Showing papers on "Indole alkaloid published in 1996"

Isolation of alkaloids from cultured hybrid cells of rauwolfia serpentina x rhazya stricta

Abstract: Two monoterpenoid indole alkaloids and four β-carbolines were isolated from a hydrid cell suspension culture generated from two Apocynaceous plants, Rauwolfia serpentina Benth. and Rhazya stricta Decaisne. This indicates that the function of alkoloid biosynthesis is retained after hybrid formation and that alkaloids not previously detected in the parental plants or cell cultures are formed.

Transgenic periwinkle tissues overproducing cytokinins do not accumulate enhanced levels of indole alkaloids

Abstract: Cytokinins play a critical role in several aspects of plant growth, metabolism and development We previously reported that adding cytokinins to the culture medium of a suspension-cultured cell line of periwinkle increased the accumulation of indole alkaloids, and our aim was to compare the effect of exogenously-applied cytokinins with that of elevated levels of endogenous cytokinins on indole alkaloid production We used an Agrobacterium tumefaciens strain yielding a plasmid with the isopentenyl transferase gene under control of its own promoter Co-culture of suspension cells with the bacteria caused a severe stress response leading to cell necrosis Therefore, we failed to transform this material but we succeeded in transforming periwinkle cotyledons We verified that callus cultures generated from the isopentenyl transferase-transgenic cotyledons accumulated high cytokinin concentrations Treating normal callus cultures (generated from untransformed cotyledons) with cytokinins enhanced their alkaloid production By contrast, the enhanced concentration of endogenous cytokinins in transgenic calli did not increase indole alkaloid production, and thus did not mimic the effect of exogenously-applied cytokinins Hypothesis to explain this discrepancy are discussed

synthesis of sempervirine, a pentacyclic anhydronium indole alkaloid

Abstract: Sempervirine (2,3,4,13-tetrahydro-1H-benz[g]indolo[2,3-a]quinolizin-6-ium,1) the pentacyclic anhydronium indole alkaloid ofGelsemium sempervirens Ait. f. (Loganiaceae), has been synthesized in three steps from hexahydroisochroman-3-one (6) and N-2-(3-indolyl)-ethylamine (tryptamine,7). The condensation product, N-2-(3-indolyl)-ethyl-2-(hydroxymethyl)-trans-hexahydrophenylacetamide (8) arising from6 and7 on double cyclization with phosphoryl chloride yielded the 3,4-dehydroyohimbane derivative9. Aromatization of rings C and D of compound9 with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in glacial acetic acid, followed by basification, generated sempervirine (1).

The First Total Synthesis of (‐)‐Mitragynine, an Analgesic Indole Alkaloid in Mitragyna speciosa.

Abstract: Starting from an optically pure alcohol, (R)-(3), which was prepared by enzymatic hydrolysis of the racemic acetate (2) or enantioselective reduction of the ketone derivative (4), the chiral total synthesis of mitragynine (1), a major corynanthe-type indole alkaloid having an analgesic effect in Mitragyna speciosa, was accomplished.

Total Syntheses of 10-Methoxydihydrocorynantheol and 10-Methoxycorynantheidol

Abstract: 10-Methoxydihydrocorynantheol and 10-methoxycorynantheidol were synthesized from 5-methoxytryptophol and 3-acetylpyridine. 13 C-NMR data of the prepared compounds and their synthetic intermediates are given.

Short, Stereospecific Total Synthesis of (.+‐.)‐Corynantheidine.

Abstract: A short, stereospecfic total synthesis of indole alkaloid (±)-corynantheidine 1 is described.