Die Konstitution der Lobelia‐Alkaloide

Wieland, Heinrich; Dragendorff, Otto

doi:10.1002/jlac.19294730105

Cited by 24 publications

(6 citation statements)

References 4 publications

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“…1929 gelang Wieland und seiner Schülerin Irmgard Drishaus die Totalsynthese des Lobelins 98. Sie bestätigten damit die Konstitutionsformel, die durch Abbau des Alkaloids ermittelt worden war 99. Dieser wissenschaftlich verdienstvollen, technisch aber unbrauchbaren Synthese folgte im gleichen Jahr eine, die von Georg Scheuing und Ludwig Winterhalder bei Boehringer entwickelt worden war 100.…”

Section: Unter Der Nationalsozialistischen Diktatur (1933–1945)unclassified

Scope and Mechanistic Insights into the Use of Tetradecyl(trihexyl)phosphonium Bistriflimide: A Remarkably Selective Ionic Liquid Solvent for Substitution Reactions

McNulty

Nair

Cheekoori

et al. 2006

Chemistry A European J

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A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro over nitroso products and elimination side products. The structure-reactivity study indicates that these reactions proceed through a narrow spectrum of pathways ranging from straight S(N)2 to a preassociation pathway along a saddle point that approaches the S(N)1 limit. The barrier to the formation of dissociated carbocations is attributed to the structural features of this ionic liquid that favor intervention of the associated nucleophile over dissociation, also preventing cross over to E1 processes. The lack of any basic entity in the phosphonium bistriflimide ionic liquid appears to prevent any potential base-mediated elimination reactions, which makes this a highly selective medium for use in general substitution reactions.

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Section: Unter Der Nationalsozialistischen Diktatur (1933–1945)unclassified

Scope and Mechanistic Insights into the Use of Tetradecyl(trihexyl)phosphonium Bistriflimide: A Remarkably Selective Ionic Liquid Solvent for Substitution Reactions

McNulty

Nair

Cheekoori

et al. 2006

Chemistry A European J

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“…Several incorrect characterisations of lobeline were proposed before Wieland82 reported the correct chemical structure in 1929. This work was the starting point of extensive research into a better understanding of its complex pharmacological properties (vide infra).To date, five total syntheses of lobeline 1 have beenScheme 29.…”

mentioning

confidence: 97%

History, chemistry and biology of alkaloids from Lobelia inflata

Felpin¹,

Lebreton²

2004

Tetrahedron

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“…It invokes intermediacy of a 2-substituted piperidine (29), analogous in structure to the Decodon intermediate 27, and of a 2,6-disubstituted piperidine (30). The latter is analogous in structure (33) …”

Section: Alkaloids Withmentioning

confidence: 88%