- Selective Acylation of Nucleosides, Nucleotides, and Glycerol-3-phosphocholine in Water
-
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.
-
supporting information
p. 78 - 83
(2016/12/26)
-
- Efficient and green approach for the complete deprotection of O-acetylated biomolecules
-
A simple, efficient and mild strategy for the complete O-deacetylation of different per-acetylated biomolecules in aqueous media has been described. Different lipases were tested but only the commercial Amano lipase A from Aspergillus Niger catalyzed the complete deprotection of peracetylated α-glucose to glucose in excellent yield. The experimental conditions were tested, in particular the pH effect. The reaction was performed at different pHs considering the only enzymatic process was evaluated at pH 5 and the combination of enzymatic and chemical migration process was evaluated at higher pHs. Finally pH 7 and 25 °C were selected as best conditions. Thus this lipase fully hydrolyzed different peracetylated α-glycopyranosides (glucose, mannose, glucal, galactal) with >99% yields, whereas very good deprotecting yields (75-80%) were achieved for different acetylated β-glycopyranosides (galactose, ribofuranose) under these mild conditions. This strategy was successfully extended to the fully O-selective deprotection of acetylated nucleosides where >99% yield was rapidly obtained. No selectivity was observed for the N-deacetylation in amino acids and peptides.
- Dunne, Anthony,Palomo, Jose M.
-
p. 88974 - 88978
(2016/10/03)
-
- Efficient synthesis of nebularine and vidarabine via dehydrazination of (hetero)aromatics catalyzed by CuSO4 in water
-
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
-
p. 1077 - 1081
(2014/03/21)
-
- Stability studies on the newly discovered cyclic form of tRNA N 6-threonylcarbamoyladenosine (ct6A)
-
A cyclic form of N6-threonylcarbamoyladenosine bearing an oxazolone moiety (ct6A) was discovered very recently at the position 37 in several tRNA sequences. Our study on the synthesized 5′,3′, 2′-O-acetylated derivative of ct6A confirmed high stability of the modified nucleoside under physiological conditions (PBS buffer, pH 7.4) and revealed remarkable stability of the oxazolone ring in acidic (100 mM HCl, pH 1) and basic (0.1 mM NaOH, pH 10) conditions. This feature may allow for the post-synthetic conversion of t6A into ct6A in assembled oligoribonucleotides.
- Matuszewski, Michal,Sochacka, Elzbieta
-
supporting information
p. 2703 - 2706
(2014/06/09)
-
- Synthesis of purine and 7-deazapurine nucleoside analogues of 6-N-(4-nitrobenzyl)adenosine; Inhibition of nucleoside transport and proliferation of cancer cells
-
Human equilibrative nucleoside transporter 1 (hENT1) is a prototypical nucleoside transporter protein ubiquitously expressed on the cell surface of almost all human tissue. Given the role of hENT1 in the transport of nucleoside drugs, an important class of therapeutics in the treatment of various cancers and viral infections, efforts have been made to better understand the mechanisms by which hENT1 modulates nucleoside transport. To that end, we report here the design and synthesis of novel tool compounds for the further study of hENT1. The 7-deazapurine nucleoside antibiotic tubercidin was converted into its 4-N-benzyl and 4-N-(4-nitrobenzyl) derivatives by alkylation at N3 followed by a Dimroth rearrangement to the 4-N-isomer or by fluoro-diazotization followed by SNAr displacement of the 4-fluoro group by a benzylamine. The 4-N-(4-nitrobenzyl) derivatives of sangivamycin and toyocamycin antibiotics were prepared by the alkylation approach. Cross-membrane transport of labeled uridine by hENT1 was inhibited to a weaker extent by the 4-nitrobenzylated tubercidin and sangivamycin analogues than was observed with 6-N-(4-nitrobenzyl)adenosine. Type-specific inhibition of cancer cell proliferation was observed at micromolar concentrations with the 4-N-(4-nitrobenzyl) derivatives of sangivamycin and toyocamycin, and also with 4-N-benzyltubercidin. Treatment of 2′,3′,5′-O-acetyladenosine with aryl isocyanates gave the 6-ureido derivatives but none of them exhibited inhibitory activity against cancer cell proliferation or hENT1.
- Rayala, Ramanjaneyulu,Theard, Patricia,Ortiz, Heysell,Yao, Sylvia,Young, James D.,Balzarini, Jan,Robins, Morris J.,Wnuk, Stanislaw F.
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p. 2186 - 2192
(2014/11/07)
-
- A versatile synthesis of 5'-fenctionalized nucleosides through regioselective enzymatic hydrolysis of their peracetylated precursors
-
We describe a chemo-enzymatic synthesis of modified nucleosides through lipase-catalyzed hydrolysis of their peracetylated precursors. It was found from screening of a large number of substrates that these enzymesregioselectivities were affected by the sugar and the nucleobase structures. By selecting the best enzyme for each substrate in terms of activity and regioselectivity, we prepared a small library of differently monodeprotecled purine and pyrimidine nucleosides useful as intermediates for the synthesis of high-value nucleosides and mononucleotides. By this approach, the chemo-enzymatic preparation of doxifluridine (14) and uridine 5'-monophosphate (5'-UMP, 15) from peracetylated uridine 1 was carried out. Elimination of many of the processing stages associated with existing methods was achieved, and higher yields and products of increased purity were generated. Wiley-VCH Verlag GmbH & Co. KGaA.
- Bavaro, Teodora,Rocchietti, Silvia,Ubiali,Filice, Marco,Terreni, Marco,Pregnolato, Massimo
-
experimental part
p. 1967 - 1975
(2009/09/08)
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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
-
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.
- -
-
Page/Page column 25-26
(2008/12/05)
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- Synthesis of guanosine 5′-conjugates and their use as initiator molecules for transcription priming
-
We have synthesised two guanosine derivatives that are linked to biotinylated adenosine moieties by using two different strategies, one that includes synthetic steps on the solid phase and another one that is performed entirely in solution. The synthesised derivatives were shown to function as initiator molecules in transcription priming experiments. The incorporation efficiency was determined to be approximately 2%. Even though this value is rather low, the use of either molecule in selection experiments seems reasonable. Basically, RNA libraries with sequence complexities of 10 15 to 1016 can be generated. Labelling of such a library with our initiator molecule would still produce 1013 to 10 14 labelled/functionalised sequences, and thus sufficient sequence space for selection. The Royal Society of Chemistry.
- Wolf, Joern,Dombos, Valeska,Appel, Bettina,Mueller, Sabine
-
supporting information; experimental part
p. 899 - 907
(2008/10/09)
-
- Spectral assignments and reference data complete1H and 13C NMR spectral assignment of α- And β-adenosine, 2′-deoxyadenosine and their acetate derivatives
-
1H and 13C NMR chemical shifts of α- and β-anomers of adenosine, 2′-deoxyadenosine and their acetate derivatives were completely and definitely assigned using the concerted application of one- and two-dimensional experiments (gCOSY, gNOESY, gHSQC and gHMBC). The influence of the stereochemistry of the purine base on the NMR data of the hydrogen and carbon atoms of the furanose moiety was estimated. Copyright
- Ciuffreda,Casati,Manzocohi
-
p. 781 - 784
(2008/03/17)
-
- A reinvestigated mechanism of ribosylation of adenine under silylating conditions
-
The mechanism of chemical synthesis of adenosine has been reinvestigated. Depending on the reaction conditions and the presence of N6-protecting groups, ribosylation of adenine proceeds via different kinetic products: 3-riboadenine in strongly acidic media, 7-ribosylated derivative in the silyl method, and 1-(β-d-ribofuranosyl)adenine when applying N6-acyladenine and silylating conditions.
- Framski, Grzegorz,Gdaniec, Zofia,Gdaniec, Maria,Boryski, Jerzy
-
p. 10123 - 10129
(2007/10/03)
-
- Synthesis and enzymic hydrolysis of acylated adenosine derivatives
-
Various derivatives of adenosine were prepared by acylation of adenosine (6-amino-9-(β-D-ribofuranosyl)purine (1) with different molar equivalents of acetic anhydride and/or pivaloyl chloride in pyridine. Compounds 6-acetylamino-9-[(2,3,5-tri-O-acetyl)-β-D-ribofuranosyl]purine (3), 6-amino-9-[(2,3,5-tri-O-acetyl)-β-D-ribofuranosyl]purine (4), and 6-pivaloylamino-9-[(2,3,5-tri-O-pivaloyl)-β-D-ribofuranosyl]purine (5) were subsequently submitted to hydrolysis catalyzed by a number of hydrolytic enzymes. Regioselective enzymic deacetylation at the primary hydroxyl group of 3 and 4 with butyrylcholinesterase (BChE) produced 6-acetylamino-9-[(2,3-di-O- acetyl)-β-D-ribofuranosyl]purine (9) and 6-amino-9-[(2,3-di-O-acetyl- β-D-ribofuranosyl]purine (10), respectively. All structures were established by 1H and 13C NMR spectroscopies.
- Car,Petrovic,Tomic
-
p. 713 - 723
(2007/10/03)
-
- Nucleic acid related compounds. 127. Selective N-deacylation of N,O-peracylated nucleosides in superheated methanol
-
Solutions of peracylated adenosine, cytidine, and related nucleoside derivatives undergo selective N-deacylation upon heating at elevated temperatures (oil bath ≥ 105 °C) in methanol. An increase in the bulk of the N-acyl group has little effect on the rate of N-deacylation but increases the N/O selectivity ratio. Extended heating is required for N-deacylation with arylcarboxylic acid derivatives. Contamination with acidic or basic reagent residues is avoided.
- Nowak, Ireneusz,Conda-Sheridan, Martin,Robins, Morris J.
-
p. 7455 - 7458
(2007/10/03)
-
- Synthesis of new substituted 6-ureidopurines and 6-ureido-9-(2,3,5-triacetyl ribofuranosyl)purines having cytokinin (plant growth promoting) activity
-
Substituted 6-ureidopurines 6a-j and 6-ureido-9-(2,3,5-triacetylribofuranosyl) purines 7a-j have been synthesized by condensing substituted phenyl isocyanates with adenine 3 and 2,3,5-triacetyladenosine 5 respectively in pyridine. Substituted phenyl isocyanates 2a-j are prepared from substituted anilines 1a-j in the presence of triphosgene and triethylamine in dry benzene. Compounds 6a-j and 7a-j have been evaluated for cytokinin activity on seeds of Raphanus sativus, family Brassicaceae (common name white radish) at 5 different concentrations in distilled water ranging from 0.001 to 10 mg litre-1. Compounds 6a, 7a, 7b and 7i having substitutents at 3 position of phenyl ring are found to show higher cytokinin activity than benzyladenine at all concentrations (Table II).
- Mhatre, Vandana,Joshi, Vidya
-
p. 2667 - 2675
(2007/10/03)
-
- Synthesis and characterization of the native anticodon domain of E. coli tRNA(Lys): Simultaneous incorporation of modified nucleosides mnm5s2U, t6A, and pseudouridine using phosphoramidite chemistry
-
The anticodon domain of E. coli tRNA(Lys) contains the hypermodified nucleosides mnm5s2U and t6A at positions 34 and 37, respectively, along with a more common ψ at position 39. The combination of these three nucleotides represents one of the most extensively modified RNA domains in nature. 2-Cyanoethyl diisopropylphosphoramidites of the hypermodified nucleosides mnm5s2U and t6A were each synthesized with protecting groups suitable for automated RNA oligonucleotide synthesis. The 17 nucleotide anticodon stem-loop of E. coli tRNA(Lys) was then assembled from these synthons using phosphoramidite coupling chemistry. Coupling efficiencies for the two hypermodified nucleosides and for pseudouridine phosphoramidite were all greater than 98%. A mild deprotection scheme was developed to accommodate the highly functionalized RNA. High coupling yields, mild deprotection, and efficient HPLC purification allowed us to obtain 1.8 mg of purified RNA from a 1 μmol scale RNA synthesis. Our efficient synthetic protocol will allow for biophysical investigation of this rather unique tRNA species wherein nucleoside modification has been shown to play a role in codon-anticodon recognition, tRNA aminoacyl synthetase recognition, and programmed ribosomal frameshifting. The human analogue, tRNA(Lys,3), is the specific tRNA primer for HIV-1 reverse transcriptase and has a similar modification pattern.
- Sundaram, Mallikarjun,Crain, Pamela F.,Davis, Darrell R.
-
p. 5609 - 5614
(2007/10/03)
-
- Preparation and reactions of new zincated nitrogen-containing heterocycles
-
A range of nitrogen-containing iodinated or in some cases brominated heterocycles were converted to the corresponding zincated heterocyclic derivatives by the direct insertion of zinc dust under mild conditions (25°C to 70°C, 1-3 h) in a solvent like THF or DMAC. This reaction was extended to the preparation of zincated nucleic acid bases and nucleosides. The reaction of these new zinc reagents toward various electrophiles with palladium (O) or copper(I) catalysis allows the preparation of a broad range of polyfunctional nitrogen-containing heterocycles.
- Prasad, A. S. Bhanu,Stevenson, Thomas M.,Citineni, Janakiram Rao,Nyzam, Valerie,Knochel, Paul
-
p. 7237 - 7254
(2007/10/03)
-
- New base-altered adenosine analogues: Synthesis and affinity at adenosine A1 and A(2A) receptors
-
N6-Substituted adenosine analogues containing cyclic hydrazines or chiral hydroxy (ar)alkyl groups, designed to interact with the S2 and S3 receptor subregions, have been synthesized and their binding to the adenosine A1 and A(2A) receptors have been investigated. Examples of both types of compounds were found to exhibit highly selective binding (K(i) in low nM range) to the rat A1 receptor.
- Ha, Seung B.,Melman, Neli,Jacobson, Kenneth A.,Nair, Vasu
-
p. 3085 - 3090
(2007/10/03)
-
- Transformations of thiopyrimidine and thiopurine nucleosides following oxidation with dimethyldioxirane
-
A general and convenient method for the synthesis of several pyrimidine and purine nucleosides by selective oxidation of thionucleosides with dimethyldioxirane is reported. Thioketo moieties in the C-4 position of the pyrimidine ring, and in the C-6, and C-8 positions of the purine ring are the domain of oxidative nucleophilic substitution. Thioketo moieties in the C-2 position of both purine and pyrimidine rings are the domain of desulfurization or formation of disulfides.
- Saladino, Raffaele,Mincione, Enrico,Crestini, Claudia,Mezzetti, Maurizio
-
p. 6759 - 6780
(2007/10/03)
-
- Aminolysis and alkaline hydrolysis of protected 1-hydroxybenzotriazol-1-yl esters of adenosine 5'-phosphorothioate and -phosphorodithioate
-
When 2',3'-bis-O-(methoxyacetyl)-6-N-(9-phenylxanthen-9-yl)adenosine 9, which was prepared from adenosine in six steps and in ca. 70percent overall yield, was treated with putative tri(benzotriazol-1-yl) phosphorothioate 11 and the products then worked up with aq. triethylamine, the triethylammonium salt of the protected benzotriazol-1-yl ester 6a of adenosine 5'-phosphorothioate was obtained in high yield.The corresponding adenosine 5'-phosphorodithioate derivative 6b was prepared, also in high yield, by a modification of the latter procedure involving work-up with hydrogen sulfide and triethylamine.Reaction between the phosphorothioate derivative 6a and methylamine or morpholine gave the phosphorothioamidates 12a and 13a, respectively, in high yields; in the same way, the phosphorodithioate derivative 6b was converted into the phosphorodithioamidates 12b and 13b.Treatment of the phosphorothioate derivative 6a first with aq. alkali and then with aq. acid gave a mixture of adenosine 5'-phosphorothioate 15a and adenosine 3',5'-cyclic phosphorothioate 17a.When the phosphorodithioate derivative 6b was treated in the same way, adenosine 3',5'-cyclic phosphorodithioate 17b was obtained in good yield.
- Reese, Colin B.,Shek, Louise H. K.,Zhao, Zhengyun
-
p. 3077 - 3084
(2007/10/03)
-
- Nucleosides VII: Synthesis of N-Triphenylphosphoranylidene Nucleosides by Mitsunobu Reaction. A Novel Protecting Group for Primary Amines of Nucleosides
-
N-Triphenylphosphoranylidene nucleosides synthesized by Mitsunobu reaction can be utilized for protecting the amino groups bearing on the base moieties of nucleosides.
- Chien, Tun-Cheng,Chen, Chien-Shu,Yeh, Jun-Yen,Wang, Kuang-Chao,Chern, Ji-Wang
-
p. 7881 - 7884
(2007/10/02)
-
- Ozonation of thionucleosides. A new chemical transformation of 4-thiouracil and 6-thioguanine nucleosides to cytosine and adenosine counterparts
-
The ozonation of 4-thiopyrimidine and 6-thiopurine nucleosides in presence of amines afforded selectively and under mild experimental conditions several cytidine and adenosine nucleosides. The same reaction carried out in presence of alcohols afforded O4- or O6-alkylated derivatives of the nucleosides.
- Saladino, Raffaele,Crestini, Claudia,Occhionero, Francesca,Nicoletti, Rosario
-
p. 3607 - 3616
(2007/10/02)
-
- A New and Efficient Synthesis of Cytidine and Adenosine Derivatives by Dimethyldioxirane Oxidation of Thiopyrimidine and Thiopurine Nucleosides
-
Dimethyldioxirane oxidation of thiopyrimidine and thiopurine nucleosides, in the presence of amines in stoichiometric amount, afforded selectively and under mild experimental conditions cytidine and adenosine nucleosides.
- Saladino, Raffaele,Crestini, Claudia,Bernini, Roberta,Frachey, Giuseppe,Mincione, Enrico
-
p. 3053 - 3054
(2007/10/02)
-
- Nucleic acid related compounds. 81. Syntheses of 9-(3-deoxy-β-D-threo- pentofuranosyl)adenine, the core nucleoside of the extraordinarily selective antibiotic agrocin 84, and simplified structural component analogues
-
Alternative syntheses of 9-(3-deoxy-β-D-threo-pentofuranosyl)adenine (4), the core nucleoside of agrocin 84 [and its 2'-deoxy threo isomer 5] were devised: (1) direct conversion of 9-(β-D-arabinofuranosyl)adenine into 9- (2,3-anhydro-β-D-lyxofuranosyl)adenine and regioselective opening of its oxirane ring with sodium borohydride to give 4 and 5 (~7.5:1); (2) treatment of adenosine with sodium hydride and 2,4,6-triisopropylbenzenesulfonyl chloride, and subjection of the resulting 2'(3')-sulfonates to the reductive [1,2]-hydride shift rearrangement with lithium triethylborohydride to give 4 and 5 (~2:1); and (3) subjection of the phenoxythiocarbonyl esters of 9- [2(3),5-bis-O-(tert-butyldimethylsilyl)-β-D-arabinofuranosyl]adenine to Barton deoxygenation, and deprotection to give 4 and 2'-deoxyadenosine (~5:1). Methods (2) and (3) gave lower yields. Syntheses of simplified 6-N- and 5'-O-adenosine phosphoramidate model compounds were explored to examine potential access to such features in the structure proposed for agrocin 84.
- Vinayak,Hansske,Robins
-
p. 1181 - 1189
(2007/10/02)
-
- Synthesis and Biochemical Properties of 8-Amino-6-fluoro-9-β-D-ribofuranosyl-9H-purine
-
The synthesis and characterization of 8-amino-6-fluoro-9-β-D-ribofuranosyl-9H-purine (3a) are presented.This compound is a substrate for adenosine deaminase and adenosine kinase.In L1210 cells 3a is converted to 8-aminoinosine monophosphate (4b), apparently by the action of AMP deaminase on the monophosphate of 3a, as well as to the triphosphate derivative of 3a.Pentostatin was used to inhibit adenosine deaminase, and coformycin was used to inhibit AMP deaminase in experiments designed to delineate the metabolic fate of 3a.Pentostatin was without influence on the cytotoxicity of 3a, but coformycin potentiated the cytotoxicity.The potentiation was associated with an increased cellular concentration of phosphates of 3a and a decreased concentration of 4b.
- Secrist, John A.,Bennett, L. Lee,Allan, Paula W.,Rose, Lucy M.,Chang, Chi-Hsiung,Montgomery, John A.
-
p. 2069 - 2074
(2007/10/02)
-
- Photoinduced Alkylthiolation of Halogenated Purine Nucleosides
-
A new highly efficient methodology for the synthesis of biologically important methylmercaptopurine nucleosides is described.The approach represents a substantial improvement over earlier reported methods for this class of compounds.
- Nair, Vasu,Young, David A.
-
p. 450 - 453
(2007/10/02)
-
- THE p-NITROPHENYLETHYL (NPE) GROUP. A VERSATILE NEW BLOCKING GROUP FOR PHOSPHATE AND AGLYCONE PROTECTION IN NUCLEOSIDES AND NUCLEOTIDES
-
The syntheses of new monomeric building blocks for oligonucleotide synthesis via the phosphotriester approach containing the p-nitrophenylethyl group for phosphate and aglycone protection are described.Blocking of the amide function in guanosines at O6 can be achieved by the Mitsunobu reaction forming the corresponding O6-p-nitrophenylethyl derivatives (4,5,10).Sugar-protected thymidine (16) and uridine (17) have been alkylated at O4 in an SN1-type reaction by p-nitrophenylethyl iodide-silver carbonate in benzene to form the O4-p-nitrophenylethyl derivatives (18,19).Protection of the amino group in 2'-deoxycytidine (25) and cytidine (26) can be performed directly by 1-(p-nitrophenylethoxycarbonyl)-benzotriazole in DMF to obtain the corresponding carbamates (27,28) as a new type of N4-acylated cytidine derivative. p-Nitrophenylethoxycarbonylation of the amino group in 2'-deoxyadenosine (33) and adenosine (34) requires previous sugar protection by acyl or silyl groups and can then be achieved by p-nitrophenylethyl chloroformate or better by 1-methyl-3-p-nitrophenylethoxycarbonylimidazolium chloride to form N6-p-nitrophenylethoxycarbonyladenosines (38,39,40,42).The various p-nitrophenylethyl blocking groups are stable under mild hydrolytic conditions (e.g. ammonia and triethylamine) but can be cleaved selectively by DBU or DBN in aprotic solvents. 5'-O-Monomethoxytritylation (12,29,43) as well as phosphorylations at the 3'-OH group can be effected to give the corresponding 3'-(2,5-dichlorophenyl,p-nitrophenylethyl)-phosphotriesters (13,22,30,44) also in high yields.Oximate cleavage of the latter compounds to the phosphodiesters (14,24,32,46) and detritylation to the 5'-unblocked phosphotriesters (15,23,31,45) do not affect the aglycone protecting groups, thereby demonstrating their general versatility.The newly synthesized compounds have been characterized on the basis of their elementary analyses (C,N,H), and UV- and 1H-HMR-spectra.
- Himmelsbach, Frank,Schulz, Bernd S.,Trichtinger, Thomas,Charubala, Ramamurthy,Pfleiderer, Wolfgang
-
-
- REACTION OF NUCLEOBASES WITH α-ACETYLENIC ESTERS, POTENTIALLY USEFULL FOR CHEMICAL MODIFICATION OF NUCLEIC ACIDS
-
The NH2 group and the adjacent ring nitrogen of adenosine and cytidine react with α-acetylenic esters by addition across the triple bond and formation of a lactam with the ester group.
- Olomucki, M.,Gall, J. Y., Le,Colinart, S.,Durant, F.,Norberg, B.,Evrard, G.
-
p. 3471 - 3474
(2007/10/02)
-
- THE USE OF THE p-NITROPHENYLETHOXYCARBONYL GROUP FOR AMINO PROTECTION IN CYTIDINE AND ADENOSINE CHEMISTRY
-
Amino protection in 2'-deoxycytidine (1) and cytidine (2) as well as in 2'-deoxyadenosine (8) and adenosine (9) respectively can be achieved by the new reagents 1-(p-nitrophenylethoxycarbonyl)-benzotriazole (3) and 1-methyl-3-(p-nitrophenylethoxycarbonyl)-imidazolium chloride (7) to from the corresponding carbamates (4, 5, 13, 14) in high yields.
- Himmelsbach, Frank,Pfleiderer, Wolfgang
-
p. 3583 - 3586
(2007/10/02)
-
- PERMANGANATE OXIDATION OF N6,N6,8-TRISUBSTITUTED-2',3',5'-TRI-O-ACETYLADENOSINES
-
Oxidation of 2',3',5'-tri-O-acetyl derivatives of N6,N6-dialkyl-adenosines(3a-g) with KMnO4 in 50percent AcOH gave both the mono(5a-g) and didealkylderivati3es(6a-c) ; it was conclusiveoly proved that one and two methylene groups of the title nucleosides(3a-g) in the α position to the exocyclic nitrogen atom were simultaneously oxidized.
- Kato, Tetsuo,Ogawa, Shuichi,Ito, Isoo
-
p. 3205 - 3208
(2007/10/02)
-
- Studies on Organic Fluorine Compounds. Part 35. Trifluoromethylation of Pyrimidine- and Purine-nucleosides with Trifluoromethyl-Copper Complex
-
Halogenated nucleoside derivatives were trifluoromethylated using a solution of a trifluoromethyl-copper complex, which was prepared by shaking trifluoromethyl iodide and copper powder in hexamethylphosphoric triamide and filtering off the excess of copper powder.The following trifluoromethylated nucleosides were obtained in moderate to good yields: 5-trifluoromethyl-uridine, -deoxyuridine, -cytidine, -deoxycytidine, and arabinosylcytosine; 8-trifluoromethyl-adenosine, -deoxyadenosine, and -inosine; and 6-trifluoromethylribofuranosylpurine.This procedure offers simple synthesis of many trifluoromethyl compounds.
- Kobayashi, Yoshiro,Yamamoto, Kenjiro,Asai, Toyohira,Nakano, Masanori,Kumadaki, Itsumaro
-
p. 2755 - 2761
(2007/10/02)
-
