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  • 1
    Electronic Resource
    Electronic Resource
    Synthese von 2′-Desoxyribofuranosiden des 7H-Pyrrolo[2,3-d]-pyrimidins: Einfluß des C-2-Substituenten auf die Fluoreszenz (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1719-1730 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 2′-Deoxyribofuranosides of 7H-Pyrrolo[2,3-d]pyrimidine: Influence of the C-2 Substituents on the Fluorescence7-Deaza-2′-deoxynebularine (2a), its 2-methylthio (2b) and 2-amino derivative (2c) have been synthesized via phase-transfer glycosylation of the nucleobases 3a, 3b, and 3c, respectively, with the 2-deoxyhalogenose 6. Glycosylation of 3a leads to the formation of a 3:1 mixture of the anomers 7a and 8a in 48-% total yield, the corresponding reaction of 3b or 3c gives mainly the β anomers in increased yield. Cleavage of the protecting groups yields 2a-c or the anomers 8a and 8c. The 2-methylthio group, as well as the 2-amino group increase the fluorescence of the parent nucleoside 2a.
    Notes: 7-Desaza-2′-desoxynebularin (2a), sein 2-Methylthio- (2b) und sein 2-Aminoderivat (2c) wurden durch Phasentransferglycosylierung der Aglycone 3a, 3b und 3c mit der Desoxyhalogenose 6 dargestellt. Die Glycosylierung von 3a führt in 48proz. Ausbeute zum 3:1-Anomerengemisch der toluoylierten Nucleoside 7a und 8a; die entsprechende Reaktion von 3b und 3c ergibt bei erhöhter Ausbeute hauptsächlich die β-Anomeren. Abspaltung der Schutzgruppen liefert 2a-c bzw. die Anomeren 8a und 8c. Sowohl die 2-Methylthiogruppe als auch der 2-Aminosubstituent verstärken die Fluoreszenz der Stammverbindung 2a.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419841012
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  • 2
    Electronic Resource
    Electronic Resource
    2-Amino-2′-desoxytubercidin und verwandte Pyrrolo[2,3-d]pyrimidinyl-2′-desoxyribofuranoside (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 15-19 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2-Amino-2′-deoxytubercidin and Related Pyrrolo[2,3-d]pyrimidinyl 2′-DeoxyribofuranosidesPhase-transfer glycosylation of 2-amino-4-chloro-7H-pyrrolo-[2,3-d]pyrimidine (4a) with 1-chloro-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranose (7) yields in a regio- and diastereoselective reaction the crystalline condensation product 5a. Nucleophilic displacement of the 4-chloro substituent of 5a or the unprotected nucleoside 2b opens a route to 2-amino-2′-deoxytubercidin (1) or the thionucleoside 3a. The anomers 8 and 9 of 2-deoxy-1,3,5-triO-(p-toluoyl)-D-erythro-pentofuranose were isolated from the glycosylation reaction carried out in the absence of the nucleobase.
    Notes: Phasentransferglycosylierung von 2-Amino-4-chlor-7H-pyrrolo-[2,3-d]pyrimidin (4a) mit 1-Chlor-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranose (7) führt regio- und diastereoselektiv zum kristallinen Verknüpfungsprodukt 5a. Dessen 4-Halogensubstituent oder der des ungeschützten Nucleosids 2b ist nucleophil substituierbar, wodurch 2-Amino-2′-desoxytubercidin (1) und das Thionucleosid 3a zugänglich werden. In Abwesenheit der Nucleobase konnten aus dem Glycosylierungsansatz die anomeren 2-Desoxy-1,3,5-tri-O-(p-toluoyl)-D-erythro-pentofuranosen 8 und 9 isoliert werden.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870104
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  • 3
    Electronic Resource
    Electronic Resource
    ara-7-Desazanebularin - Synthese eines fluoreszierenden Pyrrolo[2,3-d]pyrimidin-Nucleosids durch Phasentransferglycosylierung (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1576-1587 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: are-7-Deazanebularine - Synthesis of a Fluorescent Pyrrolo[2,3-d]pyrimidine Nucleoside by Phase-Transfer Glycosylationara-7-Deazanebularine (2b) and its 6-methylthio derivative 2a have been synthesized via phase-transfer glycosylation of 4-methylthio-7H-pyrrolo[2,3-d]pyrimidine (4a) with 1-bromo-2,3,5-tri-O-benzyl-D-arabinofuranose (7). Omitting the halogenose and carrying out the reaction of 4a or 4b in dichloromethane leads to the methylene-bridged chromophores 6a and 6b, respectively. In contrast to pyrrolo[2,3-d]pyrimidines with substituents in position 2 and 4 compound 4a is glycosylated at N-7 and N-1. The formation of anomers and isomers is influenced by the phase-transfer catalyst. The N-1-glycosylated 10 is sensitive against hydrolysis at the N-glycosylic bond which is not found for the N-7 isomer 8a. Debenzylation of the methylthio nucleosides 8a or 9a is accomplished using boron trichloride. Raney nickel catalyst removes the sulfur yielding the title compound 2b which exhibits strong fluorescence.
    Notes: ara-7-Desazanebularin (2b) und sein 6-Methylthio-Derivat 2a wurden mittels Phasentransferglycosylierung von 4-Methylthio-7H-pyrrolo[2,3-d]pyrimidin (4a) mit 1-Brom-2,3,5-tri-O-benzyl-D-arabinofuranose (7) dargestellt. In Abwesenheit der Halogenose entstehen aus 4a oder 4b in Dichlormethan die N-7-methylenverbrückten Bis-Chromophore 6a bzw. 6b. Im Gegensatz zu 2,4-disubstituierten Pyrrolo[2,3,-d]pyrimidinen wird 4a nicht nur an N-7 sondern auch an N-1 glycosyliert. Anomeren- wie Isomerenanteil lassen sich durch den Phasentransferkatalysator beeinflussen. Die N-1-glycosylierte Verbindung 10 ist im Vergleich zum N-7-Isomer 8a an der N-glycosylischen Bindung hydrolyselabil. Bortrichlorid debenzyliert 8a bzw. 9a zu den anomeren Methylthionucleosiden 2a und 9b. Durch Raney-Nickel-Desulfurierung wird die Titelverbindung 2b erhalten, die intensiv fluoresziert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319830913
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  • 4
    Electronic Resource
    Electronic Resource
    Facile Synthesis of 2′-Deoxyribofuranosides of Allopurinol and 4-Amino-1H-pyrazolo[3,4-d]pyrimidine via Phase-Transfer Glycosylation (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 563-570 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phase-transfer glycosylation of 4-methoxy-1H-pyrazolo[3,4-d]pyrimidine with the 2-deoxyribofuranosyl chloride 9 formed the N(1)-β-nucleoside 10a as main product (39%). As by-products the α-D-anomer 11a (7%) and the N(2)-isomer 12a (18%) were isolated. Assignment of these isomers was made on the basis of their 1H- and 13C-NMR spectra. Removal of the sugar-protecting groups yielded the 4-methoxy-nucleosides 10b, 11b, and 12b, respectively. Nucleophilic displacement of the 4-MeO-group gave the 2-deoxyribofuranosides 1-4 of allopurinol and 4-amino-1H-pyrazolo[3,4-d]pyrimidine.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680305
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis of 2′-Deoxyribofuranosides of 8-Aza-7-deazaguanine and Related Pyrazolo[3,4-d]pyrimidines (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1602-1613 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The N(1)- and N(2)-(2′-deoxyribofuranosides) 1 and 2, respectively, of 8-aza-7-deazaguanine were prepared via phase-transfer glycosylation in the presence or absence of Bu4NHSO4 as catalyst of 6-amino-4-methoxy-lH-pyrazolo[3,4-d]pyrimidine (7c) with 2-deoxy-3,5-di-O-(p-toluoyl)-α-D-erythro-pentofuranosyl chloride (10). On a similar route, but without catalyst and employing THF as organic phase, the 6-amino-4-chloronucleosides 11b and 12b were synthesized from 7a and converted into the N(1)-and N(2)-substituted 4-thioxo analogues 17a and 18a, respectively. The ratio of N(1)- to N(2)-glycosylation was 2:1 for 7c and 1:1 for 7a, viz. depending on the nucleobase structure. The rate of the H+-catalyzed N-glycosyl hydrolysis was strongly decreased for the N(2)-(β-D-2′-deoxyribofuranosides) as compared to the N(1)-compounds. However, the N(1)-nucleoside 1, which is an isostere of 2′-deoxyguanosine, is sufficiently stable to be employed later in solid-phase oligonucleotide synthesis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690714
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