Beitrag zur absoluten Konfiguration der Spermin-Alkaloide O-Methylorantin und Aphelandrin. 175. Mitteilung über organische Naturstoffe

✍ Scribed by Peter Dätwyler; Herbert Bosshardt; Manfred Hesse; Siegfried Johne

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: German
• Weight: 824 KB
• Volume: 62
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19790620823

✦ Synopsis

Contribution to the Absolute Configuration of the Spermine Alkaloids O‐Methylorantine and Aphelandrine

The absolute configuration of the spermine alkaloid O‐methylorantine (1) isolated from Chaenorhinum minus (L.) WILLK. ET LGE. and Ch. villosum (L.) WILLK. ET LGE. was determined. Besides the difference in the substitution at C(31) (OCH~3~ versus OH) the constitution of 1 and aphelandrine (2) [6] is the same. This was established by spectroscopic evidence, by isomerization reactions of 2, orantine (4) and their derivatives (Scheme 2), and by degradation reactions of 1 and 4, respectively. The methyl ether 1 of orantine (4), the latter prepared by base catalyzed isomerization from aphelandrine (2), is in all respects identical with the natural O‐methylorantine (1). Orantine (4) is identical (UV., CD., ^1^H‐NMR. and TLC. evidence) with ephedradine A, recently isolated by Hikino et al. [8], who determined the absolute configuration of ephedradine A by X‐ray analysis. The absolute configuration of aphelandrine (2) was related to the one of 4 by chemical degradation.