M. Zeches

Alkaloids from leaves and root bark ofErvatamia hirta

Abstract During chemical investigation of the leaves and root bark of Ervatamia hirta , 33 alkaloids were isolated. Seven are new: six are the ‘monomeric’ alkaloids ( E ) 16- epi -normacusine B , ( E ) 16- epi -affinisine, O -acetyl-16- epi -affinisine, affinisine- N (4)-oxide, dehydro-16- epi -affinisine, norfluorocurarine- N (4)-oxide, and the seventh is the bisindole 16-decarbomethoxyvoacamine-pseudoindoxyl. The known alkaloids are: ( E ) 16- epi -isositsirikine, β-yohimbine, yohimbine, 19,20-dehydro-β-yohimbine, β-yohimbine-pseudoindoxyl, isositsirikine, 19,20-dihydroisositsirikine, β-yohimbine-oxindole, normacusine B , affinisine, vobasine, dregamine, tabernaemontanine, norfluorocurarine, 12-hydroxynorfluorocurarine, apparicine, 3,14-dihydroellipticine, antirhine, voacristine, ibogaine, i☐ygaine, i☐ygaine-hydroxyindolenine, iboluteine, 4′,17,(17β)-dihydrotchibangensine, 16-decarbomethoxyvoacamine and 19,20-dihydro-16-decarbomethoxyvoacamine. Structural elucidation of the new alkaloids is based on spectral data and chemical correlations.

Further alkaloids from strychnos longicaudata and strychnos ngouniensis

Abstract Twenty four alkaloids have been isolated and identified from the root and stem barks of Strychnos longicaudata Gilg and Strychnos ngouniensis Pellegrin. Among these, 17 alkaloids are isolated for the first time; the novel bisindole series represented by longicaudatine includes now two other compounds: longicaudatines F and Y; besides ngouniensine, its epimer epingouniensine has been isolated along with two glucosyl-ngouniensines. Other new alkaloids include tubotaiwinal and several bases possessing the akuammicine skeleton.

Four cyclopeptide alkaloids from Zizyphus lotus

Abstract Cyclopeptide alkaloids were isolated from the root bark of Zizyphus lotus . The structures of two new compounds, lotusine A and lotusine D, were elu

Alkaloids from leaves and stem bark of Ervatamia polyneura

Abstract Twenty-three alkaloids were isolated from leaves and stem bark of Ervatamia polyneura, four of which are new: vobasenal, 16-epivobasenal, 3-oxo-19-epiheyneanine and 3-hydroxy-3,4-secocoronaridine. The other alkaloids are the known pericyclivine, vobasine, vobasine N-(4)-oxide, 16-epivobasine, vobasinol, dregamine, perivine, anhydrovobasindiol, apparicine, (+) tubotaiwine, voaphylline, 3, 14-dihydroellipticine, coronaridine, eglandine, eglandulosine, heyneanine, 19-epiheyneanine, voacangine and coronaridinehydroxyindolenine. Structural elucidation of the new alkaloids was based on spectral data.

Structure de l'échitamidine, d'un stéréoisomère et de deux régioisomères

Abstract The relative configuration of echitamidine is established by spectral and X-ray crystallographic techniques. Three other isomers are described and a structure is proposed for them.

Alcaloïdes des feuilles du Cinchona ledgeriana

Abstract Five monomeric and seven quasi-dimeric indole alkaloids were isolated from the leaves of Cinchona ledgeriana , five are known; the structures of two novel quasi-dimeric alkaloids have been elucidated by chemical correlation.

Benzophenanthridine and furoquinoline accumulation in cell suspension cultures of Fagara zanthoxyloides

Abstract In vitro cell culture of Fagara zanthoxyloides is reported for the first time. The cell suspension cultures produced fagaronine, but the production of this metabolite was lost after several subcultures, whereas furoquinoline accumulation remained high and constant.

Alkaloids from the leaves and stem bark of Ervatamia malaccensis

Abstract Chemical investigation of the leaves and stem bark of Ervatamia malaccensis afforded two novel alkaloids, N (1)-methoxymethuenine and N (1)-methoxy-19,20-dehydroervatamine together with the known alkaloids: 19,20-dehydroervatamine, 20-epiervatamine, methuenine, 16-epimethuenine, 6-oxomethuenine and dregamine. Structural elucidation of the new alkaloids was based on spectral data and on a chemical correlation.

The configuration of venoterpine

Abstract Venoterpine and cantleyine were chemically correlated and shown to have the same absolute configuration.

Alkaloids of melodinus guillauminii

Abstract Fourteen alkaloids were isolated from the stem bark and aerial parts of Melodinus guillauminii . They were 11-hydroxytabersonine, venalstonine, venalstonidine, 14,15-seco-3-oxokopsinal, 3-oxovenalstonine, 11-methoxy-Δ 14 – vincamenine, 3-oxo-hydroxykopsinine, 11-methoxy-Δ 14 -vincanol, kopsinine, 15-α-hydroxykopsinine, 11-methoxy- tabersonine, pleiocarpamine, 19-β-hydroxyvenalstonine and guillauminiine.