共查询到20条相似文献,搜索用时 15 毫秒
1.
Tokumi Maruyama Shigetada Kozai Mayuko Uchida 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):661-671
Abstract 1-Benzyluracils 2a,b were treated with iodobenzene in the presence of cuprous oxide in 2,4,6-trimethylpyridine at 180°C to give the N 1-phenyl derivatives 3a and 3b in 47% and 55%, respectively. Similar reaction of 2a with 2-bromopyridine at 120°C gave the 3-(2-pyridinyl)uracil 4a in 42% yield. However, unusual product 5 as well as 3-(2-pyridinyl) derivative 4b were obtained in the case of 2b. The structure of 5 was identified as 1-(2,6-difluorobenzyl)-3-[(2,4-dimethyl-2-pyridinyl)methyl]uracil from spectroscopic data. Reaction of the hypoxanthines 7a,b with 2-bromopyridine gave the 1-(2-pyridinyl)hypoxanthines 8a,b in low yields. But N-phenylation of 7a,b were unsuccessful. 相似文献
2.
Characterization of some new di- and trichlorinated phenylalanines synthesized via an acetamidomalonate condensation with the appropriate chlorinated benzyl halide is described. 相似文献
3.
Vasu Nair Sanjib Bera Travis Mickle Serge Van Calenbergh 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):577-579
Abstract Methodologies for the synthesis of novel isomeric dideoxynucleosides with unsaturation in the carbohydrate moiety have been developed. An example of the synthesis (Isod4A) is presented. Antiviral studies are in progress. 相似文献
4.
Vasu Nair Lawrence B. Zintek Geun S. Jeon 《Nucleosides, nucleotides & nucleic acids》2013,32(3-5):389-391
Abstract Approaches to the synthesis of (S) and (R) enantiomers of hydroxymethylated isodideoxynucleosides have been developed. Because of the symmetry introduced at the carbon that normally bears the -CH2OH group, these compounds have only one asymmetric center and each enantiomeric series may be viewed as being both D- and L- related. 相似文献
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Abstract The synthesis, stability toward nucleases, and conformational properties of 3′→5′ and 5′→5′ dinucleotides bearing an isomeric nucleoside component is described. 相似文献
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F. J. Lopez Aparicio F. Zorrilla Benitez F. Santoyo Gonzalez 《Carbohydrate research》1981,90(2):309-314
Thiodiglycolaldehyde (1) has been synthesised by dehydration of its hemialdal form, cis-2,6-dihydroxy-I,4-oxathiane (2a). The hydration and polymerisation of 1 have been studied. The composition and conformational population has been established for solutions of 2a in various solvents. In aqueous solution, 1,2a and its trans isomer 2b, and the acyclic dihydrate and monohydrate were detected. The preferred conformer of 2a has diequatorial OH groups 相似文献
8.
Vasu Nair Lawrence B. Zintek Pascal J. Bolon Todd B. Sells 《Nucleosides, nucleotides & nucleic acids》2013,32(3-5):385-388
Abstract The synthesis and anti-HIV activities of a number of new analogues of basetransposed chiral isomeric nucleosides are described. Modifications of the anti-HIV active compound, (S,S)-isodideoxyadenosine, included both the base and carbohydrate regions. 相似文献
9.
Iga Wasiak Aleksandra Kulikowska Magdalena Janczewska Magdalena Michalak Iwona A. Cymerman Andrzej Nagalski Peter Kallinger Wladyslaw W. Szymanski Tomasz Ciach 《PloS one》2016,11(1)
Dextran is widely exploited in medical products and as a component of drug-delivering nanoparticles (NPs). Here, we tested whether dextran can serve as the main substrate of NPs and form a stable backbone. We tested dextrans with several molecular masses under several synthesis conditions to optimize NP stability. The analysis of the obtained nanoparticles showed that dextran NPs that were synthesized from 70 kDa dextran with a 5% degree of oxidation of the polysaccharide chain and 50% substitution with dodecylamine formed a NP backbone composed of modified dextran subunits, the mean diameter of which in an aqueous environment was around 100 nm. Dextran NPs could be stored in a dry state and reassembled in water. Moreover, we found that different chemical moieties (e.g., drugs such as doxorubicin) can be attached to the dextran NPs via a pH-dependent bond that allows release of the drug with lowering pH. We conclude that dextran NPs are a promising nano drug carrier. 相似文献
10.
反义寡核苷酸可作为基因表达的抑制剂和潜在的治疗药物,但多种类型的寡核苷酸为聚阴离子化合物,难以跨过细胞膜.已知包括融合肽、信号肽在内的多种生物活性多肽具有跨膜与核定位能力.讨论了反义寡核苷酸-肽缀合物的合成和生物活性. 相似文献
11.
Lião LM Vieira PC Rodrigues-Filho E Fernandes JB Silva MF 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(3-4):403-406
An investigation of the MeOH extract from the roots of Peritassa campestris (Hippocrateaceae) afforded two isomeric seco-A-ring quinonemethide triterpenoids, campestrine-I (1) and -II (2). This appears to be the first report of a C26,-type triterpene carbon skeleton from the Celastraceae or Hippocrateaceae families. The structures were elucidated on the basis of spectral data, particularly HMQC, HMBC and NOE experiments. 相似文献
12.
The synthesis of a panel of oligosaccharides containing C-5 arabinofuranosyl residues (9-20) is described. These compounds are of interest as potential inhibitors of the alpha-(1-->5)-arabinosyltransferase involved in the assembly of mycobacterial cell-wall arabinan. In the series of compounds prepared, the 5-OH group on the nonreducing residue(s) is replaced, independently, with an amino, azido, fluoro, or methoxy functionality. The synthesis of the target compounds involved the preparation of a series of C-5 modified arabinofuranosyl thioglycosides (24-26) and their subsequent coupling to the appropriate acceptor species (21-23). Deprotection of the glycosylation products afforded the azido, fluoro, or methoxy analogs directly. The amino derivatives were obtained in one additional step by reduction of the azido compounds. 相似文献
13.
Abstract The synthesis of a homologues series of compounds related to (R, S)-isodideoxynucleosides has been completed by coupling a variety of natural purine and pyrimidine bases with a modified sugar intermediate. This sugar precursor was prepared regiospecifically and stereospecifically from D-glucose. 相似文献
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M. Nemer N. Thëriault A. Schifman K. K. Ogilvie 《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):257-258
Abstract Several symmetrically linked (3′-3′, 2′-2’ and 5′-5′) diribonucleoside monophosphates were prepared using the phosphodichloridite procedure. The 3′-3’ and 2′-2’ dimers showed unusual lability towards both acid and base due to the two hydroxyls adjacent to the phosphate moiety. 相似文献
16.
N. Sh. Padyukova H. B. F. Dixon E. V. Efimtseva B. S. Ermolinsky S. N. Mikhailov M. Ya. Karpeisky 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):1013-1014
Abstract Simple method for the preparation of anhydrides of nucleoside-5′-monophosphoric acid and with 1-hydroxyethane-1,1-diylbis(phosphonic acid) has been developed. 相似文献
17.
Han Yueh Hongchuan Yu Christopher S. Theile Ayan Pal Allen Horhota Nicholas Greco 《Nucleosides, nucleotides & nucleic acids》2013,32(9):661-679
Here, we present efficient syntheses of the R and S diastereomers of 8,5′-cyclo-2′-deoxyadenosine and 6,5′-cyclo-2′-deoxyuridine. We incorporated these interesting nucleosides into DNA to study how the cyclo linkage affects the stability of duplex formation. 相似文献
18.
Dang-Nan Zhou Lu Han Zhan Zhang Yun-Long Wang Xiao-Ping Zhang Yun-Jie Wu Gao-Lei Xi 《化学与生物多样性》2023,20(10):e202300620
Five psoralen derivatives were synthesized and the structures of them were characterized by 1H-NMR, 13C-NMR, and IR. The antioxidant properties of the compounds were tested by inhibiting the free radical-initiated DNA oxidation and scavenging the radical reaction. The results showed that the effective stoichiometric factors (n) of the compounds V and IV could reach 2.00 and 2.11 in the system of inhibiting the DNA oxidation reaction initiated by 2,2′-Azobis(2-methylpropionamidine) dihydrochloride (AAPH). In the inhibition of ⋅OH-oxidation of the DNA system, compounds I ~ V showed antioxidant properties. The thiobarbituric acid absorbance (TBARS) percentages of compounds IV and V were 76.19 % and 78.84 %. Compounds I ~ V could also inhibit Cu2+/GSH-oxidation of DNA, and all compounds exhibited good antioxidant properties except compound II (94.00 %). All the five compounds were able to trap diammonium 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) salt radical (ABTS+⋅), 2,2-diphenyl-1-picrylhydrazyl radical (DPPH⋅) and 2,6-di-tert-butyl-alpha-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-p-tolylox radical (galvinoxyl⋅). The ability of compounds I ~ V to scavenge those free radicals can be measured by the k values. The k values ranged from 0.07 to 0.82 in scavenging ABTS+⋅, galvinoxyl, and DPPH radicals, respectively. 相似文献
19.
Abstract 2,4-Dinitroaniline is an efficient intramolecular fluorescence-quencher for fluorescein - labeled oligonucleotides and interacts with the heterocyclic bases on duplex formation. Consequently, intramolecular fluorescence quenching is disturbed in double labeled oligonucleotides of this type, and fluorescein shows strong fluorescence in a duplex form. There is a substential increase of the fluorescence-quantum yield when the marker and quencher is attached to a single guanosine residue. Two kinds of doubly labeled oligonucleotides have been synthesized, using the NPE/NPEOC strategy. 相似文献
20.
Basova NE Kormilitsyn BN Perchenok AIu Rosengart EV Saakov VS Suvorov AA 《Ukrainski? biokhimicheski? zhurnal》2012,84(1):26-33
The isomeric-structure analysis data of anticholinesterase action of organophosphorous inhibitors with similar structure help in the search of specific effectors and detection of differences in reactivity of various animals' enzymes. This study compared the data of efficacy in respect of 4 mammal and 5 arthropoda cholinesterase preparations for 26 quinolizidine inhibitors, which molecules contain both the isomeric unbranched and branched alkoxyl radicals in the phosphoryl group, and the epimeric lupinine and epilupinine derivatives in the leaving group. The changes in the alkoxyl radical structure of inhibitor molecules act on their efficacy only with respect to the mammal enzymes ("group" inhibitor specificity). The differences between lupinine and epilupinine derivatives were revealed. Highly specific inhibitors of different enzymes were detected among the tested compounds. 相似文献