Abstract
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has been investigated as a route to heterocyclic nucleoside analogues in which the nucleoside ribose moiety has been replaced by an alternative heterocycle.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.
Original language | English |
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Pages (from-to) | 1053-1075 |
Number of pages | 23 |
Journal | Nucleosides and Nucleotides |
Volume | 17 |
Issue number | 6 |
Publication status | Published - 1998 |