Direct Synthesis of Molecular Self-Complexes in the Indole Series

Article abstract of DOI:10.1007/BF00742838

A method for the alkylation of 3-unsubstituted indoles by means of 1-(ω-haloalkyl)-pyridinium salts via the Friedel-Crafts reaction with the aid of complex catalysts, viz., complexes of zinc, tin, and titanium chlorides with pyridine, was developed.On the basis of a study of the electronic spectra of the resulting 1-(3-indolyl-alkyl)pyridinium salts it was shown that they are molecular self-complexes.The stabilities of the molecular self-complexes were investigated as a function of the length of the alkyl chain and the character of the substituents in the indole ring.