethyl protected trinucleotide phosphoramidites
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Herein we report a convenient approach for the preparation of fully protected trinucleotide synthons to be used for the synthesis of gene libraries. The trinucleotide synthons bear β-cyanoethyl groups at the phosphate residues, and thus can be used in standard oligonucleotide synthesis without additional steps for deprotection and work-up.
- Janczyk, Matthaeus,Appel, Bettina,Springstubbe, Danilo,Fritz, Hans-Joachim,Mueller, Sabine
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p. 1510 - 1513
(2012/03/22)
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- COMPOUNDS FOR TREATING BACTERIAL INFECTIONS
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The present invention relates to a novel class of guanine nucleotide analogs which inhibit RelA and Relseq synthetic activity and which possess anti-bacterial activity. The present invention also relates to pharmaceutical compositions that include such compounds, and to methods of use of such compounds or compositions for combating bacteria and treating bacterial infections.
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- Improved and Reliable Synthesis of 3′-Azido-2′,3′ -dideoxyguanosine Derivatives
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An improved synthesis of N2-protected-3′-azido-2′ ,3′-dideoxyguinosine 20 and 23 is described. Deoxygenation of 2′-O-alkyl (and/or aryl) sulfonyl-5′-dimethoxytritylguanosine coupled with [1,2]-hydride shift rearrangement gave protected 9-(2-deoxythreo-pentofuranosyl)guanines (10, 12 and 16). This rearrangement was accomplished in high yield with a high degree of stereoselectivity using lithium triisobutylborohydride (L-Selectride R). Compounds 10, 12 and 16 were transformed into 3′-O-mesylates (18 and 21), which can be used for 3′-substitution. The 3′-azido nucleosides were obtained by treatment of 18 and 21 with lithium azide. This procedure is reproducible with a good overall yield.
- Timoshchuk, Victor A.,Hogrefe, Richard I.,Vaghefi, Morteza M.
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p. 171 - 181
(2007/10/03)
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- Method for purifying 5' -protected 2' -deoxypurine nucleosides
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A method for efficiently purifying 5′ protected 2′-deoxypurine nucleosides, efficient production of which has previously been difficult. Impurities can be separated by obtaining the 5′ protected 2′-deoxypurine nucleoside as an inclusion crystal including a solvent such as that having a nitrile structure in order to purify the 5′ protected 2′-deoxypurine nucleoside at a high purity. This invention enables synthesis of highly purified protected deoxypurine nucleosides easily on a large scale, which has previously been performed by column chromatography method.
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- Method for purifying 5'-protected 2'-deoxypurine nucleosides
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A method for efficiently purifying 5' protected 2'-deoxypurine nucleosides, efficient production of which has previously been difficult. Impurities can be separated by obtaining the 5' protected 2'-deoxypurine nucleoside as an inclusion crystal including a solvent such as that having a nitrile structure in order to purify the 5' protected 2'-deoxypurine nucleoside at a high purity. This invention enables synthesis of highly purified protected deoxypurine nucleosides easily on a large scale, which has previously been performed by column chromatography method.
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- A mild and efficient method for the preparation of 5'-dimethoxytrityl- 2'-deoxynucleoside using poly(4-vinylpyridine)costyrene
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5'-O-4,4'-Dimethoxytrityl-2'-deoxynucleosides have been synthesized in high yield by the reaction of 2'-deoxynucleosides with 4, 4'-dimethoxytrityl chloride in acetonitrile using poly (4-vinylpyridine)-costyrene(styrene 10%).
- Karalkar, Nilesh B.,Akerkar, Vinayak G.,Salunkhe, Manikrao M.
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p. 370 - 371
(2007/10/03)
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- Nucleoside 5'-methylene phosphonates
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Novel oligonucleotides analogs and nucleoside analogs as well as methods for their synthesis are described. The oligonucleotides are useful in diagnostic and therapeutic applications. The oligonucleotides are stable to nuclease degradation.
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- 2-Vinylpyridine : A novel reagent for O6 protection of 2′-deoxyguanosine
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2-Vinylpyridine has been successfully used for the protection of O6/N-1-lactam function in N2, 3′, 5′-protected 2′-deoxyguanosine followed by phosphonylation at 3′-end to yield the fully protected monomer for oligonucleotide synthesis, It is easier to introduce this group and then deprotect under milder conditions using 1, 8-diazabicyclo[5.4.0]undec-7-ene in anhyd. pyridine. Two oligonucleotides, viz. a hexamer, d(ACTGGC) and an octamer, d(GCCACTGT) have been synthesised in fairly good yields using this monomer on solid-phase without any side reactions.
- Kumar, Prabhat,Singh,Misra
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p. 657 - 661
(2007/10/03)
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- Facile methods to recycle nucleosides during solid phase synthesis of oligonucleotides
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Solid phase syntheses of oligonucleotides, using nucleoside phosphoramidites or methylphosphonamidites require a large excess of nucleoside monomers over the hydroxy functions of the growig oligonucleotide chain bound onto the solid phase. The outlined method allows to recover the excess nucleosides. All the protective groups on the sugar and the nucleobase of the monomers are maintained throughout the recycling process.
- Brill, Wolfgang K.-D.
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p. 3041 - 3044
(2007/10/02)
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- (2-Pyridyl)methyl, a novel rwagent for O6 protection of 2'-deoxyguanosine
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(2-Pyridyl)methyl group has been successfully used for the protection of O6 function in partially protected 2'-deoxyguanosine via 'Mitsunobu alkylation' to yield the fully protected monomer units for oligonucleotide synthesis.The group is easier to introduce and deprotect under milder conditions using 1,8-diazabicycloundec-7-ene (DBU) in anhyd. pyridine.A trimer d(GGA) and hexamer d(GGATCC) have been synthesized using this protected unit without any significant side reactions.
- Awasthi, S. K.,Khanna, V.,Watal, G.,Misra, K.
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p. 916 - 919
(2007/10/02)
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- Simplified Liquid-Phase Preparation of Four Decadeoxyribonucleotides and their Preliminary Spectroscopic Characterization
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Four self-complementary decadeoxyribonucleotides, dApTpApTpApTpApTpApT,dApTpApTpCpGpApTpApT, dApTpApTpGpCpApTpApT and dApApApApApTpTpTpTpT, were chemically synthesized by the phosphotriester procedure.Efforts were concentrated on keeping the procedure as simple as possible, concomitant with obtaining high-purity products at each step of the process.The decamers were elaborated from the 3'-end, starting with a 3'-O-benzoylated monomer according to the scheme: monomer + monomer -> dimer + dimer -> tetramer + dimer -> hexamer + tetramer -> decamer.Putity of intermediates and of the fully blocked decamers were monitored by chromatography and by 300-MHz 1H-NMR. spectroscopy.The deblocked decadeoxyribonucleotides were characterized by their UV., CD., and 1H-NMR. spectra.
- Denny, William A.,Leupin, Werner,Kearns, David R.
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p. 2372 - 2393
(2007/10/02)
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