Synthesis of Chelocardin, Amidochelocardin, Premithramycinon and Chromocyclin

本项目的目的是建立对chelocardin(2)、carbamidochelocardin(3)、pretramycinon(5)和chromocyclin（6/7）的合成途径。这些天然产物的特点是有一个共同的主链，它与已建立的四环素的不同之处在于在C2上有一个甲基酮，在C4上有不同的构型。在前曲霉素(5)和色环蛋白（6/7）的情况下，在位置4有一个醇部分而不是胺。所有天然产物都表现出不同的生物活性，因此是医学应用的宝贵起点。作为我们正在进行的使天然产物的生物活性合理化的计划的一部分，由于细微的结构变化，我们首先需要获得这些化合物，并有可能随意改变结构。所得化合物将用于靶标鉴定研究。然而，这个项目的目标是建立对上述天然产物的合成途径。

The aim of this project is to establish synthetic access to chelocardin (2), carbamidochelocardin (3), premithramycinon (5) and chromocyclin (6/7). These natural products are characterized by a common backbone, which differs from established tetracyclins only due to the presence of a methyl ketone at C2, and a different configuration at C4. In the case of premithramycinon (5) and chromocyclin (6/7) at position 4 there is an alcohol moiety instead of the amine. All natural products exhibit different biological activities and are therefore valuable starting points for medical applications. As part of our ongoing program to rationalize the biological activities of natural products due to subtle structural changes, we firstly need access to these compounds and the possibility to alter the structures at our will. The so-obtained compounds will afterwards being used for target identification studies. However, the goal of this project is to establish synthetic access to the above mentioned natural products.