3-Methylindole reacts with pyridines in the presence of NBS to give indol-2-yl-pyridinium salts which were converted into their ylides by an anion exchange resin in its hydroxide form. Indol-3- amine was subjected to a nucleophilic ring transformation with pyrylium salts which resulted in the formation of indol-3-yl-pyridinium salts, the 2,4,6-trimethylpyridinium derivative of which proved to be unstable. The 2,4,6-triphenylpyridinium derivate was deprotonated to the corresponding ylide. The isomeric indol-2-yl and indol-3-yl derivatives are cycloimmonium ylides which are members of the compound class of heterocyclic mesomeric betaines (MB). By contrast, the ylide of indol- 2-yl-pyrrolidinium is a cycloammonium ylide. It was prepared by reaction of 3-methylindole with pyrrolidine in the presence of NBS, followed by deprotonation.
Graphical Abstract

Syntheses and Characterization of N-(Indolyl)pyridinium Salts and of Their Ylides
© 1946 – 2014: Verlag der Zeitschrift für Naturforschung
Articles in the same Issue
- Chemistry of Iminium Salts, Imines, and Related Compounds
- Thiaminpyrophosphat – ein natürlich vorkommendes Iminium-Salz. Seine Bedeutung für die mikrobiellen Prozesse bei der Weinbereitung und die Aromabildung im Wein / Thiamine Diphosphate – A Natural Iminium Salt. Its Role in Microbiological Processes During Wine Preparation and on the Aroma of Wine
- Formation of Azolo[1,2,4]triazinium Salts by Reaction of Heterocyclicsubstituted 1-Azo-naphthalen-2-ols with Strong Acids
- Synthesis of Methyl 3-Azidothieno[2,3-b]pyridine-2-carboxylates and Application of the Huisgen Reaction
- Orthoamide und Iminiumsalze, LXXXVII [1]. Eine neue, einfache Synthese für 1,3-Dimethylthymin / Orthoamides and Iminium Salts LXXXVII [1]. A New and Facile Synthesis of 1,3-Dimethylthymine
- Orthoamide und Iminiumsalze, LXXXIV [1]. Die Synthese von starken Formylierungsmitteln im präparativen Großmaßstab: Tris(dichlormethyl)amin / Orthoamides and Iminiumsalts LXXXIV [1]. The Synthesis of Strong Formylating Reagents on a Large Preparative Scale: Tris(chloromethyl)amine
- Orthoamide und Iminiumsalze, LXXXV [1]. Die Synthese von starken Formylierungsmitteln im präparativen Großmaßstab: N,N,N',N'- Tetraformylhydrazin und Formyl-aalen [Tris(diformylamino)methan] / Orthoamides and Iminium Salts LXXXV [1]. The Synthesis of Strong Formylating Reagents on a Large Preparative Scale: N;N;N';N'-Tetraformylhydrazine and Formyl-aalen [Tris(diformylamino)methane]
- Phenothiazine-Aromatic Hydrocarbon Acceptor Dyads as Photo-induced Electron Transfer Systems by Ugi Four-Component Reaction
- A Simple Metal-free Synthesis of 2,4,5-Trisubstituted Pyridines and Pyridine N-Oxides by [2+2] Cycloaddition of Enaminones to Propyne Iminium Salts
- Propyne Iminium Salts and Isoquinoline – 1 : 1 and 2 : 1 Adducts
- A Direct Synthesis of a Strongly Zwitterionic 6,6'-Diaminofulvalene
- Neue aromatische Bisguanidin-Kupfer-Komplexe und ihre Anwendung in der ATRP / New Aromatic Bisguanidine Copper Complexes and Their Application in ATRP
- Investigation of Imidazol(in)ium-dithiocarboxylates as Sensors for the Detection of Mercury(II) and Silver(I) Ions
- Syntheses and Characterization of N-(Indolyl)pyridinium Salts and of Their Ylides
- Cu(I)-catalyzed [3+2] Cycloadditions of tert-Butyl (S)-(3-Oxopent-4- yn-2-yl)carbamate to 1-Benzylidenepyrazole-3-one-derived Azomethine Imines
- Zugänge zu Isomeren und Verwandten der Lamellarin-Alkaloide / Approach to Isomers and Structural Relatives of the Lamellarin Alkaloids
- Novel Dihydropyrazines and their Double ortho-Annulation to Hexaazapentacenes
Articles in the same Issue
- Chemistry of Iminium Salts, Imines, and Related Compounds
- Thiaminpyrophosphat – ein natürlich vorkommendes Iminium-Salz. Seine Bedeutung für die mikrobiellen Prozesse bei der Weinbereitung und die Aromabildung im Wein / Thiamine Diphosphate – A Natural Iminium Salt. Its Role in Microbiological Processes During Wine Preparation and on the Aroma of Wine
- Formation of Azolo[1,2,4]triazinium Salts by Reaction of Heterocyclicsubstituted 1-Azo-naphthalen-2-ols with Strong Acids
- Synthesis of Methyl 3-Azidothieno[2,3-b]pyridine-2-carboxylates and Application of the Huisgen Reaction
- Orthoamide und Iminiumsalze, LXXXVII [1]. Eine neue, einfache Synthese für 1,3-Dimethylthymin / Orthoamides and Iminium Salts LXXXVII [1]. A New and Facile Synthesis of 1,3-Dimethylthymine
- Orthoamide und Iminiumsalze, LXXXIV [1]. Die Synthese von starken Formylierungsmitteln im präparativen Großmaßstab: Tris(dichlormethyl)amin / Orthoamides and Iminiumsalts LXXXIV [1]. The Synthesis of Strong Formylating Reagents on a Large Preparative Scale: Tris(chloromethyl)amine
- Orthoamide und Iminiumsalze, LXXXV [1]. Die Synthese von starken Formylierungsmitteln im präparativen Großmaßstab: N,N,N',N'- Tetraformylhydrazin und Formyl-aalen [Tris(diformylamino)methan] / Orthoamides and Iminium Salts LXXXV [1]. The Synthesis of Strong Formylating Reagents on a Large Preparative Scale: N;N;N';N'-Tetraformylhydrazine and Formyl-aalen [Tris(diformylamino)methane]
- Phenothiazine-Aromatic Hydrocarbon Acceptor Dyads as Photo-induced Electron Transfer Systems by Ugi Four-Component Reaction
- A Simple Metal-free Synthesis of 2,4,5-Trisubstituted Pyridines and Pyridine N-Oxides by [2+2] Cycloaddition of Enaminones to Propyne Iminium Salts
- Propyne Iminium Salts and Isoquinoline – 1 : 1 and 2 : 1 Adducts
- A Direct Synthesis of a Strongly Zwitterionic 6,6'-Diaminofulvalene
- Neue aromatische Bisguanidin-Kupfer-Komplexe und ihre Anwendung in der ATRP / New Aromatic Bisguanidine Copper Complexes and Their Application in ATRP
- Investigation of Imidazol(in)ium-dithiocarboxylates as Sensors for the Detection of Mercury(II) and Silver(I) Ions
- Syntheses and Characterization of N-(Indolyl)pyridinium Salts and of Their Ylides
- Cu(I)-catalyzed [3+2] Cycloadditions of tert-Butyl (S)-(3-Oxopent-4- yn-2-yl)carbamate to 1-Benzylidenepyrazole-3-one-derived Azomethine Imines
- Zugänge zu Isomeren und Verwandten der Lamellarin-Alkaloide / Approach to Isomers and Structural Relatives of the Lamellarin Alkaloids
- Novel Dihydropyrazines and their Double ortho-Annulation to Hexaazapentacenes