Voachalotine

Upon hydrogenation (30) of voachalotine, the ethyl formed is in the same configuration as in ajmaline, which stands in contrast to the course of the(hydrogenation evinced by deoxysarpagine itself. The nature of the iV-methyl in voachalotine has been thoroughly studied by physical methods and compared with many model compounds (64). 

This could take place as depicted in L and/or LI to generate the 248 + R ion. The former route may be more favoured in the case of polyneuridine and voachalotine than in akuammidine. 

Sarpagine (75) and deoxysarpagine (76) have only fleeting effects on the blood pressure and the pressor amines. Voachalotine, like ajmaline, has some cardiotonic properties (77). Akuammidine is inactive in bird malaria (78). The alkaloids derived from Vinca species are probably... 

Oxidation of vincamajine (43) with CrOj in pyridine leads to voachalotinal (148) I3I, 170) (Scheme 15). 

Macroxine-A (159) is the first oxindole alkaloid with a C-17 to C-21 linkage through an oxygen atom in which the C-20-C-21 bond has been cleaved, resulting in a propyl side chain. Biogenetically, macroxine-A may arise from voachalotine oxindole, or one of its close analogs, by a series of transformations as depicted in Scheme 12. 

A,a-Methyl-16-epipericyclivine [16-De(hydroxymethyl)voachalotine] Alstonia undulata... 

Voachalotine Alstonia legouixiae Ervatamia yunnanensis Peschiera buchtieni Peschiera campestris Tabemaemontana fuchsiaefolia Voacanga chalotiana... 

Scheme 14. Transformation of vincamajine (145) to voachalotinal (63) and 17-hydroxy-6,17-O-dehydrovoachalotine (69). Reagents (i) CrOj/py (ii) DDQ/THF/H20.

For example, the chemical shifts presented for E-akuammidine (53) (242) are those of an unknown compound that definitely is not E-akuammidine. Several of the 13C NMR values given for pericyclivine (18) (105) need to be interchanged. As in the case of the H NMR spectra, Jokela and Lounas-maa (239) reexamined and corrected the 13C NMR spectral data of the five basic sarpagine alkaloids normacusine B (2), pericyclivine (18), E-akuammidine (53), polyneuridine (54), and voachalotine (64). The corrected data, confirmed by HETCOR measurements, are reproduced in Table IV. References for the 13C NMR spectral data of individual compounds, when available, are given in Table IV. 

The mixture of constituents [e.g., normacusine B (2), affinisine (8), Na-methylpericyclivine (41), voachalotine (64)] present in Peschiera van heur-ckii from the tropical rain forest in Bolivia is known for its alleged leishmani-cidal and bactericidal activity (37). Like many quaternary alkaloids, the major quaternary alkaloid from Strychnos angolensis, 11-methoxymacusine A (76), shows muscle-relaxant activity (187). The crude mixture of nine alkaloids present in Ervatamia yunnanensis is used in Chinese folk medicine for the treatment of hypertension (176). One of these alkaloids is a sarpagine derivative [voachalotine (64)]. 

In other extractions, vobasine has been isolated from the leaves of Peschlera echinata, voachalotine, vincamajine,... 

Voachalotine (49) (Scheme 14) undergoes " von Braun degradation to give an ether (50) of the taberpsychine type. Oxidation of this alkaloid with... 

Voachalotine also isolated from this somce. 

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