Melodinus scandens

The structures of the alkaloids of Melodinus scandens, viz., scandomeline, scandomelonine, and their C(19)-epimers have been reported previously (557). From the concentrated mother liquors of scandomeline, another bisindole scandomelidine (558) has been obtained, which was shown by the spectral data to be constituted from tabersonine- and aspidofractinine-type halves (352). Examination of the NMR spectral data and comparison with those of venalstonine (559), pachysiphine (547), and scandomelonine (560) led to structure 558 for scandomelidine, in which venalstonine is linked via C(10) to C(3 ) of pachysiphine, in the same manner as in scandomelonine (3 a-substitution). 

The antlmalarla drug quinine was synthesized by two different routes.tteloscandonine, an alkaloid from Melodinus scandens, has been assigned structure 11. Labeling experiments with Cinchona ledgerlana have helped to enumerate the middle and latter stages in the biosynthesis of the cinchona alkaloids (i.e.,... 

The occurrence of several of the Picralima bases in other genera has also been reported. Akuammine, for example, is present in Vinca rosea L. Cathar ant hits roseus G. Don (4), and it has also been extracted from the aerial parts of F. major L. (5-7). Akuammieine (IV) has been isolated from the roots of V. rosea (4, S) and 19,20-dihydroakuammicine from the leaves of Pleiocarpapycnantha (K. Schum.) Stapf., var. tubicina (Stapf.) Pichon (9). Akuammidine (V) occurs in the trunk bark of Melodinus australis (F. Mueller) Pierre (Apocyanaceac) (10), in Melodinus scandens Forst. (11), in the leaves of Vallesia dichotoma Ruiz et Pav. (12, 13), and has recently been shown to be one of the major alkaloids of Aspidosperma... 

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