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271.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1117-1118
Abstract The efficient synthesis of oligonucleotides containing 2′-O-β-D-ribofuranosyl (and β-D-ribopyranosyl)nucleosides, 2′-O-α-D-arabinofuranosyl (and α-L-arabinofuranosyl)nucleosides, 2′-O-β-D-erythrofuranosylnucleosides, and 2′-O-(5′-amino-5-deoxy-β-D-ribofuranosyl)nucleosides have been developed. 相似文献
272.
《Nucleosides, nucleotides & nucleic acids》2013,32(5):813-822
A series of 2′ and 4′‐doubly branched carbocyclic nucleosides 15, 16, 17 and 18 were synthesized starting from simple acyclic ketone derivatives. The required 4′‐quaternary carbon was constructed using Claisen rearrangement. In addition, the installation of a methyl group in the 2′‐position was accomplished using a Grignard carbonyl addition of isopropenylmagnesium bromide. Bis‐vinyl was successfully cyclized using a Grubbs’ catalyst II. Natural bases (adenine, cytosine) were efficiently coupled by using Pd(0) catalyst. 相似文献
273.
Aymn E. Rashad Ahmed H. Shamroukh Randa E. Abdel-Megeid Ahmed Mostafa Mohamed A. Ali Klaus Banert 《Nucleosides, nucleotides & nucleic acids》2013,32(11-12):809-820
Treatment of 5-amino-1-(9-methyl-5,6-dihydronaphtho[1′,2′:4,5]thieno[2,3-d]pyrimidin-11-yl)-1H-pyrazole-4-carbonitrile (1) with formic acid afforded pyrazolo[3,4-d]pyrimidin-4-one derivative 2. The sodium salt of the latter compound (generated in situ) was treated with some alkyl halides to afford the corresponding N-substituted compounds 3–7. The siloxy derivative 8 (generated also in situ from 2) was ribosylated and glycosylated to yield compounds 9 and 11, respectively. Deprotection of compounds 9 and 11 in methanolic ammonia produced the free nucleosides 10 and 12, respectively. Moreover, the prepared compounds were tested for antiviral activity against H5N1 virus [A/chicken/Egypt/1/2006] and some of them revealed moderate results compared with the other tested compounds. 相似文献
274.
Luigi A. Agrofoglio Vincent Bezy Patrick Chaimbault Raphaël Delépée Boutaina Rhourri Philippe Morin 《Nucleosides, nucleotides & nucleic acids》2013,32(10-12):1523-1527
The intracellular analysis of the phosphorylated metabolites of some anti-HIV nucleosides by liquid chromatography or capillary electrophoresis coupled with tandem mass spectrometry (LC-MS/MS or CE-MS/MS) has been realized on human peripheral blood mononuclear cells (PBMC), with limit of quantitation (LOQ) that allow them to be quantitated intracellularly. We described also the analysis of modified urinary nucleosides as potential tumor biomarkers. 相似文献
275.
《Nucleosides, nucleotides & nucleic acids》2013,32(10):1899-1905
Abstract A convenient synthesis of 2′-deoxy-2-fluoroadenosine from commercially available 2-fluoroadenine is described. The coupling reaction of silylated 2-fluoroadenine with phenyl 3,5-bis[O-(t-butyldimethylsilyl)]-2-deoxy-1-thio-D-erythro-pentofuranoside gave the corresponding 2-fluoro-2′-deoxyadenosine derivative (α/β =1:1) in good yield. The α- and β-anomers were separated by chromatography, and then desilylated to give compounds 1a and 1b. 相似文献
276.
Abstract 9-(2-Acetoxyethoxy)methyl-N2-acetyl-6-thioguanine (2) undergoes two different transglycosylation reactions: i) the 7 ? 9 isomerization, which gives the respective 7-regioisomer (3) as the major product, ii) the 9 ? S6 glycosyl migration, which leads to a 9,S6-disubstituted product (4). S6-Methylation completely stopped the reversibility of transglycosylation. 相似文献
277.
D. Vannoni S. Giglioni A. Santoro E. Aceto E. Marinello R. Leoncini 《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):872-875
Adenosine kinase is an enzyme catalyzing the reaction: adenosine + ATP → AMP + ADP. We studied some biochemical properties not hitherto investigated and demonstrated that the reaction can be easily reversed when coupled with adenosine deaminase, which transforms adenosine into inosine and ammonia. The overall reaction is: AMP + ADP → ATP + inosine + NH3. The exoergonic ADA reaction shifts the equilibrium and fills the energy gap necessary for synthesis of ATP. This reaction could be used by cells under particular conditions of energy deficiency and, together with myokinase activity, may help to restore physiological ATP levels. 相似文献
278.
Srinivas Gadthula Chung K. Chu Raymond F. Schinazi 《Nucleosides, nucleotides & nucleic acids》2013,32(10-12):1707-1727
Since the discovery of 3′-azido-3′-deoxythymidine (AZT) and 2′,3′-didehydro-2′,3′-dideoxythymidine (d4T) as potent and selective inhibitors of the replication of human immunodeficiency virus (HIV), there has been a growing interest for the synthesis of 2′,3′-didehydro-2′,3′-dideoxynucleosides with electron withdrawing groups on the sugar moiety. Here we described an efficient method for the synthesis of such nucleoside analogs bearing structural features of both AZT and d4T. The key intermediate, 3-azido-1,2-bis-O-acetyl-5-O-benzoyl-3-deoxy-D-ribofuranose, 5 was synthesized from commercially available D-xylose in five steps, from which a series of pyrimidine and purine nucleosides were synthesized in high yields. The resultant protected nucleosides were converted to target nucleosides using appropriate chemical modifications. The final nucleosides were evaluated as potential anti-HIV agents. 相似文献
279.
《Nucleosides, nucleotides & nucleic acids》2013,32(12):2093-2104
Abstract A summary delineating the large scale synthetic studies to prepare labeled precursors of ribonucleosides-3′,4′,5′,5″- 2H 4 and -2′,3′,4′,5′,5″- 2H 5 from D-glucose is presented. The recycling of deuterium-labeled by-products has been devised to give a high overall yield of the intermediates and an expedient protocol has been elaborated for the conversion of 3-O-benzyl-α,β-D-allofuranose-3,4-d 2 6 to 1-O-methyl-3-O-benzyl-2-O-t-butyldimethylsilyl-α,β-D-ribofuranose-3,4,5,5′-d 4 16 (precursor of ribonucleosides-3′,4′,5′,5″- 2H 4 ) or to 1-O-methyl-3,5-di-O-benzyl-α,β-D-ribofuranose-3,4,5,5′-d 4 18 (precursor of ribonucleosides-3′,4′,5′,5″- 2H 4 ). 相似文献
280.
《Nucleosides, nucleotides & nucleic acids》2013,32(12):2145-2160
Abstract Alkylation of 6-chloropurine and 2-amino-6-chloropurine with bromoacetaldehyde diethyl acetal afforded 6-chloro-9-(2,2-diethoxyethyl)purine (3a) and its 2-amino congener (3b). Treatment of compounds 3 with primary and secondary amines gave the N6-substituted adenines (5a–5c) and 2,6-diaminopurines (5d–5f). Hydrolysis of 3 resulted in hypoxanthine (6a) and guanine (6b) derivatives, while their reaction with thiourea led to 6-sulfanylpurine (7a) and 2-amino-6-sulfanylpurine (7b) compounds. Treatment with diluted acid followed by potassium cyanide treatment and acid hydrolysis afforded 6-substituted 3-(purin-9-yl)- and 3-(2-aminopurin-9-yl)-2-hydroxypropanoic acids (8–10). Reaction of compounds 3 with malonic acid in aqueous solution gave exclusively the product of isomerisation, 6-substituted 4-(purin-9-yl)-3-butenoic acids (15). 相似文献