Cryptolepine, neocryptolepine, and isocryptolepine have remained popular synthetic targets ever since their isolation from the aqueous extracts of the West African climbing shrub Cryptolepis sanguinolenta. These natural alkaloids were found to contain significant antimalarial, antiproliferative and antimicrobial activities, making them ideal starting points for the development of novel drug candidates. As natural product synthesis is often plagued with step-heavy procedures and poor atom economy, the discovery of synthetic protocols addressing these concerns are sorely needed. In our laboratories, we have devoted our efforts into the development of regiodivergent synthesis whereby two of the indoloquinoline natural products, namely neocryptolepine and 11H-indolo[3,2-c]quinolines, could be assembled in only a few steps from a common and readily available starting material. Our synthetic endeavors to meet these goals include a cascade palladium-catalyzed Suzuki-Miyuara cross-coupling and intramolecular C−N bond formation and a photochemical nitrene insertion strategy. Furthermore, our methods also allowed for the construction of several diversely functionalized natural product derivatives which were subjected to biological evaluations.

中文翻译：

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吲哚喹啉类化合物的区域差异合成及其生物活性

自从从西非攀援灌木Cryptolepis sanguinolenta的水提取物中分离出来以来，Cryptolepine、neocryptolepine 和 isocryptolepine 一直是受欢迎的合成目标。这些天然生物碱被发现具有显着的抗疟、抗增殖和抗菌活性，使其成为开发新候选药物的理想起点。由于天然产物合成经常受到步骤繁重和原子经济性差的困扰，因此迫切需要发现解决这些问题的合成方案。在我们的实验室中，我们致力于区域差异合成的开发，其中两种吲哚喹啉天然产物，即新隐托平和 11 H-吲哚并[3,2- c ]喹啉，只需几步即可从常见的合成方法组装而成。和容易获得的起始材料。我们为实现这些目标所做的合成努力包括级联钯催化的 Suzuki-Miyuara 交叉偶联和分子内 CN 键的形成以及光化学氮宾插入策略。此外，我们的方法还允许构建几种不同功能化的天然产物衍生物，并对其进行生物学评估。