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  • 1995-1999  (5)
  • Herpes simplex virus  (3)
  • Abrasive waterjet technology  (1)
  • Carduus nutans L.  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of 5-methylisocytidine derivatives (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 455-459 
    Details
    ISSN: 1434-4475
    Keywords: Herpes simplex virus ; Human immunodeficiency virus ; Isocytidines ; N2-alkyl-5-methyl ; Nucleosides ; convergent synthesis of ; 2-Thiouridine ; 5,S2-dimethyl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung N2-substituierte 5-Methylisocytidin-Derivate wurden ausgehend von S2-Methyl-2-thiothymidin entweder durch direkte Substitution der Methylthiogruppe durch eine Aminogruppe und anschließende Kondensation mit 1,2,3,5-tetra-O-Acetyl-β-D-ribofuranose zum acetylierten Nucleosid oder umgekehrt durch Synthese eines acetylierten 5,S2-Dimethyl-2-thiouridins und nachfolgende Behandlung mit dem entsprechenden Amin hergestellt.
    Notes: Summary N2-Substituted 5-methylisocytidine derivatives were synthesized from S2-methyl-2-thiothymine either by direct substitution of the methylthio group by an amino group and subsequent condensation with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose to give the acetylated nucleoside or by the opposite sequence first preparing an acetylated 5,S2-dimethyl-2-thiouridine followed by treatment with the appropriate amine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810888
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of 2-O-ethyl analogues of 3′-azido- and 3′-fluoro-2′,3′-dideoxyuridines and evaluation of their biological activity against HIV (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 811-817 
    Details
    ISSN: 1434-4475
    Keywords: Nucleosides ; convergent synthesis of ; Uridines, 2-O-ethyl ; Uridines, 2′,3′-dideoxy-3′-fluoro ; AZT analogues ; Human immunodeficiency virus ; Herpes simplex virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 2-O-Ethyluracil und 2-O-Ethylthymin wurden mit 1,1,1,3,3,3-Hexamethyldisilazan silyliert und in Gegenwart vonTMS-triflat mit 2,3-Dideoxy-3-fluoro-D-erythro-pentofuranosid, 3-Azido-2,3-dideoxy-D-erythro-pentofuranosid und 2,3-Dideoxy-3-phthalimido-β-D-erythro-pentofuranosederivaten zu den entsprechenden 2-O-Ethyl-Nucleosiden umgesetzt. Entfernung der Schutzgruppe mit gesättigter methanolischer Ammoniaklösung lieferte 2′,3′-Dideoxy-3′-fluor-2-O-ethyluridin; 3′-Azido-2′,3′-dideoxy-3-O-ethyl-uridin wurde durch Entschützung mit Tetrabutylammoniumfluorid in Tetrahydrofuran erhalten. 3′-Amino-2′,3′-dideoxy-3-O-ethyl-uridin konnte nur durch Behandeln des entsprechenden 3′-Azido-Nucleosids mit Triphenylphosphin in Pyridin hergestellt werden. 3′-Deoxy-2-O-ethyl-3′-fluor-thymidin (6b) zeigt geringe Aktivität gegenüber HIV-1.
    Notes: Summary 2-O-Ethyluracil and 2-O-ethylthymine were silylated with 1,1,1,3,3,3-hexamethyldisilazane and condensed in the presence ofTMS triflate with 2,3-dideoxy-3-fluoro-D-erythro-pentofuranoside, 3-azido-2,3-dideoxy-D-erythro-pentofuranoside, and 2,3-dideoxy-3-phthalimido-β-D-erythro-pentofuranose derivatives to give the corresponding 2-O-ethyl nucleosides. Deprotection with saturated methanolic ammonia afforded the 2′,3′-dideoxy-3′-fluoro-2-O-ethyluridines, whereas 3′-azido-2′,3′-dideoxy-3-O-ethyluridine was obtained by deprotection with tetrabutylammonium fluoride in tetrahydrofuran. 3′-Amino-2′,3′-dideoxy-3-O-ethyluridine could be obtained only by treatment of the corresponding 3′-azido nucleoside with triphenylphosphine in pyridine. 3′-Deoxy-2-O-ethyl-3′-fluorothymidine (6b) showed moderate activity against HIV-1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807175
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  • 3
    Electronic Resource
    Electronic Resource
    On the modelling of abrasive waterjet cutting (1996)
    Springer
    The international journal of advanced manufacturing technology 12 (1996), S. 255-265 
    Details
    ISSN: 1433-3015
    Keywords: Abrasive waterjet technology ; Erosion ; Machining processes ; Material cutting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Abrasive waterjet cutting operates by the impingement of a high-velocity abrasive-laden waterjet against the workpiece. The jet is formed by mixing abrasive particles with high-velocity water in mixing tubes and is forced through a tiny sapphire orifice. The accelerated jet exiting the nozzle travels at more than twice the speed of sound and cuts as it passes through the workpiece. This cutting process is being developed as a net-shape and near-net-shape machining process for cutting many metals and hard-to-machine materials. The narrow kerf produced by the stream results in neither delimitation nor stresses along the cutting path. This new technology offers significant advantages over traditional processes for its ability to cut through most sections of dense or hard materials without the need for secondary machining, to produce contours, and to be integrated into computer-controlled systems. The abrasive waterjet cutting process involves a large number of process and material parameters which are related to the waterjet, the abrasive particles, and workpiece material. Those parameters are expected to effect the material removal rates and the depth of cut. The purpose of the present work is to propose a model which is capable of predicting the maximum depth of cut for different types of materials using different process parameters. A comparison of the results of the proposed model and the models reported in the literature is introduced along with a discussion of the limitations of those models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239612
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis of 3′-deoxy-3′-fluoro and -3′-amino nucleosides from 2-methylthiopyrimidin-4(1H)-ones (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 979-988 
    Details
    ISSN: 1434-4475
    Keywords: Nucleosides, convergent synthesis of ; Nucleosides, 2′,3′-dideoxy-3′-fluoro ; Nucleosides, 2′,3′-dideoxy-3′-amino ; 2-Methylthiopyridin-4(1H)-one nucleosides ; Human immunodeficiency virus ; Herpes simplex virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Methyl-2,3-didesoxy-3-fluoro-5-O-(4-phenylbenzoyl)-β-D-erythro-pentofuranosid (3) und 1,5-di-O-Acetyl-2,3-didesoxy-3-phthalimido-β-D-erythro-pentofuranose (12) wurden in Gegenwart von Trimethylsilyltriflat als Katalysator mit den silylierten 2-Methylthiopyridin-4(1H)-onen2a, b zu den entsprechenden Nucleosiden5–6 und13 kondensiert. Bei diesen Reaktionen tritt als Nebenreaktion eine Öffnung der endocyclischen C-O — Bindung auf, sodaß auch die acyclischen Nucleoside4a, b gebildet werden. Die 3′-Fluoronucleoside wurden mit NH3/MeOH entschützt, die 3′-Phthalimidonucleoside mit Methylamin in Ethanol. Letztere Reaktion resultierte in eine gleichzeitigen Substitution der Pyrimidineinheit unter Austausch der Methylthiogruppe. Das 2-Methylthioanalogon zu 3′-Desoxy-3′-fluorthymidin zeigt mäßige Aktivität gegen HIV-1.
    Notes: Summary Methyl 2,3-dideoxy-3-fluoro-5-O-(4-phenylbenzoyl)-β-D-erythro-pentofuranoside (3) as well as 1,5-di-O-acetyl-2,3-dideoxy-3-phthalimodo-β-D-erythro-pentofuranose (12) were condensed with silylated 2-methylthiopyridin-4(1H)-ones2a, b in the presence of trimethylsilyl triflate as a catalyst to produce the corresponding nucleosides5, 6, 13. In these reactions, an endocyclic cleavage of C-O in3 took place; therefore, acyclic nucleosides4a, b were also formed. All 3′-fluoro nucleosides were deprotected with NH3/MeOH; the 3′-phthalimido nucleosides were deprotected with methylamine in ethanol. The latter method resulted in a concomitant substitution reaction in the pyrimidine moiety with replacement of the methylthio group. The 2-methylthio analogue of 3′-deoxy-3′-fluorothylmidine showed moderate activity against HIV-1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807039
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  • 5
    Electronic Resource
    Electronic Resource
    Use of a comparative approach to identify allelopathic potential and relationship between allelopathy bioassays and “competition” experiments for ten grassland and plant species (1996)
    Springer
    Journal of chemical ecology 22 (1996), S. 933-948 
    Details
    ISSN: 1573-1561
    Keywords: Allelopathy ; bioassay ; Carduus nutans L. ; comparative approach ; correlative evidence ; forage plant ; grassland ; phytometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Various allelopathy bioassays were used to evaluate the allelopathic potential of 10 grassland forage species against a common test (phytometer) species,Carduus nutans L. Aqueous extracts did not influenceC. nutans germination, although radicle elongation was often severely inhibited.C. nutans was strongly affected by shoot, but not root, leachates. Decomposing ground tissue had mixed effects, and often stimulated shoot production ofC. nutans. Calculation ofR 2 (coefficient of determination) values between these results, and the results of previous experiments investigating the effects of the same 10 species onC. nutans emergence and development in field plots and glasshouse competition experiments frequently revealed strong, statistically significant relationships. Our results therefore provide correlative evidence for the importance of allelopathy in field conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02029946
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