Reactions of ring-expanded xanthines containing the imidazo[4,5-<i>e</i>][1,4]diazepine ring system
作者:Anila Bhan、Ramachandra S. Hosmane
DOI:10.1002/jhet.5570300544
日期:1993.10
corresponding amino derivative 25, followed by ring-closure with sodium meth-oxide/methanol, yielded three products, a 5:6-fused system 26 and two 5:7 fused systems 27 and 28. The structures of 26 and 27 were confirmed by single-crystal X-ray diffraction analyses. A tentative reaction pathway for the formation of all three products has been proposed. Hydrolysis of 27 with aqueous hydrochloric acid resulted in
4,5,7,8-四氢-6 H-咪唑并[4,5- e ] [1,4]二氮杂-5,8-二酮在2-位进行溴化,在3-,4位有或没有取代基-或7位,使用溴,N-溴琥珀酰亚胺或乙酰基次螨。如在7中那样,用酯官能度活化6位并没有改变溴化位点。环打开前体的碱催化的溴化,二乙基2- [ Ñ - (1-苄基-5-硝基咪唑-4-碳基)氨基]丙二酸二乙酯(5),无论是在引入的烷氧基官能度导致高于氨基丙二酸酯侧链,产生17当用醇淬灭反应时,或在侧链降解中,当用水淬灭反应时,产生1-苄基-5-硝基咪唑-4-羧酰胺(19)。17和19两者都是通过5 经由溴中间体15的氧化溴化而形成的。通过5的碱催化甲基化获得了后者的间接证据,得到2-甲基-2- [ N-(1-(1-苄基-5-硝基酰亚胺-偶氮基-4-羰基)氨基]丙二酸二乙酯(21)。用N-溴代琥珀酰亚胺对5进行碱催化的溴化反应生成了两种产物二聚体24a含有取代的2,2