Why are the terpenoid indole alkaloids of type I homochiral?

Beke, Gyula; Patthy-Lukáts, Ágnes; Podányi, Benjamin; Szabó, László

doi:10.1002/chir.1065

Cited by 6 publications

(2 citation statements)

References 13 publications

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“…[1][2][3][4] More than 2500 isolated representatives of them are formed mainly in three plant families Apocynaceae (APO), Loganiaceae (LOG) and Rubiaceae (RUB) from two building blocks secologanin 1 and tryptamine 2 through a single precursor strictosidine 3 (in this paper they are considered as indole alkaloids; however, sesqui-and dimer derivatives are temporarily disregarded). The narrow relatedness of the structures, the presence or absence of common structural elements, ring systems, functional groups, sesquimer and dimer alkaloids and stable centers of chirality 5,6 give important contributions to this work. And in addition, the chemotaxonomical data provide a strong support as well.…”

Section: 3mentioning

confidence: 99%

Molecular evolutionary lines in the formation of indole alkaloids derived from secologanin

Szabó¹

2008

Arkivoc

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Generation of the strictosidine → stemmadenine → ellipticine/olivacine and the strictosidine → vincadifformine→ rhazinilam/rhazinal molecular evolutionary lines indicated the multistep bioorganic interactions in the frame of indole alkaloids derived from secologanin. Narrow structural elements, detailed chemotaxonomic data and standard organic reaction mechanisms, together with computer search of the DNP databases contributed considerably to the knowledge of the chemical background of this important class of natural products and detected several longrange electronic connections between the nitrogen atoms in these molecules.

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Section: 3mentioning

confidence: 99%

Molecular evolutionary lines in the formation of indole alkaloids derived from secologanin

Szabó¹

2008

Arkivoc

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“…It was detailed elsewhere 25 that our stereochemical results might explain the high 3S stereoselectivity of the coupling reaction of secologanin and tryptamine in the presence of strictosidine synthase. As established in the present paper, bulky substituents of N-4 direct the chirality toward the formation of the 3S epimer in the spirooxindole system.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the Coupling Reaction of Tetraacetylsecologanin with Oxotryptamine and Its Derivative

et al. 2001

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The coupling reaction of tetraacetylsecologanin with 2,3-dihydro-2-oxotryptamine and its N(b)-benzyl derivative was investigated. With the benzylated amine, the reaction was stopped at the tetracyclic ester level, and with the unsubstituted amine it was immediately followed by lactamization. In both cases, the products were formed with high stereoselectivity at C-3, but as an epimeric pair of 7R and 7S in a ratio of 1:3. The bulky benzyl substituent at N-4 directed the stereoselectivity at C-3 in favor of the S configuration. In the nonbenzylated compounds, the reversible coupling reaction is probably nonstereoselective, but in lactamization the 3R epimer is sterically favored and faster and gives the final lactam in this configuration. The formation of the spiro compounds may serve as a model reaction in the interpretation of the stereoselectivity of the coupling reaction of secologanin with tryptamine in the presence of strictosidine synthase.

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Reaction mechanism and chemotaxonomy in the formation of the type I indole alkaloids derived from secologanin

Szabó

2006

J of Physical Organic Chem

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The history of biomolecules is written into the structure of their educts and products. The group of indole alkaloids derived from secologanin and tryptamine has more than 2000 individual compounds isolated mainly from the Rubiaceae, Loganiaceae, and Apocynaceae plant families and having strictosidine as a common precursor. To detect their history in its main lines, the compounds isolated from the same or closely related species were ordered as intermediates into reaction sequences according to the principles of basic organic reaction mechanisms. The analysis is restricted to the main lines of the monomeric alkaloids having one un-rearranged secologanin subunit (type I) closed to N-4 atom and one tryptamine subunit in intact or cleaved form. Deglucosylation of strictosidine opens the way for different types of cyclizations. Subsequent key bond-braking and bond-making reactions involve bond C-5-C-6 in the tryptamine subunit, bond C-15-C-16 in the secologanin subunit, and bond C-3-C-7 at the attachment of the two subunits, and indicate the crucial importance of a strong long-range through-bond interaction between the two nitrogen atoms. With a few principles it was possible to interpret such important biogenetic-type steps, as the formation of the akuammidan and akuammilan bridges, the transition from the vincosan into the strychnan and further to the aspidospermatan skeleton, the breaking and transformation of the side-chain of the triptamine subunit and the cleavage of the strategic bond C-15-C-16 toward the formation of the formation of type II and type III alkaloids.

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Why are the terpenoid indole alkaloids of type I homochiral?

Cited by 6 publications

References 13 publications

Molecular evolutionary lines in the formation of indole alkaloids derived from secologanin

Molecular evolutionary lines in the formation of indole alkaloids derived from secologanin

Investigation of the Coupling Reaction of Tetraacetylsecologanin with Oxotryptamine and Its Derivative

Reaction mechanism and chemotaxonomy in the formation of the type I indole alkaloids derived from secologanin

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