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Titolo:
Oligonucleosides with a nucleobase-including backbone part 4 - A convergent synthesis of ethynediyl-linked adenosine tetramers
Autore:
Gunji, H; Vasella, A;
Indirizzi:
ETH Zentrum, Organ Chem Lab, CH-8092 Zurich, Switzerland ETH Zentrum Zurich Switzerland CH-8092 Lab, CH-8092 Zurich, Switzerland
Titolo Testata:
HELVETICA CHIMICA ACTA
fascicolo: 12, volume: 83, anno: 2000,
pagine: 3229 - 3245
SICI:
0018-019X(2000)83:12<3229:OWANBP>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
PURINE NUCLEOSIDES; CONFORMATION; NUCLEOTIDES; ANALOGS; DEPROTECTION; AGONISTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Vasella, A ETH Zentrum, Organ Chem Lab, Univ Str 16, CH-8092 Zurich, Switzerland ETH Zentrum Univ Str 16 Zurich Switzerland CH-8092 Switzerland
Citazione:
H. Gunji e A. Vasella, "Oligonucleosides with a nucleobase-including backbone part 4 - A convergent synthesis of ethynediyl-linked adenosine tetramers", HELV CHIM A, 83(12), 2000, pp. 3229-3245

Abstract

Deprotection of the tetramer 24, obtained by coupling the iodinated dimer 18 with the alkyne 23 gave the 8',5-ethynediyl-linked adenosine-derived tetramer 27 (Scheme 3). As direct iodination of C(5')-ethynylated adenosine derivatives failed, we prepared 18 via the 8-amino derivative 17 that was available by coupling the imine 15 with the iodide 7; 15, in its turn, was obtained from the 8-chloro derivative 12 via the 4-methoxybenzylamine 14 (Scheme 2). This method for the introduction of the S-iodo substituent was worked out with the N-benzoyladenosine 1 that was transformed into the azide 2 by lithiation and treatment with tosyl azide (Scheme I). Reduction of 2 led to the amine 3 that was transformed into 7 I,3-Dipolar cycloaddition of 3 and (trimethylsilyl)acetylene gave 6. The 8-substituted derivatives 4a-d were prepared similarly to 2, but could not be transformed into 7 The known chloride 8 was transformed into the iodide 11 via the amines 9 and 10. The amines 3, 10, and 16 form more or less completely persistent intramolecular C(8)N-H . . . O(5') H-bonds, while the dimeric amine 17 forms a ca. 50% persistent H-bond. There is no UV evidence for a base-base interaction in the protected and deprotected dimers and tetramers.

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Documento generato il 29/11/20 alle ore 23:59:14