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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 57 (1992), S. 7300-7308 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 2195-2202 
    ISSN: 0947-3440
    Keywords: AZT ; Nucleoside α-hydroxybenzylphosphonates ; Phosphonate-phosphate rearrangement ; Prodrugs ; HIV chemotherapy ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The α-hydroxybenzylphosphonates 1a-1j of the antiviral drug 3′-azido-2′,3′-dideoxythymidine 5 (AZT) as potential lipophilic prodrugs were readily accessible in 49% to 87% yield via a four-step synthetic pathway introducing the modifications in the aromatic ring system in the last step by making use of intermediate 6. All compounds 1a-1j exhibited higher partition coefficients in 1-octanol/water than AZT (5). In hydrolysis studies at pH 7.5 we observed that precursors to bioactive compounds were delivered by simple hydrolysis of the lipophilic precursors 1a-1j via two different mechanisms: the phosphonate-phosphate rearrangement leading to the benzylphosphotriesters 2 and/or the direct cleavage into the di-AZT phosphonate 6. Both compounds 2 and 6 were further degraded yielding the potentially antiviral active compounds 4 and 8, respectively. The hydrolysis pathway could be controlled by the substitution pattern in the benzylic moiety. Identical hydrolytic behavior of 1 was detected in „biological“ hydrolysis kinetics by using a RPMI culture medium containing 10% heat-inactivated fetal calf serum (FCS). The title compounds 1a-1j exhibited considerable HIV-1 and HIV-2 activity in wild-type CEM/O cells.
    Additional Material: 2 Tab.
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  • 3
    ISSN: 0947-3440
    Keywords: 5′,5′-O-Di-AZT-O′-benzylphosphotriester ; Homo-dinucleoside prodrugs ; Anti-HIV chemotherapy ; Nucleoside monophosphate ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 5′,5′-O-di-(3′-azido-2′,3′-dideoxythymidinyl)-O′-benzylphosphotriesters 1 as potential prodrugs of nucleoside monophosphates is described. The concept is applied to the antiretroviral nucleoside analog 3′-azido-2′,3′-deoxythymidine (AZT) 4. All derivatives 1 were synthesized by reaction of the tetra-n-butylammonium salt of di-AZT-phosphate 2b with different benzyl bromides or -chlorides 9. Compound 2b was obtained by a combination of phosphoamidite/H-phosphonate chemistry, subsequent oxidation to 2a, and cation exchange. The partition coefficients of 1 in an 1-octanol/water mixture show that all compounds exhibit a much higher lipophilicity than the parent nucleoside AZT (4). It was also shown, that 1 decomposes spontaneously under mild aqueous basic conditions (phosphate buffer (pH 7.5) and RPMI culture medium containing heat-deactivated fetal calf serum) releasing selectively the di-AZT phosphate anion 2. The half-lives of 1 could be adjusted within a wide range by changing the ring substituents of the benzyl group. Additionally, the mechanism of hydrolysis varies if the substituent is changed from a donor to an acceptor one. The described phosphotriesters 1 exhibit considerable antiviral activity in HIV-1- and HIV-2-infected CEM/O cells, whereas no activity was detected in the HIV-2-infected thymidine kinase-deficient CEM cell line. On the other hand, we could not detect any cytotoxicity of the described phosphotriesters. Consequently, compounds 1 should act as prodrugs or depot forms at least of antiviral nucleoside analogs.
    Additional Material: 2 Tab.
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  • 4
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 107 (1995), S. 1790-1791 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 6
    ISSN: 0044-8249
    Keywords: AIDS ; Chemotherapie ; Phosphotriester-Prodrugs ; Prodrugs ; Thymidinderivate ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 837-846 
    ISSN: 1434-193X
    Keywords: AZT ; cycloSal-pro-nucleotide ; Prodrugs ; Nucleotide delivery ; HIV chemotherapy ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of our cycloSaligenyl- (cycloSal) pronucleotide concept to the approved anti-HIV dideoxynucleoside 3′-azido-3′-deoxythymidine AZT (1) is reported. This pro-nucleotide concept has been designed to deliver the corresponding 3′-azido-3′-deoxythymidine monophosphate AZTMP (2) by selective chemical hydrolysis from the lipophilic precursors cycloSal-AZTMP 4a-h. All derivatives 4a-h were synthesized using differently substituted salicyl alcohols 7a-h as starting materials. In hydrolysis studies, compounds 4 decomposed selectively releasing AZTMP (2) and the salicyl alcohols 7 following the designed tandem reaction. Furthermore, due to the electronic properties introduced by substituents, the half-lives of the triesters 4 could be ajusted over a wide range. Phosphotriesters 4 exhibited considerable biological activity in HIV-1 and HIV-2 infected wild-type human T-lymphocyte (CEM/O) cells, whereas, contrary to our expectations, nearly all activity was lost in HIV-2 infected thymidine-kinase-deficient CEM cells.
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  • 8
    ISSN: 0947-3440
    Keywords: Phosphonates, α-hydroxyarylmethyl, α-, β- and γ-Hydroxyalkyl- ; 2-n-Butyloxazaborolidine catalysis ; Enantioselective reduction ; Keto phosphonates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantioselective synthesis of α-hydroxyarylmethylphosphonates 2a-p by the oxazaborolidine-catalyzed reduction of α-keto phosphonates 1a-p using different boranes 4a-c was studied in detail. Moderate to good enantioselectivities are found (up to 80% ee) by using the borane-dimethyl sulfide complex 4a as reducing reagent and the 2-n-butyl derivative of the (S)-5,5-diphenyl-3,4-trimethylene-1,3,2-oxazaborolidine catalyst 3b. In contrast, excellent enantiomeric excesses (up to 99% ee) as well as high chemical yields are obtained when catecholborane 4c in combination with low temperature is introduced. Substituent effects on the starting material 1 are discussed with the help of structural information obtained by X-ray analyses of the benzoylphosphonates 11fγ, 1jγ, and 1nγ. A slight decrease in enantioselectivity was found within the series of α-, β-, and γ-hydroxyalkylphosphonates 6, 8, and 10, respectively. Nevertheless, even these compounds are reduced with enantioselectivities ranging from 68% (10) to 95% (6) by using catecholborane 4c and catalyst 3b. On the other hand, we synthesized the allylic α-hydroxyphosphonate 12 in 75% chemical yield and with 56% enantiomeric excess by means of this methodology. The reaction has subsequently been applied to the synthesis of α-hydroxyalkylphosphonates 14a-c, which were obtained with ee values up to 90%. Compounds 14 are useful precursors for the synthesis of the P-amino acids 15.
    Additional Material: 6 Tab.
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  • 9
    ISSN: 0009-2940
    Keywords: O-α-aminoacylation, activation of aromatic amines by ; Bionucleophiles, model reactions with ; N-[(Deoxy)guanosine-8-yl]arylamine adducts of monocyclic aromatic amines ; 8-(4-Methylanilino)-5′-guanosinemonophosphate, in-vitro-formation of ; Phenacetin, analog of the ultimate carcinogen ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Aryl-O-(α-aminoacyl)hydroxylamine: Model Reactions with Deoxyguanosine, Guanosine and 5′-Guanosinemonophosphate for the Activation of Monocyclic Aromatic Amines (e.g. Phenacetin) into Ultimate CarcinogensIn in vitro model reactions of the activation of monocyclic aromatic amines by α-amino acids it is shown that α-amino-hydroxamic acids 8 and 9 rearrange base-catalyzed to N-(α-aminoacyloxy)arylamines 10 and 11 which react with bionucleophiles such as deoxyguanosine (dG) (12), guanosine (G) (13) and 5′-guanosinemonophosphate (5′-GMP) (14) to form adducts. We describe the regioselective formation of the C-8 adducts of 4-chloroaniline (15), aniline (16), 4-methylaniline (17), and 4-methoxyaniline (18), respectively, [“N-(deoxyguanosine-8-yl)anilines”], and also of N-(guanosine-8-yl)-4-methylaniline (21) and 8-(4-methylanilino)-5′-guanosinemonophosphate (22). Similar reactions of the N-(acetoxy)arylamines 20, which are very likely to be “ultimate” carcinogens of aromatic amines, lead to the same C-8 adducts 15-18, 21, and 22 in comparable yields. These in vitro reactions thus show that the N-(α-aminoacyloxy)arylamines 10 and 11 react like the N-(acetoxy)anilines 20 as “ultimate” carcinogens. Therefore, the activation of aromatic hydroxylamines by O-α-aminoacylation is of similar quality as by O-acetylation.
    Additional Material: 3 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1707-1713 
    ISSN: 0009-2940
    Keywords: Conformational analysis ; Calculations, minimal-potential-energy ; Carcinogen adducts, borderline ; Nucleoside and nucleotide adducts of 4-methylaniline ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformations of the C-8-nucleobase adducts of the borderline carcinogen 4-methylaniline (p-toluidine) N-(deoxyguanosine-8-yl)-4-methylaniline (10), N-(guanosine-8-yl)-4-methylaniline (11), and 8-(4-methylanilino)-5′-guanosinemonophosphate (12) have been investigated by 1H-, 13C-NMR spectroscopy and “minimal-potential-energy” calculations. As far as the glycosidic bond is concerned, the 1H- and 13C-NMR data show in agreement with the calculations that the nucleoside adducts 10, 11 exist preferentially in the anti conformation while the 5′-phosphorylated nucleotide adduct 12 exists in the syn conformation. Different conformations are also observed around the backbone C-4′ - C-5′ bond. While the nucleoside adducts 10, 11 show a strong preference for the gauche-gauche conformation (ca. 90%), nucleotide adduct 12 exists mainly in the gauche-trans/trans-gauche conformation (ca. 70%). All adducts show a preference for the C-2′-endo conformation of the (deoxy)ribose puckering. A comparison of the conformational data of monocyclic arylamine adducts 10, 11, and 12 with the conformations of DNA- or oligonucleotide-bonded 2-[(deoxyguanosine-8-yl)amino]fluorene (6) shows, that the conformational situations in the case of the borderline carcinogen p-toluidine are similar to that of the strong hepatocarcinogen 2-aminofluoren (4b). The reasons for the different cancer-inducing potentials of borderline carcinogens like p-toluidine and strong carcinogens like 2-aminofluorene thus seems not to be connected with the conformational changes of the DNA double helix caused by adduct formation but rather with the in vivo metabolization to give the ultimate carcinogen.
    Additional Material: 6 Ill.
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