SYNTHESIS OF ANTICANCER AGENTS

该授权申请描述了多种有效的抗肿瘤剂的建议的全合成， 天然来源的，即洛麦维他菌素A和B、cytoskyrin A、amphidinobenzene N和caribenobenzene I，以及 用于生物筛选的相关分子的数量。所提出的洛麦替星的全合成将 涉及高级α-卤代烯酮中间体的二聚化以产生C2-对称多环 框架.空间拥挤的中央核心的进一步加工将由 临时并入桥接环状系链。已经设计了两种替代的这种系绳，即 四氢噻吩和带有侧基酯基团的碳环，增加了整体的柔性， 战略一旦安装了所需的结构图案，这些桥中的任何一个都可以被氧化。 裂解以显示完成靶分子所必需的功能。对于cytoskyrin A， 提供靶分子的笼状框架的仿生级联过程已经被 实验证明。涉及蒽醌衍生物的酸催化二聚反应 随后是双烯醇化/双分子内迈克尔加成序列，仔细监测这一点， 级联反应不仅允许选择性地产生cytoskyrin A的中心核心，而且允许选择性地产生cytoskyrin A的中心核心。 许多其他结构相关的生物活性天然产物。这个级联过程将是 不仅适合生产这些天然产品本身，而且适合生产特定的 靶向类似物，其将被筛选抗肿瘤活性。两性霉素的合成方法 N和caribenetrine I具有统一的，高度收敛的策略，涉及顺序不对称 手性1，3-二羟基丙酮等价物的烷基化，以建立手性1，3-二羟基丙酮等价物的完整碳骨架。 靶分子，然后进行高度选择性的大环内酯化，以生成26元环， 每个案件。这项工作的重要性将具体体现在癌症化疗领域 研究，以及开发新的合成策略和技术，用于药物的一般用途 发现和发展过程。

This grant application describes the proposed total syntheses of a number of potent antitumor agents of natural origin, namely lomaiviticins A and B, cytoskyrin A, amphidinolide N and caribenolide I, as well as a number of related molecules for biological screening. The proposed total synthesis of the lomaiviticins would involve the dimerization of an advanced a-halo enone intermediate to generate the C2-symmetric polycyclic framework. Further elaboration of the sterically crowded central core would then be facilitated by the temporary incorporation of a bridging cyclic tether. Two alternative such tethers have been devised, namely a tetrahydrothiophene and a carbocycle bearing a pendant ester group, increasing the flexibility of the overall strategy. Once the required structural motifs are installed, either of these bridges could be oxidatively cleaved to reveal the necessary functionalities for completion of the target molecules. For cytoskyrin A, a biomimetic cascade process to furnish the cage-like framework of the target molecule has been experimentally demonstrated. Involving the acid-catalyzed dimerization of an anthraquinone derivative followed by a bis-enolization/ double intramolecular Michael addition sequence, careful monitoring of this cascade allows for the selective generation of the central core of not only cytoskyrin A, but also that of a number of other structurally related biologically active natural products. This cascade process would be amenable to the production of not only these natural products themselves, but also to that of specifically targeted analogs, which would be screened for antitumor activity. The proposed syntheses of amphidinolide N and caribenolide I feature a unified, highly convergent strategy involving the sequential asymmetric alkylation of a chiral 1,3-dihydroxyacetone equivalent to establish the complete carbon framework of the target molecules, followed by a highly selective macrolactonization to generate the 26-membered ring in each case. The significance of the proposed work will lie specifically in the area of cancer chemotherapy research, and in the development of new synthetic strategies and technologies for general use in the drug discovery and development process.