Isolation, Structure Determination, and Synthesis of Allo-RA-V and Neo-RA-V, RA-Series Bicyclic Peptides from<i>Rubia cordifolia</i>L.
作者:Yukio Hitotsuyanagi、Masumi Odagiri、Saori Kato、Jun-ichi Kusano、Tomoyo Hasuda、Haruhiko Fukaya、Koichi Takeya
DOI:10.1002/chem.201103185
日期:2012.3.5
Two bicyclic hexapeptides, allo‐RA‐V (4) and neo‐RA‐V (5), and one cyclic hexapeptide, O‐seco‐RA‐V (6), were isolated from the roots of Rubia cordifolia L. Their gross structures were elucidated on the basis of spectroscopic analysis and X‐ray crystallography of compound 5. The absolute stereochemistry of compounds 4 and 5 were established by their total syntheses, and the absolute stereochemistry
从茜草的根中分离出两个双环六肽,allo-RA-V(4)和neo-RA-V(5),和一个环六肽,O- seco-RA-V(6) 。根据光谱分析和化合物5的X射线晶体学阐明了化合物的结构。化合物4和5的绝对立体化学是通过它们的总合成来确定的,化合物6的绝对立体化学是通过与脱氧布瓦丁的化学相关性确定的(3)。高活性RA-VII(1)与活性较低化合物的3D结构比较4和5表明,Tyr-5和/或Tyr-6苯环的取向在其生物活性中起着重要作用。肽4 – 6以及化合物3的分离以及它们结构的比较似乎表明,肽6可能是植物中双环肽3 – 5的常见前体。