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  • 1
    ISSN: 1434-4475
    Keywords: Michael type addition ; L-Nucleosides ; 2′,3′,6′-Trideoxy-L-hexofuranose nucleosides ; 3′-(1,2,4-Triazol-1-yl) nucleosides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die quecksilberkatalysierte Hydrolyse von acetyliertemL-Rhamnal1 ergab die α,β-ungesättigten Aldehyde2. 1,2,3-Triazol wurde in Gegenwart von 1,8-Diazabicyclo[5.4.0]-7-undecen mittels einer Addition vom Michael-Typ an C-3 von2 gekoppelt und ergab dann nach Acetylierung am anomeren Zentrum eine anomere Mischung von 1,5-Di-O-acetyl-3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranose (3). Die Reaktion von3 mit silyliertem 2,4-Di-hydroxypyrimidinen4 in Gegenwart von Trimethylsilyltriflat in absolutem Ethanol ergab die entsprechenden Nucleoside7 und8.
    Notes: Summary Mercuric catalyzed hydrolysis of acetylatedL-rhamnal1 gave the α,β-unsaturated aldehyde2. 1,2,4-Triazole was coupled, in a Michael type addition reaction, to2 at C-3 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to give, after acetylation at the anomeric center, an anomeric mixture of 1,5-di-O-acetyl-3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranose (3). Reaction of3 with silylated 2,4-dihydroxypyrimidines4 in the presence of trimethylsilyl triflate as catalyst followed by deprotection with 33% methylamine in absolute ethanol afforded the corresponding nucleosides7 and8.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-4475
    Keywords: Keywords. Nucleosides ; convergent synthesis of; Nucleosides ; 3′-azido-2′-deoxy; Nucleosides ; 2′ ; 3′-didehydro; Nucleosides ; 3′ ; 4′-didehydro; 5-Alkoxymethyluracil nucleosides; Human immunodeficiency virus; Herpes simplex virus.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Reaktion von Methyl-5-tert-butyldiphenylsilyl-2,3-dideoxy-3-iodo-D-threo-pentofuranosid (3) mit den silylierten 5-Alkoxymethyluracilen 2a–c unter Verwendung von Trimethylsilyltrifluormethansulfonat als Katalysator ergab die α-Nucleoside 4a–c und die β-Nucleoside 5a–c. Die entsprechenden 3′,4′- und 4′,5′-Didehydronucleoside 6–9 wurden durch Behandeln der Jodnucleoside 4a–c oder 5a–c mit 10 Äquivalenten Natriummethoxid in siedendem Methanol über eine Eliminierungsreaktion hergestell. Die entschützten 3′-Azidonucleoside 10a–c und 11a–c vom AZT-Typ wurden ebenso wie die 4′,5′-Didehydronucleoside 7a–c und 9a–c durch Umsetzung von 4a–c und 5a–c mit Natriumazid und nachfolgender Behandlung mit Tetrabutylammoniumfluorid erhalten.
    Notes: Summary.  Reaction of methyl 5-tert-butyldiphenylsilyl-2,3-dideoxy-3-iodo-D-threo-pentofuranoside (3) with silylated 5-alkoxymethyluracils 2a–c using trimethylsilyl trifluoromethanesulfonate as a catalyst afforded the α nucleosides 4a–c and the β nucleosides 5a–c. The corresponding 3′,4′- and 4′,5′-didehydro nucleosides 6–9 were prepared in an elimination reaction by treating the iodo nucleosides 4a–c or 5a–c with 10 equivalents of sodium methoxide in methanol under reflux. The deprotected 3′-azido nucleosides 10a–c and 11a–c of the AZT type as well as the 4′,5′-didehydro nucleosides 7a–c and 9a–c were prepared by treating 4a–c and 5a–c, respectively, with sodium azide and subsequently with tetrabutylammonium fluoride.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 130 (1999), S. 1167-1173 
    ISSN: 1434-4475
    Keywords: Keywords. Triazenopyrazoles; Nucleosides ; convergent synthesis of; Nucleosides ; 1-(5-triazeno)pyrazole; Nucleosides ; 2-(5-triazeno)pyrazole; Human immunodeficiency virus; Herpes simplex virus.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Ethoxymethylenmalonitril und Bis(methlthio)methylenmalonitril wurden mit Hydrazinhydrat zu 5-Aminopyrazol-4-carbonitril (3a) und 5-Amino-3-methyltiopyrazol-4-carbonitril (3b) umgesetzt. Behandlung mit salpetriger Säure und Kupplung mit verschiedenen sekundären Aminen ergab die Triazenopyrazole 4a–j. 5-(3,3-Diethyl-1-triazeno)pyrazol-4-carbonitril (4c) wurde in seine beiden regioisomeren 2-Deoxyribonucleoside 5a,bübergeführt, welche anschließend mit H2O2/OH− zu den entsprechenden Carboxamiden 6a,b hydrolysiert wurden. Alle hergestellten Verbindungen wurden auf ihre biologische Aktivität gegenüber HIV-1 und Herpes simplex getestet. Nur 4c zeigte geringfügige Aktivität gegenüber HIV-1 (ED 50=32μM).
    Notes: Summary.  Ethoxymethylenemalononitrile and bis(methylthio)methylenemalononitrile were condensed with hydrazine hydrate to yield 5-aminopyrazole-4-carbonitrile (3a) and 5-amino-3-methylthiopyrazole-4-carbonitrile (3b), respectively. These compounds were treated with nitrous acid and coupled with different secondary amines to yield the triazenopyrazoles 4a–j. 5-(3,3-Diethyl-1-triazeno)pyrazole-4-carbonitrile (4c) was transferred into its two regioisomeric 2-deoxyribose nucleosides 5a,b which were subsequently hydrolyzed with H2O2/OH− to give the corresponding carboxamides 6a,b. All synthesized compounds were tested for biological activity against HIV-1 and herpes simplex virus, but only 4c showed moderate activity against HIV-1 with ED 50=32μM.
    Type of Medium: Electronic Resource
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