Reaction of sulfonamide protected 5-vinylimidazole with 4-phenyl-1,2,4-triazoline-3,5-dione in methanol gave the Diels-Alder adduct 8 in 85% yield. Deprotection of the resulting N-phenyltriazole was efficiently accomplished by ring opening with hydrazine followed by heating in DMSO. The completely deprotected and aromatized purine analogue 1 was obtained directly from this one-pot reaction in 48% yield
描述了通过杂Diels-Alder反应制备3-脱氮-6-氮杂
嘌呤的一般方法。磺酰胺保护的5-
乙烯基咪唑与
4-苯基-1,2,4-三唑啉-3,5-二酮在
甲醇中的反应得到Diels-Alder加合物8,产率为85%。通过用
肼开环,然后在
DMSO中加热,有效地完成了所得N-苯基三唑的脱保护。直接从该一锅反应以48%的产率直接获得完全脱保护和芳香化的
嘌呤类似物1。