The Castagnoli–Cushman reaction of 3,4-dihydroisoquinolines with glutaric anhydride, its oxygen and sulfur analogues was investigated as a one-step approach to the benzo[a]quinolizidine system and its heterocyclic analogs. An extension towards the pyrrolo[2,1-a]isoquinoline system was achieved with the use of succinic anhydride. The results are evidence of an unexplored method for the access of the aforementioned tricyclic annelated systems incorporating a bridgehead nitrogen atom. The structures and relative configurations of the new compounds were established by means of 1D and 2D NMR techniques. The reactions between 1-methyldihydroisoquinoline and glutaric, diglycolic and succinic anhydrides yielded unexpected isoquinoline derivatives containing an exocyclic double bond. The compounds prepared bear the potential to become building blocks for future synthetic bioactive molecules.

中文翻译：

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通过 Castagnoli-Cushman 方案一步制备三环稠合 1,2,3,4-四氢异喹啉系统。


研究了 3,4-二氢异喹啉与戊二酸酐及其氧和硫类似物的 Castagnoli-Cushman 反应，作为苯并[ a ]喹啉西啶系统及其杂环类似物的一步法。通过使用琥珀酸酐，实现了吡咯并[2,1- a ]异喹啉系统的扩展。该结果证明了一种尚未探索的方法，用于访问上述包含桥头氮原子的三环稠化系统。通过一维和二维核磁共振技术确定了新化合物的结构和相对构型。 1-甲基二氢异喹啉与戊二酸酐、二甘醇酸酐和琥珀酸酐之间的反应产生了意想不到的含有环外双键的异喹啉衍生物。制备的化合物有可能成为未来合成生物活性分子的基础材料。