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1.
2'-Deoxy-2'-C-trifluoromethyl-beta-D-ribonucleoside derivatives bearing the five naturally occurring acid bases have been synthesized. All these derivatives were prepared by glycosylation reactions of purine and pyrimidine bases with a suitable peracylated 2-deoxy-2-C-trifluoromethyl sugar precursor to afford anomeric mixtures of protected nucleosides. After separation and deprotection, the resulting beta-nucleoside analogues were tested for their activity against HIV, HBV and several RNA viruses. However, none of these compounds showed significant antiviral activity nor cytotoxicity. 相似文献
2.
Hitherto unknown nucleoside analogues incorporating the five naturally occurring nucleic acid bases built on a 2-oxabicyclo[3.1.0]hexane template were synthesized. The synthesis of these new conformationally restricted nucleoside analogues involved the preparation of a suitable sugar precursor bearing the 2-oxabicyclo[3.1.0]hexane scaffold. This sugar was readily obtained from [(3aS,6aS)-2,2-dimethyl-3a,6a-dihydrofuro[2,3-d][1,3]dioxol-5-yl]methyl benzyl ether (4) following a Simons-Smith-type cyclopropanation reaction. Finally, glycosylation reactions and deprotection provided the nucleoside analogues. Using nucleoside 14 bearing thymine base as a model, we found that the conformation of such nucleoside analogue was restricted toward a (0)T(1) conformation. 相似文献
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Zavgorodnii S. G. Efimtseva E. V. Mikhailov S. N. Tsilevich T. L. Yavorskii A. É. Florent'ev V. L. 《Chemistry of Heterocyclic Compounds》1988,24(2):186-191
A convenient method for the synthesis of 1,5-dihydroxy-3-oxa-2-pentyl derivatives of nucleic bases, which consists in the condensation of trimethylsilyl derivatives of nucleic bases with 1,2,5-triacetoxy-3-oxapentane in the presence of SnCl4, is proposed. Optically active derivatives — (R)- and (S)-1-(1,5-dihydroxy-3-oxa-2-pentyl)uracil, respectively — were obtained by periodate oxidation of -L- and -D-arabinopyranosyluracil.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 223–228, February, 1988. 相似文献
6.
C. G. Overberger Yoshiaki Inaki 《Journal of polymer science. Part A, Polymer chemistry》1979,17(6):1739-1758
Graft copolymers of nucleic acid bases and L-α-amino acids on polyethyleneimine were synthesized, and carboxyl derivatives of adenine and thymine were grafted by the p-nitrophenyl ester method onto linear and branched polyethyleneimine. The carboxyl derivatives of nucleic acid bases were also grafted onto the monomeric graft copolymers of L -α-amino acids on polyethyleneimine; the carboxyl derivatives were obtained by the condensation of polyethyleneimine with L -α-amino acids with a coupling agent. 相似文献
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Jurij Svete Branko Stanovnik Miha Tiler Ljubo Goli
Ivan Leban 《Journal of heterocyclic chemistry》1989,26(1):145-153
From heteroarylaminomethyleneoxazolones 4 , obtained from N-heteroarylformamidines 2 and 2-phenyl-5-oxo-4,5-dihydro-1,3-oxazole ( 3 ), the following β-heteroarylamino-α,β-dehydro-α-amino acid derivatives were prepared: methyl 8 and ethyl esters 9 , amides 10 and 11 , hydrazides 12 , and azides 15 . By catalytic hydrogenation the compounds 4 were converted into β-heteroarylamino substituted amides 18 and β-heteroarylamino-α-amino acids 20 . 相似文献
10.
The preparation of N1 (2,3-O-isopropylidene-β-D-ribofuranosyl)-4-quinazolone ( 6 ) and N3-β-D-ribofuranosyI-4-quinazolone ( 3b ) are reported. The N3 derivative was prepared by the direct condensation of 4-trimethylsilyloxyquinazoline ( 2 ) and 2,3,5-tri-O-benzoyl- D - ribofuranosyl bromide. The N1 derivative was prepared from the previously reported N1 -β-D-ribofuranosyl-2,4-quinazolinedione via the cyclonucleoside 4 . 相似文献
11.
Henryk Wincel 《Journal of the American Society for Mass Spectrometry》2009,20(10):1900-1905
Thermochemical data, ΔH
n
o
, ΔS
n
o
, and ΔG
n
o
, for the hydration of protonated nucleic acid bases and protonated nucleosides have been experimentally studied by equilibrium
measurements using an electrospray high-pressure mass spectrometer equipped with a pulsed ion-beam reaction chamber. For protonated
nucleobases the hydration enthalpies were found to be similar for all studied systems and varied between 12.4–13.1 kcal/mol
for the first and 11.2–11.5 kcal/mol for the second water molecule. While for protonated nucleosides the water binding enthalpies
(11.7–13.3 kcal/mol) are very close to those for protonated nucleobases, the entropy values are “more negative.” The structural
and energetic aspects of hydrated ions are discussed in conjunction with the available theoretical data. 相似文献
12.
A concise and efficient synthesis of α,α′,β-trisubstituted β-lactones is presented. These novel lactones are easily obtained in five steps and will be dedicated to anionic ring opening polymerization. 相似文献
13.
Alan R. Katritzky Maria Szajda Jamshed N. Lam 《Journal of heterocyclic chemistry》1993,30(5):1261-1265
N-Methyl-2-methyl-3-(benzotriazol-l-yl)propanamide, on treatment with butyllithium forms a dianion which on treatment with alkyl and benzyl halides, aldehydes and ketones affords monosubstituted products; with ethyl p-toluate, a lactam is formed. The alkylated derivatives eliminate benzotriazole in the presence of base to afford trisubstituted α,β-unsaturated amides. 相似文献
14.
Five β‐peptide thioesters ( 1 – 5 , containing 3, 4, 10 residues) were prepared by manual solid‐phase synthesis and purified by reverse‐phase preparative HPLC. A β‐undecapeptide ( 6 ) and an α‐undecapeptide ( 7 ) with N‐terminal β3‐HCys and Cys residues were prepared by manual and machine synthesis, respectively. Coupling of the thioesters with the cysteine derivatives in the presence of PhSH (Scheme and Fig. 1) in aqueous solution occurred smoothly and quantitatively. Pentadeca‐ and heneicosapeptides ( 8 – 10 ) were isolated, after preparative RP‐HPLC purification, in yields of up to 60%. Thus, the so‐called native chemical ligation works well with β‐peptides, producing larger β3‐ and α/β3‐mixed peptides. Compounds 1 – 10 were characterized by high‐resolution mass spectrometry (HR‐MS) and by CD spectroscopy, including temperature and concentration dependence. β‐Peptide 9 with 21 residues shows an intense negative Cotton effect near 210 nm but no zero‐crossing above 190 nm, (Figs. 2–4), which is characteristic of β‐peptidic 314‐helical structures. Comparison of the CD spectra of the mixed α/β‐pentadecapeptide ( 10 ) and a helical α‐peptide (Fig. 5) indicate the presence of an α‐peptidic 3.613 helix. 相似文献
15.
Tetra-O-benzyl--D-glucopyranosyl bromide in dichloromethane reacts stereospecifically with solutions of phenols in aqueous sodium or potassium hydroxide, in the presence of phase transfer catalysts, to give good yields of tetra-O-benzyl aryl-β-D-glucopyranosides which are converted into the corresponding aryl β-D-glucopyranosiduronic acids by sequential catalytic debenzylation and catalytic oxidation. 相似文献
16.
Dominique Fasseur Pascal Cauliez Daniel Couturier Benoît Rigo Sebastien Defretin 《Journal of heterocyclic chemistry》1994,31(4):829-835
In the pyroglutamic acid series, β-enaminoesters 3 were formed in the 2-position by opening of the corresponding Meldrum's derivative 6 , and β-enaminonitriles 4 were obtained by treating carbamate vinylogous 5 by trimethytsilyl iodide. Alkylation and acylation of β-enaminoester 3a was briefly examined. 相似文献
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A substitute for the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturated aldehydes employing sulfur ylides is described. The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde. High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in the conversion of β-ionone into the β-C14-aldehyde, a key intermediate in the Isler synthesis of vitamin A. The efficient preparation of α- and β-cyclocitral by the novel process is also described. 相似文献
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M. S. Marthas S. G. Amin H. P. S. Chawk Ajay K. Bose 《Journal of heterocyclic chemistry》1978,15(4):601-604
A convenient synthesis of α-hydroxy-β-lactams has been devised that involves the annelation of an inline with benzyloxyacetyl chloride and triethylamine and subsequent hydrogenolysis in the presence of palladium on carbon. In most cases a cis-β-lactam was obtained. A thioimidate can also be used as the imino component in the annelation reaction but the hydrogenolysis step fails. The annelation of the appropriate thiazoline to a 6-epi-penicillin derivative occurred much more readily with benzyloxyacetyl chloride than with azidoacetyl chloride. 相似文献