Reinvestigation of the Branimycin Stereochemistry at Position 17‑C

A conformational study of branimycin was performed using single-crystal X-ray crystallography to characterize the solid-state form, while a combination of NMR spectroscopy and molecular modeling was employed to gain information about the solution structure. Comparison of the crystal structure with its solution counterpart showed no significant differences in conformation, confirming the relative rigidity of the tricyclic system. However, these experiments revealed that the formerly proposed stereochemistry of branimycin at 17-C should be revised.本研究采用单晶X射线衍射（single-crystal X-ray crystallography）开展布兰霉素（branimycin）的构象研究，以表征其固态晶型；同时结合核磁共振波谱（NMR spectroscopy）与分子建模技术，获取其溶液结构相关信息。将晶体结构与对应的溶液结构进行对比后发现，二者构象无显著差异，这证实了该三环体系具有相对刚性。但本实验同时表明，此前提出的布兰霉素17位碳（17-C）的立体化学构型需要予以修正。