Mamanine

Mamanine A -oxide (55) Sophora chrysophylla Seem. (107) C15H22N2O3 Amorph. 

The crystal structures of lupanine (15) and its derivatives were investigated as free bases (54-56) as well as protonated forms (57-60). In all structures examined ring A was a half-chair. The conformation of ring C is a boat, and rings B and D have chair conformations. In other cases rings B, C, and D had chair conformations (54-57,59). Lupanine derivatives mamanine (16) and pohakuline (17), possible metabolites in the biosynthesis of sparteine, were studied by... 

Mamanine and pohakuline were isolated from Sophora chrysophylla (67). Pohakuline (17) is considered to be the tetrahydro derivative of mamanine (16). 

The structure of these alkaloids was established on the basis of UV, IR, NMR, and MS, and proved by X-ray analysis. Further detailed studies (707) carried out on Sophora chrysophylla resulted in the isolation of one more new alkaloid that appears to be mamanine A -oxide (55). (-f)-Mamanine (16) was obtained by photoreduction and is easily oxidized to 55 by m-chlorobenzoic acid. 

Once again the azaphenalene, Nuphar, and Lythraceae alkaloids are included in this Chapter. Perhaps the most notable achievement of the year is the synthesis of azaphenalenes of ladybird beetles by Ayer and co-workers.Amongst the new alkaloids, the novel pyridone quinoiizidine, mamanine (3) and its tetrahydro-derivative, pohakuline (5) are of special interest. ... 

Scheuer and co-workers showed that during the flowering period the bark of Sophora chrysophylla contains the alkaloids mamanine (3) and its... 

The conversion of lupanine into camoensidine may represent a biosynthetic pathway, and cleavage of the C-16 C-17 bond of a tetracyclic quinolizidine [cf. mamanine (3)] followed by carbon-carbon cyclization could lead to tetracyclic derivatives containing terminal piperidine rings. New alkaloids of this type have been obtained recently. Aloperine was first isolated from Sophora alopercuroides over forty years ago, and structure (12) has now been assigned to the alkaloid on the basis of spectral studies. Allylaloperine (13) is a constituent of the same species. Nitraramine (14) and 7V-hydroxynitraramine (15) from Nitraria schoberi are... 

The structures of (+)-mamanine (80) and (+)-13P-hydroxymamanine (24) correspond to oxidative products derived from the Nj-Cjo cleavage of (-)-anagyrine... 

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