Heterocyclic Nucleosede Analogues by Cycloaddition Reactions of 1-Vinylthymine with 1,3-Depoles
作者:David R. Adams、Alan S. F. Boyd、R. Ferguson、David S. Grierson、Claude Monneret
DOI:10.1080/07328319808004220
日期:1998.6
1,3-Dipolar cycloaddition of 1-vinylthymine to azides, nitrile oxides, nitrones and nitronates has been investigated as a route to heterocyclic nucleoside analogues in which the nucleoside ribose moiety has been replaced by an alternative heterocycle. Reaction of 1-vinylthymine with highly reactive nitrile oxides affords 1(isoxazolin-5-yl)thymine products in excellent yield at room temperature. The less reactive nitrone dipoles undergo cycloaddition to 1-vinylthymine at elevated temperature to afford 1-(isoxazolidin-5-yl)thymine cycloadducts in good-to-moderate yields, but show a tendency to eliminate thymine from the cycloaddition products over long reaction times. Azide cycloadditions to 1-vinylthymine proceed only under forcing conditions to which the fragile triazoline products are unstable.
Synthesis of Dihydroisoxazole Nucleoside and Nucleotide Analogs
作者:Hung-Jang Gi、Yuejun Xiang、Raymond F. Schinazi、Kang Zhao
DOI:10.1021/jo961779r
日期:1997.1.1
The dihydroisoxazole nucleosides as well as their phosphonate derivatives were efficiently prepared via 1,3-dipolar cycloaddition reactions of nitrile oxides with corresponding vinyl nucleoside bases for antiviral studies.