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Islam, Rafiqul Department of Drug Discovery and Development, Division of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
Nagamatsu, Tomohisa Department of Drug Discovery and Development, Division of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University
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.
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