在多磷酸存在下对6-azidouracils 1的热解会生成恶唑并[5,4- d ]嘧啶-5,7-二酮5(通过与苯甲酸2a反应)或异恶唑并[3,4- d ]嘧啶-4,6-二酮7(通过与脂族羧酸2b,c反应)。通过用五氯化磷氯化并随后与叠氮化钠反应,可以显示5-苯甲酰基嘧啶三酮12环化成异恶唑并[5,4 - d ]嘧啶-4,6-二酮15。
Ring closure reactions of azidouracils to oxazolo- and isoxazolopyrimidines
作者:Dang Van Tinh、Wolfgang Stadlbauer
DOI:10.1002/jhet.5570330404
日期:1996.7
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 phosphoruspentachloride and subsequent reaction with sodium azide.
在多磷酸存在下对6-azidouracils 1的热解会生成恶唑并[5,4- d ]嘧啶-5,7-二酮5(通过与苯甲酸2a反应)或异恶唑并[3,4- d ]嘧啶-4,6-二酮7(通过与脂族羧酸2b,c反应)。通过用五氯化磷氯化并随后与叠氮化钠反应,可以显示5-苯甲酰基嘧啶三酮12环化成异恶唑并[5,4 - d ]嘧啶-4,6-二酮15。
Various 9-substituted 8-phenyltheophyllines (III) were prepared in two steps starting from 5, 7-dimethyl-2-phenyloxazolo [5, 4-d] pyrimidine-4, 6 (5H, 7H)-dione (I). Thus, treatment of I with amines afforded 5-(N-substituted benzamidino)-1, 3-dimethylbarbituric acids (II). The reaction of II with thionyl chloride or phosphorus oxychloride gave III.