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1.
Vera Cheng Lawrence Hughes Vivian B. Griffin Roland Montserret Abraham P. Ollapally 《Nucleosides, nucleotides & nucleic acids》2013,32(2):223-228
Abstract Synthesis of 1-(2, 3, 4-tri-0-acetyl-α-L-rhamnopyranosyl) uracil (3), 1-(α-L-rhamnopyranosyl) uracil (4), 1-(2, 3-0-isopropylidene-α-L-rhamnosyl) uracil (5), and 1-(2, 3-0-isopropylidene-4-keto-α-L-rhamnopyranosyl) uracil (6) are reported. Oxidation of (5) to (6) was effected using pyridinium chlorochromate in presence of molecular sieves. 相似文献
2.
Krzysztof W. Pankiewicz Kyoichi A. Watanabe 《Nucleosides, nucleotides & nucleic acids》2013,32(5):613-624
Abstract Treatment of ψ-uridine (3) with α-acetoxyisobutyryl chloride in acetonitrile gave, after deprotection, a mixture of four products: 5-(2-chloro-2-deoxy-β-D-arabinofuranosyl)uracil (10a), its 3′-chloro xylo isomer (11a), 2′-chloro-2′-deoxy-ψ-uridine (9a) and 4,2′-anhydro-ψ-uridine (8a). Each component was isolated by column chromatography. Compound 9 was converted to the known 1,3-dimethyl derivative 2 by treatment with DMF-dimethylacetal. Treatment of 10 and 11 with NaOMe/MeOH afforded the same 4,2′-anhydro-C-nucleoside 8. The 1,3-dimethyl analogues of 10 and 11, however, were converted to 2′,3′-anhydro-1,3-dimethyl-ψ-uridine (13) upon base treatment. The epoxide 13 was also prepared in good yield by treatment of 10 and 11 with DMF-dimethylacetal. 相似文献
3.
Sung K. Kim Richard W. Fuller Victor E. Marquez 《Nucleosides, nucleotides & nucleic acids》2013,32(5):663-677
Abstract The cytosine analogue of Neplanocin A, cyclopentenyl cytosine (CPE-C, 4), has significant antitumor and antiviral activity. Two closely related analogues modified at the 2′-position, ara-CPE-C (6) and 2′-deoxy-CPE-C (5), have been synthesized from the corresponding uracil derivative CPE-U. Both compounds were devoid of cytotoxicity against L1210 leukemia in vitro. Ara-CPE-C displayed antiviral activity against influenza type A2 but was not very potent. 相似文献
4.
James L. Kelley James A. Linn Lilia Beauchamp Peter Collins J. W. T. Selway Karen K. Biron 《Nucleosides, nucleotides & nucleic acids》2013,32(4):475-489
Abstract The synthesis and antiherpetic activity of 9-[[[2-hydroxy-1-(hydroxymethyl)ethyl]thio]methy1]guanine (4) and 1-[[[2-hydroxy-1-(hydroxymethyl)ethyl]thio]methy]cytosine (6), the side-chain thio analogues of ganciclovir (3) and BW A1117U (5), are described. The sidechain synthon 1,3-bis(benzyloxy)-2-[(chloromethyl)thio]propane (11) was prepared in four steps from 1,3-bis(benzyloxy)-2-propanol (7). Alkylation of 2-amino-6-chloro-9H-purine with 11 provided the intermediate 9-substituted-2-amino-6-chloropurine 12, which was conveniently converted to 4 in two steps. Reaction of a fivefold excess of cytosine with 11 provided the desired 1-isomer 14, which was debenzylated to give 6. In contrast with ganciclovir (3) and BW A1117U (5), neither 4 nor 6 had significant in vitro activity against human cytomegalovirus. 相似文献
5.
Abstract The reaction of the 2′,3′-lyxoepoxide (1) with ammonium azide gives two products; namely, the 3′-arabino azide (2a) and in low yield 2′-xylo azide (3a). After debenzoylation and reduction the resulting mixture of amines was resolved by chromatography on a weak cation exchanger, Amberlite IRC-50, and afforded crystalline 1-(3-amino-3-deoxy-β-D-arabinofuranosyl)uracil (2c) and 1-(2-amino-2-deoxy-β-D-xylofuranosyl)uracil (3c) in the ratio of 4:1. 相似文献
6.
Tai-Shun Lin Shi-Ping Xu Mao-Chin Liu William R. Mancini 《Nucleosides, nucleotides & nucleic acids》2013,32(4):559-568
Abstract Optically pure (R)- and (S)-1-[[2-hydroxy-1-(aminomethyl) ethoxy]methyl]-5-benzyluracil [(R)-AHPBU and (S)-AHPBU, respectively], two potent uridine phosphorylase inhibitors, have been synthesized via multi-step syntheses starting from independent chiral compounds. The activity of (R)-AHPBU, (S)-AHPBU, and (R,S-AHPBU which have been previously synthesized, on the inhibition of uridine phosphorylase from Sarcoma-180 cells has been studied and compared. The K. values for (R,S)-, (R)- and (S)-AHPBU were determined to be 15·2.3, 17·2.7 and 16·2.0 nM, respectively. This indicates that (R) and (S) optical enantiomers have the same affinity for binding to uridine phosphorylase. These acyclic pyrimidine amino nucleoside analogues represent a new class of potent uridine phosphorylase inhibitors, which has a bulky hydrophobic substituent at the 5-position in the uracil base, yet has remarkably high water solubility. 相似文献
7.
Summary An investigation of plasmid stability in aSaccharomyces cerevisiae double mutant has been performed. The host was a double recombinantura3
furl mutant containing a plasmid bearing the yeast URA3+ allele and an expression cassette for human 1-antitrypsin. The mutant was grown in continuous culture employing a semi-defined medium containing added uracil to provide non selective growth conditions. After 150 generations of continuous growth, no cured cells had been detected: the specific expression level of 1-antitrypsin remained constant throughout the experiment. 相似文献
8.
Abstract Treatment of D-xylose (1) with 0.5% methanolic hydrogen chloride under controlled conditions followed by benzoylation and acetolysis afforded crystalline 1-O-acetyl-2, 3, 5-tri-O-benzoyl-α-D-xylofuranose (4) in good yield. Coupling of 4 with 2, 4-bis-trimethylsilyl derivatives of 5-alkyluracils (methyl, ethyl, propyl and butyl) (5a-5d), 5-fluorouracil (5e) and uracil (5f) in acetonitrile in the presence of stannic chloride gave 1-(2,3,5-tri-O-benzoyl-β-D-xylofuranosyl)-nucleosides (6a-6f). Saponification of 6 with sodium methoxide afforded 1-β-D-xylofuranosyl-5-substituted uracils (7a-7f). Condensation of 4 with free adenine in similar fashion and deblocking gave carcinostatic 9-β-D-xylofuranosyladenine (7g). 相似文献
9.
Jiro Kondo Tanashaya Ciengshin Ella Czarina Magat Juan Yoshiteru Sato Kenta Mitomi Satoru Shimizu 《Nucleosides, nucleotides & nucleic acids》2013,32(4-6):693-704
DNA fragments with the sequences d(gcGX[Y]n Agc) (n = 1, X = A, and Y = A, T, or G) form base-intercalated duplexes, which is a basic unit for formation of multiplexes such as octaplex and hexaplex. To examine the stability of multiplexes, a DNA with X = Y = G and n = 1 was crystallized under conditions different from those of the previously determined sequences, and its crystal structure has been determined. The two strands are coupled in an anti-parallel fashion to form a base-intercalated duplex, in which the first and second residues form Watson-Crick type G:C pairs and the third and sixth residues form a sheared G:A pairs at both ends of the duplex. The G4 and G5 bases are stacked alternatively on those of the counter strand to form a long G column of G3-G4-G5*-G5-G4*-G3*, the central four Gs being protruded. In addition, the three duplexes are associated to form a hexaplex around a mixture of calcium and sodium cations on the crystallographic threefold axis. These structural features are similar to those of the previous crystals, though slightly different in detail. The present study indicates that mutation at the 4th position is possible to occur in a base-intercalated duplex for multiplex formations, suggesting that DNA fragments with any sequence sandwiched between the two triplets gcG and Agc can form a multiplex. 相似文献
10.
Kwasi Agyei-aye Shijia Yan Anna K. Hebbler David C. Baker 《Nucleosides, nucleotides & nucleic acids》2013,32(3):327-337
Abstract 2,3′-Anhydro-2′-deoxy-5′-0-(triphenyl methyl) and 5′-0-(monomethoxytriphenylmethyl) pyrimidine nucleosides of uracil, thymine, and cytosine were synthesized in a single step from their 2′-deoxy-5′-0-(triphenylmethyl) or 5′-0-(monomethoxytriphenylmethyl) precursors using N,N-diethylaminosulfur trifluoride (DAST). The anhydronucleosides were either isolated or directly converted to their respective 2-deoxy-β-D-threo-pentofuranosyl nucleosides using sodium hydroxide in ethanol. 相似文献
11.
Jiří žemlička 《Nucleosides, nucleotides & nucleic acids》2013,32(3):245-264
Abstract New analogues of antiviral agents 9-(2, 3-dihy-droxyproply) adenine (DHPA, 1a.) and 9-(2-hydroxyethoxymethyl) guanine (acyclovir, Ib) - compounds Ic and Id were prepared and their biological activity was investigated. Racemic 1, 2, 4-butanetriol (2) was converted to the corresponding benzylidene derivative (3a) by acetalation with benzalde-hyde and triethyl orthoformate. Acetal 3a and p-toluene- sul-fonyl chloride in pyridine gave the corresponding p-toluenes fonate 3b. Alkylation of adenine 5a via sodium salt of 5a with 3b in dimethylformamide or in the presence of tetra-n-butylammonium fluoride in tetrahydrofuran gave intermediate 6a. Reaction of 2-amino-6-chloropurine (5b) with 3b effected by K2CO3 in dimethylsulfoxide gave compound 6b and a smaller amount of 7-alkylated proauct 7. A similar transformation catalyzed by tetra-n-butylammonium fluoride afforded only intermediate 5b. Acid-catalyzed de-protection (hydrolysis) of 6b and 6a gave the title compounds Ic and Id. The S-enantiomer of Ic was deaminated with adenosine deaminase. Our results argue against the presence of a methyl group-binding site of adenosine deaminase. Compounds Ic and Id exhibited little or no activity in antiviral assays with several DNA and RNA viruses. 相似文献
12.
Yogesh S. Sanghvi Krishna G. Upadhya N. Kent Dalley Roland K. Robins Ganapathi R. Revankar 《Nucleosides, nucleotides & nucleic acids》2013,32(4):737-759
Abstract Several 4-substituted-1-β-D-ribofuranosyl-3-hydroxypyrazoles were prepared as structural analogs of pyrazofurin. Glycosylation of the TMS derivative of ethyl 3(5)-hydroxypyrazole-4-carboxylate (3) with 1-0-acetyl-2,3,5-tri-0-benzoyl-D-ribofuranose in the presence of TMS-triflate gave predominantly ethyl 3-hydroxy-1-(2,3,5-tri-0-benzoyl-β-D-ribofuranosyl)pyrazole-4-carboxylate (4a), which on subsequent ammonolysis furnished 3-hydroxy-1-β-D-ribofuranosylpyrazole-4-carboxamide (5). Benzylation of 4a with benzyl bromide and further ammonolysis gave 3-benzyloxy-1-β-D-ribofuranosylpyrazole-4-carboxamide (8a). Catalytic (Pd/C) hydrogenation of 8a afforded yet another high yield route to 5. Saponification of the ester function of ethyl 3-benzyloxy-1-β-D-ribofuranosylpyrazole-4-carboxylate (7b) gave the corresponding 4-carboxylic acid (6a). Phosphorylation of 8a and subsequent debenzylation of the intermediate 11a gave 3-hydroxy-1-β-D-ribofuranosylpyrazole-4-carboxamide 5′-phosphate (11b). Dehydration of 3-benzyloxy-1-(2,3,5-tri-0-acetyl-β-D-ribofuranosyl)pyrazole-4-carboxamide (8b) with POCl3 provided the corresponding 4-carbonitrile derivative (10a), which on debenzylation with Cl3SiI gave 3-hydroxy-1-(2,3,5-tri-0-acetyl-β-D-ribofuranosyl)pyrazole-4-carbonitrile (13). Reaction of 13 with H2S/pyridine and subsequent deacetylation gave 3-hydroxy-1-β-D-ribofuranosylpyrazole-4-thiocarboxamide (12b). Similarly, treatment of 13 with NH2OH afforded 3-hydroxy-1-β-D-ribofuranosylpyrazole-4-carboxamidoxime (14a), which on catalytic (Pd/C) hydrogenation gave the corresponding 4-carboxamidine derivative (14b). The structural assignment of these pyrazole ribonucleosides was made by single-crystal X-ray analysis of 6a. None of these compounds exhibited any significant antitumor or antiviral activity in cell culture. 相似文献
13.
S. Juntunen H. Essadiq A. Grouiller J. Chattopadhyaya 《Nucleosides, nucleotides & nucleic acids》2013,32(1-2):187-189
Abstract New routes to the preparations of 2′-deoxy-3′-C-methyl uridine (2c) and 1-(5′-0-trityl-3′-deoxy-β-D-glycero-pentofuran-2-ulosyl)uracil (4) from 5′-0-trityl-2′-0-tosyl uridine (1) and 5′-0-trityl-3′-0-tosyl uridine (3) respectively are described. 相似文献
14.
Sequence and conformational effects on imino proton exchange in A.T- and A.U-containing DNA and RNA duplexes 总被引:2,自引:0,他引:2
1H-nmr relaxation has been used to study the effect of sequence and conformation on imino proton exchange in adenine–thymine (A · T) and adenine–uracil (A · U) containing DNA and RNA duplexes. At low temperature, relaxation is caused by dipolar interactions between the imino and the adenine amino and AH2 protons, and at higher temperature, by exchange with the solvent protons. Although room temperature exchange rates vary between 3 and 12s?1, the exchange activation energies (Eα) are insensitive to changes in the duplex sequence (alternating vs homopolymer duplexes), the conformation (B-form DNA vs A-form RNA), and the identity of the pyrimidine base (thymine vs uracil). The average value of the activation energy for the five duplexes studied, poly[d(A-T)], poly[d(A) · d(T)], poly[d(A-U)], Poly[d(A) · d(U)], and poly[r(A) · r(U)], was 16.8 ± 1.3 kcal/mol. In addition, we find that the average Eα for the A.T base pairs in a 43-base-pair restriction fragment is 16.4 ± 1.0 kcal/mol. This result is to be contrasted with the observation that the Eα of cytosine-containing duplexes depends on the sequence, conformation, and substituent groups on the purine and pyrimidine bases. Taken together, the data indicate that there is a common low-energy pathway for the escape of the thymine (uracil) imino protons from the double helix. The absolute values of the exchange rates in the simple sequence polymers are typically 3–10 times faster than in DNAs containing both A · T and G · C base pairs. 相似文献
15.
16.
Abstract R P and S P phosphorus diastereoisomers of the title compound (2) are prepared from the corresponding cyclic monophosphate. Solution conformation of the dioxaphosphor-inane ring and hydrolysis of R p-2 and S p-2 are studied and compared with those of the phosphorus diastereoisomers of the isomeric compound that contains the 5′-methyl group in the axial position. 相似文献
17.
18.
Guy Tourigny Allan L. Stuart Irena Ekiel Philip J. Aduma Sagar V. Gupta 《Nucleosides, nucleotides & nucleic acids》2013,32(7):1189-1200
Abstract The molecular conformations of 3′- and 5′-azido and amino derivatives of 5-methoxymethyl-2′-deoxyuridine, 1, were investigated by nmr. The glycosidic conformation of 5-methoxymethyl-5′-amino-2′,5′-dideoxy-uridine, 5 had a considerable population of the syn form. The 5′-derivatives show a preference for the S conformation of the furanose ring as in 1. In contrast, the 3′-derivatives show preference for the N conformation. For 5-methoxymethyl-3′-amino-2′,3′-dideoxyuridine, 3, the shift towards the N state is pH dependent. The preferred conformation for the exocyclic (C4′,C5′) side chain is g+ for all compounds except 5 which has a strong preference for the t rotamer (79%). Compounds 1, 3 and 5 inhibited growth of HSV-1 by 50% at 2, 18 and 70 μg/ml respectively, whereas 2 and 4 were not active up to 256 μg/ml (highest concentration tested). The compounds were not cytotoxic up to 3,000 μM. 相似文献
19.
Sunil Dutta Soni T Srikrishnant J L. Alderfer 《Nucleosides, nucleotides & nucleic acids》2013,32(11-12):1945-1957
Abstract The stereochemistry and the conformational equilibria of 5-fluorocytidine (5FCyd) have been determined by X-ray crystallography and correlated with NMR spectroscopy in the solution state. Crystals of 5FCyd have unit cell dimensions a=9.854(1), b=l5.012(2), c=15.290(2)Å, α=β=γ=90° with two molecules in the asymmetric unit. Both molecules are in the anti-conformation, C3′-endo sugar pucker and a ? (C4′-C5′) of g+. The two molecules in the asymmetric unit show slight variation in their bond distances and bond angles but their overall solid state conformation is similar. The NMR results indicate the 5FCyd has an anti-conformation, a mixed sugar pucker of 36% C2′- endo and 64% C3′-endo and an exocyclic furanose conformation (?) of 74%(g+), 19%(t) and 7%(g?). Certain purine and pyrimidine analogues readily replace the natural bases in nucleic acid if they are present during replication. Halogenated nucleic acids have been known for the past thirty years when for the first time it was found that 5-iodouracil could be incorporated into the nucleic acid of E coli 1. This provided the basis for the synthesis of 5-fluoro-nucleic acid bases and their use as a chemotherapeutic agent. The biological properties of 5-halogenated uracil derivatives have been examined in detail. The incorporation of the halogenated base into mRNA could lead to errors in the reading frame which would alter the phenotype without permanent change in DNA genotype2-4, also, it can substitute for uracil into mRNA and may exert a mutagenic effect5 or can occasionally lead to the production of altered protein6-7. A substitution of uracil by fluorouracil in the mRNA and a preferential pairing of the 5FUra with a guanosine in the tRNA anti-codons can account for the first substitution. This is because 5FU assumes properties similar to cytosine when the base ionizes. This occurs readily for 5FU (pKa = 7.8) due to the electronegative fluorine atom at C5 instead of hydrogen. 5FCyd shows antifungal activity against Saccharomyces cerevisiae and Candida species. It is the drug of choice for systemic infections. In order to obtain a more basic understanding of the potential of such processes, the present study was undertaken as the first step using solid phase study by X-ray crystallography and its structure in solution by NMR spectroscopy8. 相似文献
20.
Abstract The composition of the products of reaction of 1-(2,3-anhydro-5-O-benzoyl-β-D-lyxofuranosyl)uracil (1) with NH4N3 was studied by a reverse-phase HPLC system which was found to separate the 3-azido-arabino 2 and 2-azido-xylo 3 isomers that were formed. The use of a 10:1 ratio of NH4N3 to 1 in refluxing EtOH was found to minimize ring opening at C-2 (7%). The higher stereoselectivity of ring opening produced by using a large excess of NH4N3 was suppressed by conducting the reaction in DMF. Preventing the escape of the NH3 by-product only resulted in debenzoylation. The isolation of pure, crystalline 3 was achieved by reverse-phase preparative HPLC. Separation from the arabino isomer was also effected by debenzoylation and selective acetonide formation with the xylo isomer, which allowed facile isolation of the latter by normal phase chromatography. Hydrolysis of the acetonide 7 provided unprotected 2-azido-xylo nucleoside 6, which was also obtained by NaOMe treatment of 3. The mechanistic basis for the stereo-selectivity of epoxide opening is discussed. 相似文献