Aporphine-pavine dimers

Fourteen alkaloids were isolated from extracts of the whole plant of ThaUctrum fauriei Hayata, among which were seven alkaloids of novel structure including three aporphines (3-0-demethyloconovine, faurine, and O-methylfaurine), three aporphine-benzylisoquinoline dimers (fauridine, faurithaline, and 3-methoxyfaurithaline), and one aporphine-pavine dimer (fauripavine). Alkaloids of previously established structure that were isolated and identified included five aporphines (corydine, isocorydine, isooconovine, oconovine, and thalisopynine), and two morphinans (ocobotrine and pallidine). 

Two aporphine-pavine dimers, pennsylpavoline (171, R=H) and pennsylpavine (171, R=Me), together with their aporphine-benz-ylisoquinoline dimer precursors, pennsylvamine and pennsylvan-amine, have been isolated from Thalictrum polyganum (Shamma and Moniot, J.Amer.chem.Soc., 1974, 96, 3338). 

A continuing investigation of the alkaloids of Thalictrum polygamum Muhl. has resulted in the isolation of members of an interesting and novel isoquinoline group, the aporphine-pavine dimers. Pennsylpavine (59) and pennsylpavoline (60) are weakly basic phenolic alkaloids which are accompanied in the plant by the aporphine-benzylisoquinolines pennsylvanine (46) and pennsylvanamine (47). It therefore seems likely that (46) and (47) are biogenetic precursors for (59) and (60), respectively. ... 

A very useful complete listing of all proaporphine- and aporphine-benzyl-isoquinoline dimers, as well as aporphine-pavine dimers, together with their physical constants, has appeared. ... 

Comparison of the structures of pennsylvanine and pennsylvanamine, two dimers of the ( + )-thalicarpine series which co-occur with pennsylpavine and pennsylpavoline, furnishes prima facia evidence that aporphine-benzyliso-quinolines could act as biogenetic precursors to the aporphine-pavine dimers. 

The second dimeric base, (—)-pennsylpavoline (179), was shown to correspond to C-l-demethylpennsylpavine. Specifically, its NMR spectrum was devoid of the 8 3.71 singlet which represents the C-1 methoxyl absorption in (—)-pennsylpavine (178). Evaluation of CD spectra of these novel dimers and comparison with those of the aporphine (+)-A -methyllaurotetanine and the pavine (—)-platycerine led to the assignment of the absolute configurations as depicted in expressions 178 and 179. These dimers are probably derived biosynthetically from the aporphine-benzylisoquinoline dimers, (-)-pennsylvanine and (-)-pennsylvanamine, which were found in the same plant (7,173). 

H. Guinaudeau, M. Leboeuf, and A. Cave, J. Nat. Prod. 42, 133 (1979). Dimeric aporphine-benzylisoquinoline and aporphine-pavine alkaloids. Tabulates physical properties, sources, and references to synthesis of 28 alkaloids. 

Among the isoquinoline alkaloids, the aporphine-benzylisoquinolines had been considered a terminal stage of anabolic development in the biogenetic tree. The discovery of pennsylpavine and pennsylpavoline, two examples of a new group of dimeric alkaloids, the aporphine-pavines, has extended the biogenetic locus, since they are probably derived from aporphine-benzylisoquino-line dimers. 

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