Ipobscurines C and D: macrolactam-type indole alkaloids from the seeds of Ipomoea obscura |
| |
Authors: | Jenett-Siems Kristina Weigl Robert Kaloga Macki Schulz Jutta Eich Eckart |
| |
Affiliation: | Institut für Pharmazie (Pharmazeutische Biologie), Freie Universit?t Berlin, K?nigin-Luise-Str 2-4, D-14195 Berlin, Germany. |
| |
Abstract: | Separation of the methanolic seed extract of Ipomoea obscura afforded five indole alkaloids, three of them (ipobscurines B-D) being new natural products of a unique structural type characterized as serotonin hydroxycinnamic acid amide-type conjugates with a second phenylpropanoid moiety forming an ether with the 5-OH position of the indole nucleus. Due to an oxidative phenolic coupling between the two phenylpropanoid moieties of the supposed precursor ipobscurine B two 21-membered macrolactams with a phenol ether partial structure are formed: the trans-cis isomers ipobscurines C and D. Their structures were established on the basis of spectral data. Moreover, total synthesis of the racemic erythro- and threo-ipobscurine B 4',4"-dimethyl ethers and the comparison with the corresponding derivative of natural (-)-ipobscurine B proved an erythro configuration of the latter. |
| |
Keywords: | Ipomoea obscura Convolvulaceae Indole alkaloids Serotonin Hydroxycinnamic acid amide-type conjugates Ipobscurines Neolignans |
本文献已被 ScienceDirect PubMed 等数据库收录! |