Synthesis of a thymidine building block for the preparation of novel conformationally restricted oligonucleotides
| Autor: | Tomasino, Tonino. |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1997 |
| Předmět: | |
| Druh dokumentu: | Electronic Thesis or Dissertation |
| Popis: | The synthesis of nucleosides (28a) and (28b) is described. The best procedure consisted of a five step synthesis from 5-methyluridine. Simultaneous protection of the 3'- and 5' -hydroxyl groups of 5-methyluridine with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane-1,3-diyl gave nucleoside (11). Base protection of nucleoside (11 ) with (trimethylsilyl)ethoxymethyl chloride provided product ( 24). It was transformed to its allyl ether (23) by reaction with allyl bromide and silver (11) oxide. Oxidation of ( 23) with N-methylmorpholine N-oxide and osmium tetroxide, followed by sodium metaperiodate afforded aldehyde (27). Desilylation of aldehyde (27) gave the desired nucleosides (28a) and (28b). 1H-NMR analysis of the diacetylated forms of the nucleosides indicated that both acetates at the newly formed anomeric center were in an axial conformation, and that structures and conformations (28a) and (28b) are a good representation for the two isomeric diols. Dimerization of nucleosides (28a) and (28b) are to be explored. Please refer to dissertation for diagrams. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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