ID | 34214 |
FullText URL | |
Author |
Islam, Rafiqul
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Abstract | Several alkylating agents, for example alkyl halides and dimethyl sulfate, were employed in aprotic Solvents Under a variety of conditions for the alkylation of mono- and disubstituted 1H- or 3H-[1,2,3]triazolo[4,5-d]pyrimidine-5,7(4H,6H)-diones, which were prepared by cyclization of the appropriate 5,6-diaminouracils with nitrous acid. The alkylation on the triazole ring in the presence of anhydrous potassium carbonate took place simultaneously at the 1- and 2-positions, with alkylation at the 2-position taking priority. Similar alkylation on the pyrimidine ring with an equivalent alkylating reagent took place only at the 4-position. The alkylation of 3,6-disubstituted derivatives at room temperature led to 5-O-alkylation accompanied by 4-N-alkylation, but at high temperature only 4-N-alkylation took place. Reaction of 3,4,6-trisubstituted derivatives with excess alkylating agent at high temperature leads to the formation of 1,4,6-trisubstituted derivatives with elimination of the 3-substituent. |
Keywords | 8-azaxanthines
triazolopyrimidines
regioselectivity
alkylations
heterocycles
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Note | Published with permission from the copyright holder.
This is a author's copy,as published in Synthesis-Stuttgart , 2006 Issue.24 pp.4167-4179 Publisher URL: http://dx.doi.org/10.1055/s-2006-950337 Direct access to Thomson Web of Science record Copyright © 2008 by Georg Thieme Verlag Stuttgart |
Published Date | 2008-07-10
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Publication Title |
Synthesis-Stuttgart
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Issue | issue24
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Start Page | 4167
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End Page | 4179
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Content Type |
Journal Article
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language |
English
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Refereed |
True
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DOI | |
Web of Science KeyUT | |
Submission Path | organic_chemistry/10
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