Corynantheine-Heteroyohimbine-Yohimbine Group, and Related Oxindoles

2 Corynantheine-Heteroyohimbine-Yohimbine Group, and Related Oxindoles.— The chemotaxonomic significance of the pattern of 

In a search for new biosynthetic intermediates among the minor constituents of the leaves of Pauridiantha lyalli (Baker) Brem, Levesque a. have isolated two new glycosides, which prove to 

Strychnos decussate (Pappe) Gilg. is another plant which has been subjected to re-examination. Four new alkaloids have 

Sixteen alkaloids have been isolated from the leaves, stem bark, and root bark of Anartia meyeri tG. Don) Miers (sub-tribe Tabernaemontanineae), a shrub found in Guyana, which has not 

another Guyanese member of the sub-tribe Tabernaemontanineae, also appears to be a prolific source of indole alkaloids, and 

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C. Corynantheine-Heteroyohimbine-Yohimbine Group and Related Oxindoles... 

Monoterpenoid Alkaloids.—Corynantheine-Heteroyohimbine- Yohimbine Group, and Related Oxindoles. The leaves of Strychnos decussata (Pappe) Gil. contain a new glycosidic alkaloid for which the gross structure (78) has been proposed 52 so far, nothing is known about its stereochemistry. Nevertheless it seems distinctly possible that this alkaloid is a close biosynthetic relative of vallesiachotamine. 

Monoterpenoid Alkaloids.—Corynantheine-Heteroyohimbine-Yohimbine Group, and Related Oxindoles. The first recorded extraction of the leaves and twigs of Peschiera laeta Mart, has yielded geissoschizol, a base not previously found in the Peschiera genus. Antirhine and, to a lesser extent, its quaternary Nb-metho-derivative, occur in the bark of Strychnos camptoneura Gilg. et Busse and in Amsonia elliptica, which also contains tetrahydrosecamine, pleiocarpamine,... 

Corynantheine-Heteroyohimbine-Yohimbine Group, and Related Oxindoles. A comprehensive review " of the alkaloids of Uncaria species provides a valuable summary of the considerable number of investigations reported on the alkaloid content and the chemotaxonomy of UrKoria, and it also includes Ridsdale s revision of the genus, which has resulted in the recognition of 34 species-a considerable reduction and simplification when compared with the 120 recorded in the Kew Index. 

Monoterpenoid Alkaloids. — Corynantheine - Heteroyohimbine - Yohimbine Group, and Related Oxindoles. Details of the AT-ray crystal structure determination of borreline (92) have now been published,and the species from which it was isolated has been identified as Borreria capitata R. et P. A second alkaloid from this species, borrecapine (93), has a similar structure but, in place of the second methyl group in borreline, borrecapine contains an isobutenyl group which completes the monoterpenoid unit of the non-tryptamine part of the molecule. 

Monoterpenoid Alkaloids.— Yohimbine-Corynantheine-Heteroyohimbine and Related Oxindoles) Group. Holeinine ° from Bleekeria vitiensis ° (and Ochrosia sandwicensis) is isoreserpiline metho-salt the former source contains, inter alia, 10,11 -dimethoxyalstonine. ... 

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