Journal of heterocyclic chemistry

Ring closure reactions of azidouracils to oxazolo??and isoxazolopyrimidines

D Van Tinh, W Stadlbauer

文献索引：Van Tinh, Dang; Stadlbauer, Wolfgang Journal of Heterocyclic Chemistry, 1996 , vol. 33, # 4 p. 1025 - 1030

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被引用次数: 16

摘要

Abstract Thermolysis of 6-azidouracils 1 in the presence of polyphosphoric acid leads either to oxazolo [5, 4-d] pyrimidine-5, 7-diones 5 (by reaction with benzoic acid 2a) or to isoxazolo [3, 4-d] pyrimidine-4, 6-diones 7 (by reaction with aliphatic carboxylic acids 2b, c). 5- Benzoylpyrimidinetriones 12 could be shown to cyclize to isoxazolo [5, 4-d] pyrimidine-4, 6- diones 15 by chlorination with phosphorus pentachloride and subsequent reaction with ...