Bromotyrosine-derived metabolites from the spongeAiolochroia crassa
摘要:
A chemical investigation of secondary metabolites from the sponge Aiolochroia crassa has been performed and five bromotyrosine derivatives (1-5) were identified. Their structures have been assigned on the basis of spectroscopic analysis, of which araplysillin III (2) and hexadellin C (3) possess new structures. The absolute configurations of dibromotyrosine moieties of 2 were determined by HPLC analysis of derivatized constituent amino acids obtained from acid hydrolysis. The stereochemistry of the spirocyclohexadienylisoxazoline moiety of compounds 1-3 was deduced from spectroscopic comparison of the same moiety of aerothionin, of which the absolute configuration was previously assigned by X-ray and CD analysis. (C) 1999 Elsevier Science Ltd. All rights reserved.
Bromotyrosine-derived metabolites from the spongeAiolochroia crassa
作者:Hongfeng Gao、Michelle Kelly、Mark T. Hamann
DOI:10.1016/s0040-4020(99)00553-0
日期:1999.8
A chemical investigation of secondary metabolites from the sponge Aiolochroia crassa has been performed and five bromotyrosine derivatives (1-5) were identified. Their structures have been assigned on the basis of spectroscopic analysis, of which araplysillin III (2) and hexadellin C (3) possess new structures. The absolute configurations of dibromotyrosine moieties of 2 were determined by HPLC analysis of derivatized constituent amino acids obtained from acid hydrolysis. The stereochemistry of the spirocyclohexadienylisoxazoline moiety of compounds 1-3 was deduced from spectroscopic comparison of the same moiety of aerothionin, of which the absolute configuration was previously assigned by X-ray and CD analysis. (C) 1999 Elsevier Science Ltd. All rights reserved.
Synthesis of purpuroine A, nakirodin A and MDN-0104: The hidden puzzles and risk of error in their configurational assignments
作者:Wen-Ju Wu、Yikang Wu、Bo Liu
DOI:10.1016/j.tet.2017.01.029
日期:2017.3
The unusual (R) configuration previously assigned (with seemingly undoubted evidence) to purpuroin A and nakirodin A was disproved by synthesis. The optical rotation and NMR data for structure assigned for salt-free nakirodin A were made available for the first time. The difficulty and potential risk of error in configurationalassignments of diastereomers for remote stereocenters were exemplified
通过合成证明了先前分配给紫癜素A和那奇罗定A的异常(R)构型(貌似毫无疑问)。首次提供了分配给无盐那奇罗汀A的结构的旋光度和NMR数据。通过MDN-0104举例说明了远程立体中心的非对映异构体配置分配中的困难和潜在的错误风险。但是,比较精细的13 C NMR偏差仍可为此类问题提供解决方案。