Steric and stereochemical effects on the free-radical bromination of tetracyclic and hexacyclic fragments of the MDR inhibitor N-acetylardeemin
作者:Esmeralda Caballero、Carmen Avendaño、J.Carlos Menéndez
DOI:10.1016/s0040-4020(99)00886-8
日期:1999.12
derivatives. Compounds with an increased steric hindrance at 11a afforded B-C ring aromatized derivatives. Hexacyclic derivatives of the, 7,9a,10,14b,15,15a-hexahydroindolo[3″,2″−4′,5′]pyrrolo[2′,1′−3,4]-pyrazino[2,1-b]quinazoline-5,8-dione system showed a behaviour similar to the ‘non-hindered’ tetracycles, leading to unsaturated analogues of the natural MDR inhibitor N-acetylardeemin. Unsaturated ardeemin
几种四环3,5a,6,10b,11,11a-hexahydro-2 H -pyrazino [2',1'-5,1] pyrrolo [2,3 - b ] indole-1,4- diones的溴化研究了自由基的条件。与相关吡咯并[2,3- b ]吲哚衍生物的文献数据相反,该反应通常发生在11a位而不是苄基10b位,然后消除,得到11,11a不饱和衍生物。在11a处位阻增加的化合物可提供B - C环芳构化衍生物。7,7a,10,14b,15,15a-hexahydroindolo [3“,2” -4',5'] pyrrolo [2',1'-3,4] -pyrazino [2,1-]的六环衍生物b] quinazoline-5,8-dione系统显示出与“无阻碍”四环相似的行为,从而导致天然MDR抑制剂N-乙酰乙二胺的不饱和类似物。还通过溴化四环系统的2-(邻叠氮苯甲酰基)衍生物,然后进行氮杂