The structures of two new alkaloids: chasmaconitine and chasmanthinine

A re-examination of the root of Aconitumchasmanthum Stapf has shown that it contains several alkaloids. Of these, besides indaconitine, the presence of which had been reported long ago, four new alkaloids have been isolated: base A (C26H43O6N), base B (C25H41O6N), chasmaconitine (C34H47O9N), and chasmanthinine (C36H49O9N). Chasmaconitine gives rise to bikhaconine on hydrolysis, and has been shown by conversion to delphinine to be N-ethyl-N-desmethyl-delphinine. Chasmanthinine is also hydrolyzable to bikhaconine. Whereas in chasmaconitine bikhaconine is esterified with acetic and benzoic acid, in chasmanthinine it is esterified with acetic and trans-cinnamic acid. The complete structures and absolute configurations of both bases are derived.Peer reviewed: YesNRC publication: Ye

The structure of homochasmanine

The structure of homochasmanine, a new alkaloid isolated from Aconitum chasmanthum Stapf, has been determined. Its empirical formula is C26H43O6N and the spectroscopic evidence shows that the base contains five methoxyl and one hydroxyl group. The presence of the hydroxyl group is confirmed by the formation of a monoacetyl derivative. That homochasmanine is 8-O-methylchasmanine has been shown by the synthesis of this substance from the previously known diacetylchasmanine.Peer reviewed: YesNRC publication: Ye

The oxidation of diterpenoid alkaloids

The highly oxygenated diterpenoid alkaloids possessing the same C\u2014N ring structure fall into two groups: group A containing the aconitine-like bases in which the C-6 methoxyl is \u3b1-oriented, and group B containing the lycoctonine-like bases in which the C-6 methoxyl is \u3b2-oriented. The alkaloids of both groups are oxidized rapidly at room temperature by neutral potassium permanganate. The oxidation dealkylates the amino group in the bases of group A giving rise to secondary bases while it converts the bases of group B to the corresponding lactams. The different course of the oxidation from one group to the other is due to the different orientation of the C-6 methoxyl, and can be used to determine the stereochemistry at C-6.Peer reviewed: YesNRC publication: Ye

Chasmanine and its structure

The alkaloid chasmanine, C25H41O6N, isolated from A. chasmanthum contains four methoxyl and two hydroxyl groups as well as an imino-ethyl. It undergoes the usual pyrolytic reaction and the unsaturated product, pyrochasmanine, C25H39O5N, gives rise to an acid-catalyzed allylic rearrangement product, isopyrochasmanine. Pyrochasmanine, on treatment with lithium aluminium hydride, is demethoxylated. ...Peer reviewed: YesNRC publication: Ye